Eclipse Engineering Guide

Engineering 

Guide

ECLIPSE 

COMBUSTION 

ENGINEERING 

GUIDE 

Published by 

Eclipse, Inc.

Copyright 1986 

by 

Eclipse, Inc. 

1665 Elmwood Road 

Rockford, Illlinois 61103 

All Rights Reserved. 

Eighth Edition 

EFE-825, 8/04 

Printed in the United States of America

CONTENTS 

1. Orifices & Flows 

Coefficients of Discharge for Various Types of Orifices . . . . . . . . . . . . . . . . . . . . 4 

Orifice Flow Formulas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 

Orifice Capacity Tables, Low Pressure Gas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 

Orifice Capacity Tables, High Pressure Gas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 

Piping Pressures Losses, Air . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 

Piping Pressure Losses, Natural Gas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 

High Pressure (Compressible) Flow of Natural Gas in Pipes . . . . . . . . . . . . . . . . . 14 

Equivalent Lengths of Standard Pipe Fittings & Valves . . . . . . . . . . . . . . . . . . . . 14 

Simplified Selection of Air, Gas and Mixture Piping Size . . . . . . . . . . . . . . . . . . . 15 

Quick Method for Sizing Air Piping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 

Sizing Branch Piping by the Equal Area Method . . . . . . . . . . . . . . . . . . . . . . . . . 16 

C v Flow Factor Conversion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 

Duct Velocity & Flow Measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 

2. Fan Laws & Blower Application Engineering 

Theoretical Flow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 

Fan Laws . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 

Blower Horsepower Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 

Blowers Used as Suction Fans . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 

The Effect of Pressure on Air . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 

The Effect of Altitude on Air . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 

The Effect of Temperature on Air . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 

3. Gas 

Physical Properties of Commercial Fuel Gases . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 

Combustion Properties of Commercial Fuel Gases 

Air/Gas Ratio, Flammability Limits, Ignition Temperature & Flame Velocity . . . 22 

Heating Value, Heat Release & Flame Temperature . . . . . . . . . . . . . . . . . . . . . 23 

Combustion Products & CO 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 

Equivalent Propane/Air & Butane/Air Btu Tables . . . . . . . . . . . . . . . . . . . . . . . . . 24 

Propane/Air & Butane/Air Mixture Specifications . . . . . . . . . . . . . . . . . . . . . . . . 24 

4. Oil 

Fuel Oil Specifications Per ANSI/ASTM D 396-79 . . . . . . . . . . . . . . . . . . . . . . . 25 

Typical Properities of Commercial Fuel Oils in the U.S. . . . . . . . . . . . . . . . . . . . . 26 

Fuel Oil Viscosity Conversions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 

°API Vs. Oil Specific Gravity & Gross Heating Value . . . . . . . . . . . . . . . . . . . . . 27 

Oil Piping Pressure Losses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 

Oil Temperature Drop in °F Per 100 Foot of Pipe . . . . . . . . . . . . . . . . . . . . . . . . . 29 

5. Steam & Water 

Boiler Terminology & Conversion Factors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 

Properties of Saturated Steam . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 

Btu/Hr. Required to Generate One Boiler H.P. . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 

Sizing Water Piping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 

Sizing Steam Piping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 

2

6. Electrical Data 

Electrical Formulas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 

Electrical Wire – Dimensions & Ratings . . . . . . . . . . . . . . . . . . . . . . . . . 33 

NEMA Size Starters for Motors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 

NEMA Enclosures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 

Electric Motors – Full Load Current, Amperes . . . . . . . . . . . . . . . . . . . . . . 34 

7. Process Heating 

Heat Balances – Determining the Heat Needs of Furnaces and Ovens . . . . 35 

Thermal Properties of Various Materials . . . . . . . . . . . . . . . . . . . . . . . . . . .37 

Thermal Capacities of Metals & Alloys . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 

Industrial Heating Operations – Temperature & Heat Requirements . . . . . . 41 

Crucibles for Metal Melting – Dimensions & Capacities . . . . . . . . . . . . . . 43 

Radiant Tubes – Sizing & Input Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 

Heat Losses, Heat Storage & Cold Face Temperatures – Refractory Walls . 44 

Air Heating & Fume Incineration Heat Requirements 

Using “Raw Gas” Burners . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 

Using Burners with Separate Combustion Air Sources . . . . . . . . . . . . . . . 45 

Fume Incineration – Selection & Sizing Guidelines . . . . . . . . . . . . . . . . . . 46 

Liquid Heating – Burner Sizing Guidelines . . . . . . . . . . . . . . . . . . . . . . . . . 47 

Black Body Radiation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 

Thermocouple Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 

Orton Standard Pyrometric Cone Temperature Equivalents . . . . . . . . . . . . . 50 

8. Combustion Data 

Available Heat for Birmingham Natural Gas . . . . . . . . . . . . . . . . . . . . . . . . 51 

Available Heat for Various Fuel Gases . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 

Flue Gas Analysis Chart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 

Theoretical Flame Tip Temperature vs. Excess Air . . . . . . . . . . . . . . . . . . . 52 

Heat Transfer Relationships . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 

Thermal Head & Cold Air Infiltration into Furnaces . . . . . . . . . . . . . . . . . . 53 

Furnace Flue Sizing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 

9. Mechanical Data 

Dimensional and Capacity Data – Schedule 40 Pipe . . . . . . . . . . . . . . . . . . 54 

Dimensions of Malleable Iron Threaded Fittings . . . . . . . . . . . . . . . . . . . . . 55 

Sheet Metal Gauges & Weights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56 

Steel Wire Gauges & Weights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56 

Circumferences & Areas of Circles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57 

Drill Size Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59 

Tap Drill Sizes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60 

Drilling Templates – Pipe Flanges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60 

10. Abbreviations & Symbols 

Abbreviations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61 

Electrical Symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62 

11. Conversion Factors 

General Conversion Factors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64 

Temperature Conversions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68 

Pressure Conversions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69 

Index . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .72 

Tech Notes 

Table of Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .73 

3

Sharp Edge 

C d = 0.60 

The flow of air or gas through an orifice can be determined 

by the formula 

h 

Q = 1658.5 x Ax C g d 

where Q =flow, cfh 

A =area of the orifice, sq. in. (see Pages 57 & 58) 

Cd =discharge coefficient of the orifice 

(see above) 

h =pressure drop across the orifice,″ w.c. 

g =specific gravity of the gas, based on standard 

air at 1.0 (see Pages 19, 20, & 22 thru 24.) 

1. Sizing Orifice Plates 

To calculate the size of an orifice plate, this equation can 

be rearranged as follows: 

A= Q x 

g 

1658.5 x C h 

d 

2. Effect of Changes in Operating Conditions on 

Flow through an Orifice – General Relationship 

Q2 A2 Cd2 h2 g1 = x x x 

Q1 A1 Cd1 h g 1 2 

If any of the factors in this relationship remain constant 

from Condition 1 to Condition 2, they can be dropped out of 

the equation, yielding these simplified relationships. Each of 

them assumes only one factor has been changed. 

2a.Flow Change vs. Orifice Area Change 

Q2 A2 = 

Q1 A1 2b.Flow Change vs. Pressure Drop Change 

Q2 h2 = 

Q 1 

Reentrant 

0.72 

h 1 

This is the so-called “square root law.” 

2c.Flow Change vs. Specific Gravity Change 

Q2 g1 = 

Q g 1 2 

CHAPTER 1 – ORIFICES & FLOWS 

COEFFICIENTS OF DISCHARGE FOR VARIOUS TYPES OF ORIFICES 

Round Edge 

0.97 

Short Pipe 

0.82 

Converging 

depends on angle. See 

curve at right. 

Coefficient of Discharge (Cd ) 

0.95 

4 

0.93 

0.91 

0.89 

0.87 

0.85 

ORIFICE FLOW FORMULAS 

3.Effect of Changes in Operating Conditions on Pressure 

Drop Across an Orifice–General Relationship: 

2 h2 Q2 = x A1 2 

x Cd1 2 

x g2 ( h1 Q ) ( ) ( ) 

1 A2 Cd2 g1 Again, if any of the factors in this equation are unchanged 

from Condition 1 to Condtion 2, they can be dropped out to 

form simplified relationships: 

3a.Pressure Drop Change vs. Flow Change 

2 h2 Q2 = 

h 1 

Q 1 

This is the square root law, stated another way. 

3b.Pressure Drop Change vs. Orifice Area Change 

2 h2 A1 = 

h 1 

A 2 

3c.Pressure Drop Change vs. Specific Gravity Change 

h2 g2 = 

h 1 

Orifices and Nozzles Discharging from Plenum 

0.83 

0 2 4 6 8 10 12 14 16 18 20 22 24 

Angle of Convergence in Degrees 

( 

( 

g 1 

) 

) 

This relationship may not apply where specific gravity has 

been changed by a change in gas temperature. See Page 25. 

4. Effect of Changes in Gas Temperature on Flow and 

Pressure Drop through an Orifice 

Raising a gas’s temperature has two effects – it increases 

the volume and decreases the specific gravity, both in proportion 

to the ratio of the absolute temperatures. If we are concerned 

with changes in mass flows (scfh), these relationships 

must be used: 

4a.Flow Change vs. Temperature Change 

Q2 Q1 = 

TADS1 TABB2 4b.Pressure Drop Change vs. Temperature Change 

h2 TABS2 h 

= 

1 TABS1 to maintain constant scfh 

NOTE: The loss is least at 13˚

Flows in these tables are based on an orifice pressure drop 

of 1″ w.c. and a coefficient of discharge (C d ) of 1.0. 

To determine flow through an orifice of a known diameter: 

1. Locate the orifice diameter in the left-hand column of the 

table. 

2. Read across to the column corresponding to the gas being 

measured. This is the uncorrected flow. 

3. Multiply this flow by the coefficient of discharge of the 

orifice. (see page 4) 

4. Correct this flow to the pressure drop actually measured, 

using the square root law (equation 2b, page 4). 

Example: What is the flow of natural gas through a 7/32" 

diameter sharp edge orifice at 6″ w.c. pressure drop? 

From the table, uncorrected natural gas flow through a 

7/32" orifice is 80.7 cfh at 1″ w.c. 

C d for a sharp edge orifice is 0.60 (page 1.1), so corrected 

flow is 80.7 x 0.60 = 48.4 cfh at 1" w.c. pressure drop. 

Per equation 2b, page 4, 

Q 2 = h 2 or Q2 = Q 1 x h 2 

Q 1 h 1 h 1 

Substituting the numbers for this case: 

Q 2 = 48.4 x 

6″ w.c. = 119 cfh 

1″ w.c. 

ORIFICE CAPACITY TABLES 

LOW PRESSURE GAS 

CAPACITY, CFH @ 1″ W.C. PRESSURE DROP 

AND COEFFICIENT OF DISCHARGE OF 1.0 

5 

To determine the orifice size to handle a known flow at a 

specified pressure drop, reverse the process: 

1. Correct the known flow to a pressure drop of 1″ w.c., 

using the square root law. 

2. Divide the flow by the orifice coefficient. 

3. In the orifice table, locate the column for the gas under 

consideration. In this column, locate the flow closest to 

the corrected value found in step 2. 

4. Read to the left to find the corrected orifice size. 

Example: Size a gas jet for a mixer. Entrance to the jet orifice 

converges at a 15° included angle. Gas is propane. Required 

flow is 120 cfh at 30″ w.c. pressure drop. 

Per equation 2b, page 4, 

Q 2 = h 2 , or Q2 = Q1 x h 2 

Q 1 h 1 h 1 


Q2 = 120 x 1 = 22 cfh 

30 

From page 1.1, Cd for a 15° convergent nozzle is 0.94, so 

corrected flow is 

22 ÷ 0.94 = 23.4 cfh. 

Locate 23.4 cfh in the propane column of the orifice 

table and then read to the left to find a #26 drill size orifice. 

Natural Propane/ 

Drill Dia. Gas Air Air Propane Butane 

Size In. Area 0.60 Sp. Gr. 1.0 Sp. Gr. 1.29 Sp. Gr. 1.5 Sp. Gr. 2.0 Sp. Gr. 

80 .0135 .000143 .308 .239 .210 .195 .169 

79 .0145 .000165 .355 .275 .242 .225 .195 

1/64 .0156 .00019 .409 .317 .279 .259 .224 

78 .016 .00020 .431 .334 .294 .272 .236 

77 .018 .00025 .538 .417 .367 .340 .295 

76 .020 .00031 .668 .517 .455 .422 .366 

75 .021 .00035 .754 .584 .514 .477 .413 

74 .0225 .00040 .861 .668 .587 .545 .472 

73 .024 .00045 .969 .751 .661 .613 .531 

72 .025 .00049 1.06 .817 .720 .667 .578 

71 .026 .00053 1.14 .884 .778 .722 .625 

70 .028 .00062 1.33 1.03 .910 .844 .731 

69 .0292 .00067 1.44 1.12 .984 .912 .790 

68 .030 .00075 1.61 1.25 1.10 1.02 .885 

1/32 .0312 .00076 1.64 1.27 1.12 1.04 .896 

67 .032 .00080 1.72 1.33 1.17 1.09 .944 

66 .033 .00086 1.85 1.43 1.26 1.17 1.01 

65 .035 .00092 2.07 1.60 1.41 1.31 1.13 

64 .036 .00102 2.20 1.70 1.50 1.39 1.20 

63 .037 .00108 2.33 1.80 1.59 1.47 1.27 

62 .038 .00113 2.43 1.88 1.66 1.54 1.33 

61 .039 .00119 2.56 1.98 1.75 1.62 1.40 

60 .040 .00126 2.71 2.10 1.85 1.72 1.49 

59 .041 .00132 2.84 2.20 1.94 1.8 1.56 

58 .042 .00138 2.97 2.30 2.03 1.88 1.63






57 .043 .00145 3.12 2.42 2.13 1.97 1.71 

56 .0465 .00170 3.66 2.84 2.5 2.32 2.01 

3/64 .0469 .00173 3.73 2.89 2.54 2.36 2.04 

55 .0520 .00210 4.52 3.50 3.08 2.86 2.48 

54 .0550 .0023 4.95 3.84 3.38 3.13 2.71 

53 .0595 .0028 6.03 4.67 4.11 3.81 3.30 

1/16 .0625 .0031 6.68 5.17 4.55 4.22 3.66 

52 .0635 .0032 6.89 5.34 4.7 4.36 3.77 

51 .0670 .0035 7.54 5.84 5.14 4.77 4.13 

50 .070 .0038 8.18 6.34 5.58 5.18 4.48 

49 .073 .0042 9.04 7.01 6.17 5.72 4.95 

48 .076 .0043 9.26 7.17 6.31 5.86 5.07 

5/64 .0781 .0048 10.3 8.01 7.05 6.54 5.66 

47 .0785 .0049 10.5 8.17 7.2 6.67 5.78 

46 .081 .0051 11. 8.51 7.49 6.95 6.02 

45 .082 .0053 11.4 8.84 7.78 7.22 6.25 

44 .086 .0058 12.5 9.67 8.52 7.9 6.84 

43 .089 .0062 13.4 10.3 9.11 8.44 7.31 

42 .0935 .00687 14.8 11.4 10. 9.36 8.1 

3/32 .0937 .0069 14.9 11.5 10.1 9.40 8.14 

41 .096 .0072 15.5 12. 10.6 9.81 8.49 

40 .098 .0075 16.2 12.5 11. 10.2 8.85 

39 .0995 .0078 16.8 13. 11.5 10.6 9.2 

38 .1015 .0081 17.4 13.5 11.9 11.0 9.55 

37 .104 .0085 18.3 14.2 12.5 11.6 10. 

36 .1065 .0090 19.4 15. 13.2 12.3 10.6 

7/64 .1093 .0094 20.2 15.7 13.8 12.8 11.1 

35 .110 .0095 20.5 15.8 14. 12.9 11.2 

34 .111 .0097 20.9 16.2 14.2 13.2 11.4 

33 .113 .0100 21.5 16.7 14.7 13.6 11.8 

32 .116 .0106 22.8 17.7 15.6 14.4 12.5 

31 .120 .0113 24.3 18.8 16.6 15.4 13.3 

1/8 .125 .0123 26.4 20.4 18. 16.7 14.5 

30 .1285 .0130 27.9 21.6 19. 17.6 15.3 

29 .136 .0145 31.1 24.1 21.2 19.7 17. 

28 .1405 .0155 33.3 25.8 22.7 21. 18.2 

9/64 .1406 .0156 33.5 25.9 22.8 21.2 18.3 

27 .144 .0163 35. 27.1 23.9 22.1 19.2 

26 .147 .0174 37.3 28.9 25.5 23.6 20.4 

25 .1495 .0175 37.5 29.1 25.6 23.7 20.6 

24 .152 .0181 38.8 30.1 26.5 24.6 21.3 

23 .154 .0186 39.9 30.9 27.2 25.2 21.9 

5/32 .1562 .0192 41.2 31.9 28.1 26.1 22.6 

22 .157 .0193 41.4 32.1 28.2 26.2 22.7 

21 .159 .0198 42.5 32.9 29. 26.9 23.3 

20 .161 .0203 43.6 33.7 29.7 27.5 23.9 

19 .166 .0216 46.3 35.9 31.6 29.3 25.4 

18 .1695 .0226 48.5 37.6 33.1 30.7 26.6 

11/64 .1719 .0232 49.8 38.6 33.9 31.5 27.3 

17 .175 .0235 50.4 39.1 34.4 31.9 27.6 

16 .177 .0246 52.8 40.9 36. 33.4 28.9 

15 .180 .0254 54.5 42.2 37.2 34.5 29.9 

14 .182 .0260 55.8 43.2 38. 35.3 30.6 

13 .185 .0269 57.7 44.7 39.4 36.5 31.6 

3/16 .1875 .0276 59.2 45.9 40.4 37.5 32.4 

6






12 .189 .02805 60.2 46.6 41. 38.1 33. 

11 .191 .02865 61.5 47.6 41.9 38.9 33.7 

10 .1935 .0294 63.1 48.9 43. 39.9 34.6 

9 .196 .0302 64.8 50.2 44.2 41. 35.5 

8 .199 .0311 66.7 51.7 45.5 42.2 36.5 

7 .201 .0316 67.8 52.5 46.2 42.9 37.1 

13/64 .2031 .0324 69.5 53.8 47.4 44. 38.1 

6 .204 .0327 70.2 54.3 47.8 44.4 38.4 

5 .2055 .0332 71.2 55.2 48.6 45.1 39. 

4 .209 .0343 73.6 57.0 50.2 46.5 40.3 

3 .213 .0356 76.4 59.2 52.1 48.3 41.8 

7/32 .2187 .0376 80.7 62.5 55. 51. 44.2 

2 .221 .0384 82.4 63.8 56.2 52.1 45.1 

1 .228 .0409 87.8 68. 59.8 55.5 48.1 

A .234 .0430 92.3 71.5 62.9 58.4 50.5 

15/64 .2343 .0431 92.5 71.6 63.1 58.5 50.7 

B .238 .0444 95.3 73.8 65. 60.3 52.2 

C .242 .0460 98.7 76.5 67.3 62.4 54.1 

D .246 .0475 102. 78.9 69.5 64.5 55.8 

1/4 .250 .0491 105. 81.6 71.8 66.6 57.7 

F .257 .0519 111. 86.3 75.9 70.4 61. 

G .261 .0535 115. 88.9 78.3 72.6 62.9 

17/64 .2656 .0554 119. 92.1 81.1 75.2 65.1 

H .266 .0556 119.3 92.4 81.4 75.4 65.3 

I .272 .0580 124. 96.4 84.9 78.7 68.2 

J .277 .0601 129. 99.9 87.9 81.6 70.6 

K .281 .0620 133. 103. 90.7 84.1 72.9 

9/32 .2812 .0621 133.2 103.2 90.9 84.3 73. 

L .290 .0660 142. 110. 96.6 89.6 77.6 

M .295 .0683 147. 113. 99.9 92.7 80.3 

19/64 .2968 .0692 148. 115. 101. 93.9 81.3 

N .302 .0716 154. 119. 105. 97.2 84.1 

5/16 .3125 .0767 165. 127. 112. 104. 90.1 

O .316 .0784 168. 130. 115. 106. 92.1 

P .323 .0820 176. 136. 120. 111. 96.4 

21/64 .3281 .0846 182. 141. 124. 115. 99.4 

Q .332 .0866 186. 144. 127. 118. 102. 

R .339 .0901 193. 150. 132. 122. 106. 

11/32 .3437 .0928 199. 154. 136. 126. 109. 

S .348 .0950 204. 158. 139. 129. 112. 

T .358 .1005 216. 167. 147. 136. 118. 

23/64 .3593 .1014 218. 169. 148. 138. 119. 

U .368 .1063 228. 177. 156. 144. 125. 

3/8 .375 .1104 237. 184. 162. 150. 130. 

V .377 .1116 239. 185. 163. 151. 131. 

W .386 .1170 251. 194. 171. 159. 137. 

25/64 .3906 .1198 257. 199. 175. 163. 141. 

X .397 .1236 265. 205. 181. 168. 145. 

Y .404 .1278 274. 212. 187. 173. 150. 

13/32 .4062 .1296 278. 215. 190. 176. 152. 

Z .413 .1340 288. 223. 196. 182. 157. 

27/64 .4219 .1398 300. 232. 205. 190. 164. 

7/16 .4375 .1503 322. 250. 220. 204. 177. 

29/64 .4531 .1613 346. 268. 236. 219. 190. 

15/32 .4687 .1726 370. 287. 253. 234. 203. 

7






31/64 .4843 .1843 395. 306. 270. 250. 217. 

1/2 .50 .1963 421. 326. 287. 266. 231. 

33/64 .5156 .2088 448. 347. 306. 283. 245. 

17/32 .5312 .2217 476. 368. 324. 301. 261. 

35/64 .5468 .2349 504. 390. 344. 319. 276. 

9/16 .5625 .2485 533. 413. 364. 337. 292. 

37/64 .5781 .2625 563. 436. 384. 356. 308. 

19/32 .5937 .2769 594. 460. 405. 376. 325. 

39/64 .6093 .2916 626. 485. 427. 396. 343. 

5/8 .625 .3068 658. 510. 449. 416. 361. 

41/64 .6406 .3223 691. 536. 472. 437. 379. 

21/32 .6562 .3382 725. 562. 495. 459. 397. 

43/64 .6718 .3545 760. 589. 519. 481. 417. 

11/16 .6875 .3712 796. 617. 543. 504. 436. 

45/64 .7031 .3883 833. 645. 568. 527. 456. 

23/32 .7187 .4057 870. 674. 594. 551. 477. 

47/64 .7343 .4236 909. 704. 620. 575. 498. 

3/4 .750 .44179 948. 734. 646. 599. 519. 

49/64 .7656 .46040 988. 765. 674. 625. 541. 

25/32 .7813 .47937 1029. 796. 701. 651. 563. 

51/64 .7969 .49873 1070. 829. 730. 677. 586. 

13/16 .8125 .51849 1112. 862. 759. 704. 609. 

53/64 .8281 .53862 1156. 895. 788. 731. 633. 

27/32 .8438 .55914 1200. 929. 818. 759. 657. 

55/64 .8594 .5800 1244. 964. 849. 787. 682. 

7/8 .8750 .60132 1290. 999. 880. 816. 707. 

29/32 .9062 .64504 1384. 1072. 944. 875. 758. 

15/16 .9375 .69029 1481. 1147. 1010. 937. 811. 

31/32 .9688 .73708 1581. 1225. 1079. 1000. 866. 

1 1.0 .7854 1685. 1305. 1149. 1066. 923. 

1-1/16 1.063 .88664 1902. 1474. 1297. 1203. 1042. 

1-1/8 1.125 .99402 2133. 1652. 1455. 1349. 1168. 

1-3/16 1.188 1.1075 2376. 1841. 1621. 1503. 1302. 

1-1/4 1.250 1.2272 2633. 2040. 1796. 1665. 1442. 

1-5/16 1.313 1.3530 2903. 2249. 1980. 1836. 1590. 

1-3/8 1.375 1.4849 3186. 2468. 2173. 2015. 1745. 

1-1/2 1.5 1.7671 3791. 2937. 2586. 2398. 2077. 

1-9/16 1.563 1.9174 4114. 3187. 2806. 2602. 2253. 

1-5/8 1.625 2.0739 4450. 3447. 3035. 2814. 2437. 

1-11/16 1.688 2.2365 4799. 3717. 3273. 3035. 2628. 

1-3/4 1.75 2.4053 5161. 3998. 3520. 3264. 2827. 

1-13/16 1.813 2.5802 5536. 4288. 3776. 3501. 3032. 

1-7/8 1.875 2.7612 5924. 4589. 4040. 3747. 3245. 

1-15/16 1.938 2.9498 6329. 4903. 4316. 4003. 3467. 

2 2.0 3.1416 6741. 5221. 4597. 4263. 3692. 

2-1/8 2.125 3.5466 7610. 5894. 5190. 4813. 4168. 

2-1/4 2.250 3.9761 8531. 6608. 5818. 5396. 4673. 

2-3/8 2.375 4.4301 9505. 7363. 6483. 6012. 5206. 

2-1/2 2.50 4.9087 10532. 8158. 7183. 6661. 5769. 

2-5/8 2.625 5.4119 11612. 8995. 7919. 7344. 6360. 

2-3/4 2.75 5.9396 12744. 9872. 8691. 8060. 6980. 

2-7/8 2.875 6.4918 13929. 10789. 9499. 8809. 7629. 

8

These tables list compressible flows of high pressure gases 

through orifices and spuds. They are based on an orifice pressure 

drop of 10 psi and a coefficient of discharge (C d) of 1.0. 

They also assume the gas is discharging to a region of atmospheric 

pressure. 

To determine flow through an orifice of a known diameter: 

1. Locate the orifice diameter in the left-hand column of the 

table. 

2. Read across to the column corresponding to the gas being 

measured. This is the uncorrected flow. 

3. Multiply this flow by the coefficient of discharge of the 

orifice. (see page 4) 

4. Correct this flow to the pressure actually measured ahead 

of the orifice (P) using the following relationship: 

Q p = Q 10 

ORIFICE CAPACITY TABLES FOR HIGH PRESSURE GASES 

P + 14.7 

24.7 

Where Q p is the unknown flow 

Q 10 is the flow at 10 psig from the table 

Example: What is the flow of propane – air mixture through a 

3/64" diameter jet with a 15° angle of convergence at 35 psig? 

From the table, uncorrected propane – air flow through a 

3/64" orifice is 41 scfh at 10 psig. 

C d for 15° convergent jet is 0.94 (page 4), so corrected flow 

is 41 x 0.94 = 38.5 scfh at 10 psig. 

Corrected flow for 35 psig pressure, per the equation above, is 

Q p = 38.5 35 + 14.7 = 77.5 scfh 

24.7 

9 

To determine the orifice size to handle a known flow at a 

specified pressure drop, reverse the process: 

1. Correct the known flow to a pressure drop of 10 psig, using 

the equation above. 

2. Divide the flow by the orifice coefficient. 

3. In the orifice table, locate the column for the gas under 

consideration. In this column, locate the flow closest to the 

corrected value found in step 2. 

4. Read to the left to find the corrected orifice size. 

Example: Size an airjet with a convergent inlet of 15°. 

Required flow is 450 scfh at 20 psig inlet pressure. 

Per the equation above, 

Qp = Q P + 14.7, 

10 or Q10 = Q 24.7 

p 

24.7 P + 14.7 


Q 10 = 450 24.7 = 320 scfh 

20 + 14.7 

From page 4, C d for a 15° convergent nozzle is 0.94, so corrected 

flow is 

320 ÷ 0.94 = 340 scfh. 

Locate 340 scfh in the air column of the orifice table. Closest 

value is 341 scfh, which requires a 1/8" diameter jet. 

CAPACITY, SCFH @ 10 PSI PRESSURE DROP, DISCHARGING TO ATMOSPHERE, 

WITH COEFFICIENT OF DISCHARGE OF 1.0 

Drill Area Natural Gas Air Propane/Air Propane Butane 

Size Sq. In. 0.60 Sp. Gr. 1.0 Sp. Gr. 1.29 Sp. Gr. 1.5 Sp. Gr. 2.0 Sp. Gr. 

80 .000143 4.9 3.8 3.3 3.1 2.7 

79 .000165 5.6 4.3 3.8 3.5 3.0 

1/64 — .00019 6.6 5.1 4.5 4.2 3.6 

78 .00020 7.0 5.4 4.8 4.4 3.8 

77 .00025 9.2 7.1 6.3 5.8 5.0 

76 .00031 10.8 8.4 7.4 6.9 5.9 

75 .00035 11.9 9.2 8.1 7.5 6.53 

74 .00040 13.6 10.5 9.2 8.6 7.4 

73 .00045 15.6 12.1 10.7 9.9 8.6 

72 .00049 17.0 13.2 11.6 10.8 9.3 

71 .00053 18.5 14.3 12.6 11.7 10.1 

70 .00062 21 16.4 14.4 13.4 11.6 

69 .00067 23 18.1 15.9 14.8 12.8 

68 .00075 26 20 17.6 16.3 14.1 

1/32 — .00076 27 21 18.5 17.1 14.8 

67 .00080 28 22 19.4 18.0 15.6 

66 .00086 30 23 20 18.8 16.3 

65 .00096 34 26 23 21 18.4 

64 .00102 35 27 24 22 19.1 

63 .00108 37 29 26 24 20 

62 .00113 40 31 27 25 22 

61 .00119 41 32 28 26 23 

60 .00126 44 34 30 28 24

CAPACITY, SCFH @ 10 PSI PRESSURE DROP, DISCHARGING TO 

ATMOSPHERE, WITH COEFFICIENT OF DISCHARGE OF 1.0 (Cont’d) 



59 .00132 45 35 31 29 25 

58 .00138 48 37 33 30 26 

57 .00145 52 40 35 33 28 

56 .00170 59 46 41 38 33 

3/64 — .00173 61 47 41 38 33 

55 .00210 75 58 51 47 41 

54 .00230 84 65 57 53 46 

53 .00280 98 76 67 62 54 

1/16 — .00310 108 84 74 69 59 

52 .00320 112 87 77 71 62 

51 .00350 124 96 85 78 68 

50 .00380 136 105 92 86 74 

49 .00420 147 114 100 93 81 

48 .00430 160 124 109 101 88 

5/64 — .00480 169 131 115 107 93 

47 .00490 172 133 117 109 94 

46 .00510 182 141 124 115 100 

45 .00530 187 145 128 118 103 

44 .00580 205 159 140 130 112 

43 .00620 219 170 150 139 120 

3/32 (42) .00690 243 188 166 154 133 

41 .00720 244 189 166 154 134 

40 .00750 266 206 181 168 146 

39 .00780 275 213 188 174 151 

38 .00810 285 221 195 180 156 

37 .00850 300 232 204 189 164 

36 .00900 315 244 215 199 173 

7/64 — .00940 332 257 226 210 182 

35 .00950 336 260 229 212 184 

34 .00970 342 265 233 216 187 

33 .01000 354 274 241 224 194 

32 .01060 374 290 255 237 205 

31 .01130 400 310 273 253 219 

1/8 — .01230 440 341 300 278 241 

30 .01300 458 355 313 290 251 

29 .01450 514 398 350 325 281 

28 .01550 550 426 375 348 301 

9/64 — .01560 553 428 377 349 303 

27 .01630 572 443 390 362 313 

26 .01740 599 464 409 379 328 

25 .01750 621 481 423 393 340 

24 .01810 642 497 437 406 351 

23 .01860 660 511 450 417 361 

5/32 — .01920 678 525 462 429 371 

22 .01930 684 530 467 433 375 

21 .01980 702 544 479 444 385 

20 .02030 728 564 497 461 399 

19 .02160 766 593 522 484 419 

18 .02260 800 620 546 506 438 

11/64 — .02320 822 637 561 520 450 

17 .02350 830 643 566 525 455 

16 .02460 871 675 594 551 477 

15 .02540 904 700 616 572 495 

14 .02600 920 713 628 582 503 

13 .02690 951 737 649 602 521 

3/16 — .02760 976 756 666 617 534 

12 .02805 993 769 677 628 544 

10

CAPACITY, SCFH @ 10 PSI PRESSURE DROP, DISCHARGING TO 

ATMOSPHERE, WITH COEFFICIENT OF DISCHARGE OF 1.0 (Cont’d) 



11 .02865 1015 786 692 642 556 

10 .02940 1041 806 710 658 570 

9 .03020 1066 826 727 674 584 

8 .03110 1100 852 750 696 602 

7 .03160 1122 869 765 710 614 

13/64 — .03240 1148 889 783 726 629 

6 .03270 1155 895 788 731 633 

5 .03320 1172 908 799 741 642 

4 .03430 1216 942 829 769 666 

3 .03560 1263 978 861 799 692 

7/32 — .03760 1327 1028 905 839 727 

2 .03840 1361 1054 928 861 745 

1 .04090 1447 1121 987 915 793 

A .04300 1523 1180 1039 963 834 

15/64 — .04310 1529 1184 1042 967 837 

B .04440 1571 1217 1072 994 861 

C .04600 1627 1260 1109 1029 891 

D .04750 1686 1306 1150 1066 923 

1/4 E .04910 1738 1346 1185 1099 952 

F .05190 1836 1422 1252 1161 1006 

G .05350 1891 1465 1290 1196 1036 

17/64 — .05540 1960 1518 1336 1239 1073 

H .05560 1969 1525 1343 1245 1078 

I .05800 2054 1591 1401 1299 1125 

J .06010 2128 1648 1451 1346 1165 

K .06200 2192 1698 1495 1386 1201 

9/32 — .06210 2200 1704 1500 1391 1205 

L .06600 2337 1810 1594 1478 1280 

M .06830 2418 1873 1649 1529 1324 

19/64 — .06920 2448 1896 1669 1548 1341 

N .07160 2534 1963 1728 1603 1388 

5/16 — .07670 2714 2102 1851 1716 1486 

O .07840 2782 2155 1897 1760 1524 

P .08200 2893 2241 1973 1830 1585 

21/64 — .08460 2996 2321 2044 1895 1641 

Q .08660 3065 2374 2090 1938 1679 

R .09010 3193 2473 2177 2019 1749 

11/32 — .09280 3283 2543 2239 2076 1798 

S .09500 3373 2613 2301 2134 1848 

T .10050 3553 2752 2423 2247 1946 

23/64 — .10140 3595 2785 2452 2274 1969 

U .10630 3775 2924 2574 2387 2068 

3/8 — .11040 3912 3030 2668 2474 2143 

V .11160 3959 3067 2700 2504 2169 

W .11700 4135 3203 2820 2615 2265 

25/64 — .11980 4237 3282 2890 2680 2321 

X .12360 4374 3388 2983 2766 2396 

Y .12780 4537 3514 3094 2869 2485 

13/32 — .12960 4580 3548 3124 2897 2509 

Z .13400 4751 3680 3240 3005 2602 

27/64 — .13980 4943 3829 3371 3126 2708 

7/16 — .15030 5307 4111 3620 3357 2907 

29/64 — .16130 5714 4426 3897 3614 3130 

15/32 — .17260 6121 4741 4452 3871 3352 

31/64 — .18430 6527 5056 4448 4128 3575 

1/2 — .19630 6977 5204 4758 4412 3821 

11

PIPING PRESSURE LOSSES FOR LOW PRESSURE AIR 

Inches w.c. per 100 ft. of Schedule 40 pipe 

Scfh 

Air 1/2" 3/4" 1" 1-1/4" 1-1/2 2" 2-1/2" 3 

40 0.3 — — — — — — — 

50 0.5 — — — — — — — 

100 2.1 0.5 — — — — — — 

200 8.4 1.9 0.5 — — — — — 

300 18.9 4.2 1.2 0.3 — — — — 

400 — 7.5 2.1 0.5 — — — — 

500 — 11.8 3.3 0.8 0.4 — — — 

600 — 16.9 4.7 1.1 0.5 — — — 

700 — — 6.4 1.5 0.7 — — — 

800 — — 8.3 2.0 0.9 — — — 

900 — — 10.5 2.5 1.1 0.3 — — 

1,000 — — 13.0 3.1 1.4 0.4 — — 

1,500 — — — 7.0 3.2 0.8 0.3 — 

2,000 — — — 12.4 5.6 1.4 0.6 — 

3,000 — — — — 12.6 3.2 1.3 0.4 

4,000 — — — — — 5.8 2.2 0.8 

5,000 — — — — — 9.0 3.5 1.2 

6,000 — — — — — 13.0 5.0 1.7 

7,000 — — — — — 17.6 6.9 2.3 

8,000 — — — — — — 9.0 3.0 

9,000 — — — — — — 11.3 3.8 

10,000 — — — — — — 14.0 4.7 

12,000 — — — — — — 20.2 6.8 

14,000 — — — — — — — 9.2 

16,000 — — — — — — — 12.0 

18,000 — — — — — — — 15.2 

20,000 — — — — — — — 18.8 

Scfh 

Air 4" 6" 8" 10" 12 14" 16" 18 

4,000 — — — — — — — — 

6,000 0.4 — — — — — — — 

8,000 0.7 — — — — — — — 

10,000 1.1 — — — — — — — 

12,000 1.6 — — — — — — — 

14,000 2.2 0.3 — — — — — — 

16,000 2.8 0.3 — — — — — — 

18,000 3.6 0.4 — — — — — — 

20,000 4.4 0.5 — — — — — — 

25,000 6.9 0.8 — — — — — — 

30,000 9.9 1.2 0.3 — — — — — 

35,000 13.5 1.6 0.4 — — — — — 

40,000 17.6 2.1 0.5 — — — — — 

50,000 — 3.3 0.7 — — — — — 

60,000 — 4.7 1.0 0.3 — — — — 

70,000 — 6.4 1.4 0.5 — — — — 

80,000 — 8.3 1.9 0.6 — — — — 

90,000 — 10.5 2.4 0.8 0.3 — — — 

100,000 — 13.0 2.9 0.9 0.4 — — — 

120,000 — 18.7 4.2 1.3 0.5 0.3 — — 

140,000 — — 5.7 1.8 0.7 0.4 — — 

160,000 — — 7.4 2.4 0.9 0.5 0.3 — 

180,000 — — 9.4 3.0 1.2 0.7 0.3 — 

200,000 — — 11.6 3.7 1.4 0.8 0.4 — 

250,000 — — 18.2 5.8 2.2 1.3 0.6 0.3 

300,000 — — — 8.4 3.2 1.9 0.9 0.5 

350,000 — — — 11.4 4.4 2.5 1.3 0.6 

400,000 — — — 14.9 5.7 3.3 1.6 0.8 

450,000 — — — 18.8 7.2 4.2 2.1 1.1 

500,000 — — — — 9.0 5.2 2.6 1.3 

550,000 — — — — 10.8 6.2 3.1 1.6 

600,000 — — — — 12.9 7.4 3.7 1.9 

650,000 — — — — 15.1 8.7 4.4 2.2 

700,000 — — — — 17.5 10.1 5.0 2.5 

800,000 — — — — — 13.2 6.6 3.3 

900,000 — — — — — 16.7 8.3 4.2 

1,000,000 — — — — — 20.6 10.3 5.2 

1,100,000 — — — — — — 12.5 6.3 

1,200,000 — — — — — — 14.8 7.5 

1,300,000 — — — — — — 17.4 8.8 

1,400,000 — — — — — — 20.2 10.2 

1,600,000 — — — — — — — 13.3 

1,800,000 — — — — — — — 16.8 

2,000,000 — — — — — — — 20.8 

12

PIPING PRESSURE LOSSES FOR LOW PRESSURE NATURAL GAS 


Scfh 

Nat. Gas 3/8" 1/2" 3/4" 1" 1-1/4" 1-1/2" 2" 

25 0.3 — — — — — — 

50 1.1 0.3 — — — — — 

75 2.5 0.7 — — — — — 

100 4.4 1.2 0.3 — — — — 

125 6.9 1.9 0.4 — — — — 

150 9.9 2.8 0.6 — — — — 

175 13.5 3.8 0.9 — — — — 

200 17.6 5.0 1.1 0.3 — — — 

300 — 11.2 2.5 0.7 — — — 

400 — 19.8 4.5 1.2 0.3 — — 

500 — — 7.0 1.9 0.5 — — 

600 — — 10.1 2.8 0.7 0.3 — 

700 — — 13.8 3.8 0.9 0.4 — 

800 — — 18.0 4.9 1.2 0.5 — 

900 — — — 6.3 1.5 0.7 — 

1,000 — — — 7.7 1.9 0.8 — 

1,500 — — — 17.4 4.2 1.9 0.5 

2,000 — — — — 7.5 3.3 0.9 

2,500 — — — — 11.8 5.2 1.3 

3,000 — — — — 16.9 7.5 1.9 

4,000 — — — — — 13.2 3.4 

5,000 — — — — — 20.7 5.4 

6,000 — — — — — — 7.7 

7,000 — — — — — — 10.5 

8,000 — — — — — — 13.8 

9,000 — — — — — — 17.4 

PIPING PRESSURE LOSSES FOR LOW PRESSURE NATURAL GAS 


Scfh 

Nat. Gas 2-1/2" 3" 4" 6" 8" 

2,000 0.3 — — — — 

2,500 0.5 — — — — 

3,000 0.8 0.3 — — — 

4,000 1.3 0.4 — — — 

5,000 2.1 0.7 — — — 

6,000 3.0 1.0 — — — 

7,000 4.1 1.4 0.3 — — 

8,000 5.4 1.8 0.4 — — 

9,000 6.8 2.3 0.6 — — 

10,000 8.4 2.8 0.7 — — 

12,000 12.1 4.0 1.0 — — 

14,000 16.4 5.5 1.4 — — 

16,000 — 7.2 1.8 — — 

18,000 — 9.1 2.2 0.3 — 

20,000 — 11.2 2.8 0.3 — 

22,000 — 13.6 3.3 0.4 — 

24,000 — 16.1 4.0 0.4 — 

26,000 — 18.9 4.7 0.5 — 

28,000 — — 5.4 0.6 — 

30,000 — — 6.2 0.7 — 

35,000 — — 8.5 1.0 — 

40,000 — — 11.0 1.2 0.3 

45,000 — — 14.0 1.6 0.3 

50,000 — — 17.3 2.0 0.4 

55,000 — — 20.9 2.4 0.5 

60,000 — — — 2.8 0.6 

70,000 — — — 3.8 0.8 

13 

Inches w.c. 

per 100 ft 

Scfh of Schedule 40 pipe 

Nat. Gas 6" 8" 

80,000 5.0 1.1 

90,000 6.3 1.4 

100,000 7.8 1.7 

110,000 9.4 2.1 

120,000 11.2 2.4 

130,000 13.2 2.9 

140,000 15.3 3.3 

150,000 17.6 3.8 

200,000 — 6.8 

250,000 — 10.6 

300,000 — 15.3

HIGH PRESSURE (COMPRESSIBLE) FLOW OF 

NATURAL GAS IN PIPES 

Flows in table are scfh of 0.6 sp. gr. natural gas 

Pipe Inlet Pressure Drop Per 100 Equivalent Feet of 

Size, Pressure, Pipe as a Percentage of Inlet Pressure 

Inches PSIG 2% 4% 6% 8% 10% 

2 340 480 590 680 760 

5 590 840 1030 1180 1320 

1 10 930 1320 1610 1850 2070 

20 1570 2210 2700 3110 3470 

50 3380 4770 5820 6690 7450 

2 710 1010 1230 1420 1590 

5 1230 1740 2130 2450 2740 

1-1/4 10 1950 2760 3370 3880 4330 

20 3260 4600 5620 6470 7210 

50 7040 9910 12,090 13,910 15,490 

2 1080 1530 1870 2160 2410 

5 1860 2630 3220 3710 4140 

1-1/2 10 2940 4160 5080 5850 6530 

20 4930 6960 8490 9780 10,900 

50 10,640 15,000 18,290 21,040 23,430 

2 2100 2980 3640 4200 4700 

5 3630 5120 6270 7230 8070 

2 10 5740 8090 9890 11,400 12,720 

20 9610 13,550 16,540 19,050 21,230 

50 20,720 29,190 35,610 40,960 45,610 

2 3390 4810 5880 6780 7580 

5 5850 8260 10,100 11,650 13,010 

2-1/2 10 9240 13,040 15,940 18,370 20,500 

20 15,480 21,840 26,660 30,700 34,220 

50 33,400 47,050 57,400 66,010 73,510 

2 6060 8590 10,500 12,120 13,540 

5 10,450 14,760 18,050 20,820 23,240 

3 10 16,510 23,290 28,480 32,810 36,610 

20 27,650 38,990 47,620 54,820 61,110 

50 59,640 84,010 102,500 117,880 131,270 

2 12,480 17,690 21,620 24,960 27,890 

5 21,520 30,400 37,180 42,890 47,880 

4 10 34,000 47,980 58,650 67,580 75,410 

20 56,960 80,320 98,090 112,930 125,880 

50 122,850 173,070 211,140 242,840 270,420 

2 37,250 52,800 64,560 74,510 83,270 

5 64,240 90,760 111,010 128,040 142,950 

6 10 101,520 143,260 175,120 201,780 225,150 

20 170,060 239,810 292,840 337,150 375,820 

50 366,770 516,680 630,360 724,970 807,320 

EQUIVALENT LENGTHS OF STANDARD PIPE FITTINGS & VALVES 

VALVES FULLY OPEN 

Pipe I.D. Swing 90° 45° 90° Tee, Flow 90° Tee, Flow 

Size Inches Gate Globe Angle Check Elbow Elbow Through Run Through Branch 

1/2" 0.622 0.35 18.6 9.3 4.3 1.6 0.78 1.0 3.1 

3/4" 0.824 0.44 23.1 11.5 5.3 2.1 0.97 1.4 4.1 

1" 1.049 0.56 29.4 14.7 6.8 2.6 1.23 1.8 5.3 

1-1/4" 1.380 0.74 38.6 19.3 8.9 3.5 1.6 2.3 6.9 

1-1/2" 1.610 0.86 45.2 22.6 10.4 4.0 1.9 2.7 8.0 

2" 2.067 1.10 58 29 13.4 5.2 2.4 3.5 10.4 

2-1/2" 2.469 1.32 69 35 15.9 6.2 2.9 4.1 12.4 

3" 3.068 1.60 86 43 19.8 7.7 3.6 5.1 15.3 

4" 4.026 2.1 112 56 26.8 10.1 5.4 6.7 20.1 

6" 6.065 2.6 140 70 40.4 15.2 8.1 10.1 30.3 

Equivalent lengths are for standard screwed fittings and for screwed, flanged, or welded valves relative to 

schedule 40 steel pipe. 

14

SIMPLIFIED SELECTION OF AIR, GAS AND MIXTURE PIPING SIZE 

Air, gas and mixture piping systems should be sized to 

deliver flow at a uniform pressure distribution and without 

excessive pressure losses in transit. 

Two factors cause air pressure loss and consequent pressure 

variations: 

1) Friction in piping and bends, and 

2) Velocity pressure losses due to changes in direction. 

In combustion work, piping runs are usually short (under 

50 ft.), but often have many bends. By assuming that all 

velocity pressure is lost or dissipated at each change of direction 

and by using a pipe size to give a very low velocity pressure, 

other losses can be disregarded. In general, a velocity 

pressure of 0.3 to 0.5″ w.c. satisfies this need. This is equivalent 

to air velocities of about 2200 to 2800 ft/minute. For 

other gases, this velocity is inversely proportional to their 

gravities; consequently, higher velocities can be tolerated 

with natural gas, but propane and butane piping should be 

sized for lower velocities than air. 

The accuracy of orifice meters is also sensitive to pipe 

velocity, so every effort should be made to keep velocity pressure 

below 0.3″ w.c. in metering runs. 

Pv, "wc 

Nat. Pro- 

Velocity 

Bu- Ft/Min 

Pipe Size 

2-1/2" 

1-1/2" 

Gas Air panetane x1000 

10 

1/4" 3/8" 1/2" 3/4" 1" 1-1/4" 2" 3" 

3.0 5.0 

4.0 

9 

8 

2.0 

1.5 

1.0 

3.0 

2.0 

1.5 

5.0 

4.0 

3.0 

2.0 

5.0 

4.0 

3.0 

7 

6 

5 

1.0 1.5 

2.0 4 

1.0 

1.5 

1.0 

3 

2.5 

0.5 

0.4 

0.3 

0.2 

0.15 

0.1 

0.5 

0.4 

0.3 

0.2 

0.15 

0.5 

0.4 

0.3 

0.2 

0.5 

0.4 

0.3 

0.1 0.15 0.2 

0.05 

0.1 0.15 

1 

Shaded Areas 

100 

Indicate Recommended 

Velocity Pressure 

Range 

2 

1.5 

2 3 4 6 8 1000 

If pipe sizing charts or tables aren’t available, you can 

quickly estimate the maximum air flow capacity of a pipe 

with these simple equations: 

Maximum cfh air = (Nominal pipe size) 2 x 1000 

The result will correspond to a velocity pressure of about 0.5″ 

w.c., the maximum recommended for low pressure air systems. 

Optimum cfh air = (Nominal pipe size) 2 x 750 

QUICK METHOD FOR SIZING AIR PIPING 

15 

The graph below shows the relationship between velocity, 

velocity pressure and flow for various pipe sizes handling air, 

natural gas, propane, and butane. Because the specific gravity 

of most air-gas mixtures is close to that of air, mixture piping 

can be sized the same as air piping. The error will be 

insignificant. 

Example: A burner requires 10,000 cfh air at a static pressure 

of 13″ w.c. The blower supplying this burner develops 15″ 

w.c. static pressure. Piping between the two will run 15 feet, 

including four 90° bends. What size piping is required? 

Solution: Total pressure available for piping losses is 

15″ w.c. - 13 ″ w.c. = 2″ w.c. 

This allows a velocity pressure loss of: 

2 ÷ 4 = 0.5″ w.c. for each of the four elbows. 

Under the “Air” column on the left-hand side of the Pv 

graph, locate 0.5″ w.c. velocity pressure. This is equivalent to 

about 2800 ft/minute air velocity. Locate the intersection of 

the 2800 ft/minute line and the 10,000 cfh line, then drop 

down to the first curve below this point, in this case, 4″ pipe. 

This is the pipe size that should be used. 

12" 14" 16" 

2 3 4 6 8 10,000 2 3 4 6 8 100,000 2 3 4 6 8 

Flow, cfh 

4" 

This will produce a flow rate equivalent to about 0.3″ w.c. 

velocity pressure. 

Example: What is the maximum air flow rate for 21 ⁄ 2" pipe? 

(21 ⁄ 2) 2 = 6.25 

6.25 x 1000 = 6,250 cfh air. 

6" 

8" 

10" 

18" 

10 

9 

8 

7 

6 

5 

4 

3 

2.5 

2 

1.5 

1

SIZING BRANCH PIPING BY THE EQUAL AREA METHOD 

The equal area method of sizing pipe manifolds is based on 

maintaining constant total cross-sectional area in all portions of 

a piping train, regardless of the number of branches in each portion. 

In the sketch below, the equal area method requires that: 

Area of X = 2 times area of Y = 6 times area of Z. 

X 

Y Y 

Z Z Z Z Z Z 

The advantage of this method is that once the size of the 

smallest branch has been determined, via velocity pressures or 

any other valid method, the remainder of the piping system 

can be correctly sized without any additional calculations. 

Remember, however, that if the calculation of the smallest 

branches is in error, the entire system will be incorrectly sized. 

Cv, flow factor, is defined as the full flow capacity of a 

valve expressed in gpm of 60°F water at 1 psi pressure drop. 

This rating is determined by actual flow test. To convert Cv to 

actual flow capacity for gases, use the graph below. 

Locate Cv at the left, read across to the appropriate curve and 

then down to obtain flow capacity at 1″ w.c. pressure drop. 

For drops other than 1″ w.c., multiply the flow by the square 

root of the pressure drop. 

C v Flow Factor 

1000 

8 

6 

4 

3 

2 

100 

8 

6 

4 

3 

2 

10 

8 

6 

4 

3 

2 

C v FLOW FACTOR CONVERSIONS 

16 

To use the table below, read across from the pipe size of the 

smallest branch in the manifold (Z in the sketch at left) and 

down from the number of these branches. At the intersection, 

find the recommended size pipe to feed these branches. For 

example, if Z is 3/4", Y should be 1 1 ⁄4" and X should be 2" pipe. 

Size of 

Branch 

Connection 

PROPANE 1.5 SP GR 

Flow, SCH @ 1" W.C. ∆P @ 14.7 PSIA & 60˚ F 

Number of Branch Connections 

1 2 3 4 5 6 7 8 

1/4 1/4 3/8 1/2 3/4 3/4 1 1 1 

3/8 3/8 3/4 3/4 1 1-1/4 1-1/4 1-1/4 1-1/4 

1/2 1/2 3/4 1 1 1 1-1/4 1-1/2 2 

3/4 3/4 1-1/4 1-1/4 1-1/2 2 2 2 2-1/2 

1 1 1-1/4 2 2 2-1/2 2-1/2 3 3 

1-1/4 1-1/4 2 2-1/2 3 3 4 4 4 

1-1/2 1-1/2 2-1/2 3 3 4 4 4 6 

2 2 3 4 4 6 6 6 6 

2-1/2 2-1/2 4 4 6 6 6 6 6 

3 3 4 6 6 8 8 8 8 

4 4 6 8 8 10 10 10 12 

6 6 8 10 12 14 16 18 18 

8 8 12 14 16 18 20 20 or 24 24 

10 10 14 18 20 24 24 30 30 

For conditions other than 14.7 psia and 60°F, use this formula: 

Q = 1360Cv (P 1-P 2) P 2, 

GT 

where 

Q = SCFH 

P 1 = Inlet pressure, psia 

P 2 = Outlet pressure, psia 

T = Absolute flowing temperature (°F + 460) 

G = Specific gravity of gas 

BUTANE 2.0 SP GR 

AIR 1.0 SP GR 

NATURAL GAS 0.6 SP GR 

PROPANE - AIR 

1.29 SP GR 

1 

10 20 30 40 60 80 100 2 3 4 6 8 1000 2 3 4 6 8 10,000 2 3 4 6

The total pressure of an air stream flowing in a duct is the 

sum of the static or bursting pressure exerted upon the sidewalls 

of the duct and the impact or velocity pressure of the 

moving air. Through the use of a pitot tube connected differentially 

to a manometer, the velocity pressure alone is indicated 

and the corresponding air velocity determined. 

For accuracy of plus or minus 2%, as in laboratory applications, 

extreme care is required and the following precautions 

should be observed: 

1. Duct diameter 4" or greater. 

2. Make an accurate traverse per sketch below and average the 

readings. 

3. Provided smooth, straight duct sections 10 diameters in 

length both upstream and downstream from the pitot tube. 

4. Provide an egg crate type straightener upstream from the 

pitot tube. 

Air Velocity in Feet Per Minute 

13000 

12000 

11000 

10000 

9000 

8000 

7000 

6000 

5000 

4000 

3000 

2000 

1000 

0 0 

DUCT VELOCITY & FLOW MEASUREMENTS 

D 

.35D 

.60D 

.80D 

.92D 

17 

In making an air velocity check select a location as suggested 

above, connect tubing leads from both pitot tube connections to 

the manometer and insert in the duct with the tip directed into the 

air stream. If the manometer shows a minus indication reverse the 

tubes. With a direct reading manometer, air velocities will now be 

shown in feet per minute. In other types, the manometer will read 

velocity pressure in inches of water and the corresponding velocity 

will be found from the curves below. If circumstances do not 

permit an accurate traverse, center the pitot tube in the duct, 

determine the center velocity and multiply by a factor of .9 for the 

approximate average velocity. Field tests run in this manner 

should be accurate within plus or minus 5%. 

The velocity indicated is for dry air at 70°F., 29.9" Barometric 

Pressure and a resulting density of .075#/ cu. ft. For air at a temperature 

other than 70°F. refer to the curves below. For other 

variations from these conditions, corrections may be based 

upon the following data: 

Air Velocity = 1096.2 Pv 

D 

where Pv = velocity pressure in inches of water 

D = Air density in #/cu. ft. 

Air Density = 1.325 x PB 

T 

where PB= Barometric Pressure in inches of mercury 

T = Absolute Temperature (indicated temperature 

plus 460) 

Flow in cu. ft. per min. = Duct area in square feet x air 

velocity in ft. per min. 

1400° 

.2 .4 .6 .8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6 2.8 3.0 3.2 3.4 3.6 3.8 4.0 

1200° 

1000° 

Gage Reading with Pilot Tube (Velocity Pressure) in Inches of Water 

REPRINTED WITH PERMISSION OF F.W. DWYER MANUFACTURING CO., MICHIGAN CITY, INDIANA 

600° 

300° 

100° 

70° 

800° 

400° 

200° 

40°

CHAPTER 2 – FAN LAWS & BLOWER 

Combustion air blowers are normally rated in terms of standard 

cubic feet (scf) of air; that is, 70°F air at Sea Level 

(29.92" Hg) barometric pressure. Density of this air is 0.075 

lb/cu ft, and its specific gravity is 1.0. 

Although fuel/air ratios are usually stated in cubic feet of air 

per cubic foot or gallon of fuel, it’s the weight of air per 

weight of fuel that’s important. As long as air temperature and 

pressure are close to standard conditions, blower and burner 

sizing charts can be used without correction. However, if air 

temperature, gauge pressure or altitude change the density of 

air by any significant amount, blower ratings have to be corrected 

from actual cubic feet (acf) to standard cubic feet to 

insure the proper weight flow of air reaches the burner. 

Centrifugal fans are basically constant volume devices; at a 

given rotational speed, they will deliver the same volume of 

air regardless of its density. 

APPLICATION ENGINEERING 

18 

RPM 

"R" 

Volume 

"V" 

For blower wheel with eight segments, Theoretical Flow = 8 x V x R 

If, for example, a blower has a wheel made up of eight segments, 

each with a volume V, and the wheel is rotating at R 

rpm, the theoretical flow rating of the blower will be 8 x V x 

R, because each fan wheel segment fills with air and empties 

itself once each revolution. 

The actual volume delivered is strictly a function of the carrying 

capacity of the wheel and its speed. Cfm, whether it is 

standard (scfm) or actual (acfm) is the same. Consequently, if 

the density of air is reduced by temperature, pressure, or both, 

the blower will deliver a lower weight flow of air, even 

though the measured volume hasn’t changed. 

Air density also affects the pressure developed by the blower 

and its power consumption. Because air density is related to 

temperature, pressure, and altitude (barometric pressure) – see 

pages 20 and 21 – it is possible to relate blower performance to 

these factors with a set of realtionships known as fan laws.

1.Effect of Blower Speed on Flow, Pressure and Power 

Consumption 

a. Flow vs. Speed: The flow rate (V) changes in direct 

ratio to the speed (S) 

V2 = S2 

V1 S1 

Example:Ablower operating at 1750 rpm (S1) delivers 

1000 cfm (V1). How many cfm (V2) will it deliver 

if speed is increased to 3500 rpm (S2)? 

V2 =V1 x S2 = 1000 x 3500 = 2000 cfm 

S 1750 

1 

b. Pressure vs. Speed:The pressure (P) changes as the 

square of the speed ratio (S) 

( ) 

P2 = S2 

P1 S1 

2 

Example:Ablower operating at 1750 rpm (S1) develops 

1 psig (P1) pressure. If speed is doubled to 3500 

rpm (S2), what is the new pressure (P2)? 

P2 =P1 x S2 2 

= 1 x 

3500 2 

( ) ( 1750 ) 

S 1 

= 1 x (2) 2 =1 x 4 = 4 psig 

c. Horsepower vs. Speed:The horsepower (HP) consumedchanges 

as the cube of the speed ratio (S) 

HP2 S2 

= 3 

( ) 

HP1 S1 

Example:Ablower operating at 1750 rpm (S1) requires 

a 5 hp (HP1) motor. How many horsepower (HP2) will 

be required to handle a speed increase to 3500 rpm (S2)? 

S 3 

2 

HP2 =HP1 = 5 x 3500 3 

( ) ( 1750 ) 

S 1 

=5 x (2) 3 =5 x 8 = 40 hp 

Laws 1a, 1b and 1c are known as the 1-2-3 ruleof centrifugal 

blowers. Volume increases in direct ratio, pressure as the 

square, and horsepower as the cube, of the speed ratio. 

Re-rating blowers for nonstandard conditions 

As fan laws 2b, 2c, and 2d show, blower weight flow, 

pressure, and horsepower all change in direct proportion to 

air density or gravity. While these relationships are important 

to know, it’s usually more important to know how to 

select a blower to compensate for nonstandard conditions. 

The following example shows how it is done. 

Example:Aburner is rated a 1 million Btu/hr. at an air pressure 

of 20"w.c., including piping and control valve drops. If 

the burner is to be installed at 6000 feet altitude, select a 

blower that will permit the burner’s input rating to be maintained. 

Solution: Use the rule-of-thumb of 100 Btu per standard 

cubic foot of air to estimate blower flow requirements: 

1,000,000 Btu/hr ÷ 100 Btu/scf air = 10,000 scfh air. 

This is the blower’s standard (sea level) rating. 

At 6,000 feet, the specific gravity of air is 0.80 (see page 20). 

To maintain a weight flow of air through the burner 

equivalent to 10,000 scfh, the volume flow through the 

burner has to be increased to offset the air’s lower density. 

FAN LAWS 

19 

2.Effect of Air Density on Flow, Pressure, and Power 

Consumption. 

a. Volume Flow vs. Density 

Volume flow (cfm) remains constant regardless of density. 

b. Weight Flow vs. Density:Weight flow (W) changes 

in direct ratio to the density (D) or specific gravity (G) 

W2 D2 G2 

= = 

W1 D1 G1 

Example:Ablower delivers 1500 lb/hr (20,000 cu ft/hr) 

(W1) of air at standard conditions (density D1 =0.075 

lb/cu ft). What will be the weight flow delivered if the air 

temperature is 250°F? 

From page 21, air density (D 2) at 250°F is .056 lb/cu ft. 

W2 =W1 x D2 =1500 x .056 =1120 lb/hr. 

D1 .075 

c. Pressure vs. Density:Pressure (P) changes in direct 

proportion to density (D) or specific gravity (G). 

P2 = D2 = G2 

P1 D1 G1 

Example: At sea level conditions (G1 =1.0), a blower 

develops 28" w.c. pressure (P1). What pressure (P2) will it 

develop at 4000 ft. altitude? 

From page 20, air gravity (G 2) at 4000 ft is 0.86. 

P2 =P1 x G2 =28 x .86 =24.1" w.c. 

G1 1.0 

d. Horsepower vs. Density:Horsepower (HP) consumed 

changes in direct proportion to density (D) or specific 

gravity (G). 

HP2 = D2 = G2 

HP1 D1 G1 

Example: Astandard air (G1) blower requires a 10 hp 

(HP1) motor. What horsepower (HP2) is required if this 

blower is to handle a gas of 0.5 specific gravity (G2)? 

The gravity of standard air is 1.0, so 

HP2 =HP1 x G2 =10 x 0.5 =5 hp 

G1 1.0 

V2 = V1 x G1 = 10,000 cfh x 1.00 = 12,500 cfh 

G2 

0.80 

In other words, 12,500 cfh air at 6000 feet has the same 

weight as 10,000 cfh at sea level. 

The pressure required now will be adjusted for the new air 

flow, taking into account the lower density of the air. 

P2 = P1 x V2 

2 2 

V2 

( ) ( ) 

= G1 

V1 V1 G2 P2 = P1 x G1 = 20"w.c. x 1.00 = 25"w.c. 

G2 

0.80 

Because the pressure generated by the blower decreases 

with air density, the sea level pressure rating has to be higher 

to compensate for the loss of outlet pressure at higher altitudes. 

P1 = P2 x G1 = 25"w.c. x 1.00 = 31.25"w.c. 

G2 

0.80 

Therefore, the blower must be capable of delivery at least 

12,500 cfh at 31.25"w.c. at sea level to satisfy the needs of 

the burner at 6000 feet altitude.

Blower horsepower requirements 

Blower horsepower increases with the air flow delivered 

and the pressure developed. The four equations below can be 

used to predict blower horsepower consumption. They differ 

only in the flow and pressure units used. The term “efficiency” 

is the overall blower efficiency – a composite of fan, 

motor and drive train efficiencies – expressed as a decimal. 

hp = 

scfm x "w.c. 

hp = 

scfm x osi 

6356 x efficiency 3670 x efficiency 

hp = 

scfh x "w.c. 

hp = 

scfh x osi 

381,360 x efficiency 220,200 x efficiency 

THE EFFECT OF PRESSURE ON AIR 

Basis: 70°F dry air at sea level 

(29.92" Hg) barometric pressure 

Gauge Absolute Specific 

Pressure, Pressure, Density Specific Volume 

PSIG PSIA Lb./Cu. Ft. Gravity Cu. Ft./Lb. 

0 14.7 0.07500 1.000 13.33 

1 15.7 0.08010 1.068 12.48 

2 16.7 0.08520 1.136 11.74 

3 17.7 0.09031 1.204 11.07 

4 18.7 0.09541 1.272 10.48 

5 19.7 0.10051 1.340 9.95 

10 24.7 0.12602 1.680 7.94 

15 29.7 0.15153 2.020 6.60 

20 34.7 0.17704 2.361 5.65 

25 39.7 0.20255 2.701 4.94 

30 44.7 0.22806 3.041 4.38 

35 49.7 0.25357 3.381 3.94 

40 54.7 0.27908 3.721 3.58 

45 59.7 0.30459 4.061 3.28 

50 64.7 0.33010 4.401 3.03 

60 74.7 0.38112 5.082 2.62 

70 84.7 0.43214 5.762 2.31 

80 94.7 0.48316 6.442 2.07 

90 104.7 0.53418 7.122 1.87 

100 114.7 0.58520 7.802 1.71 

125 139.7 0.71276 9.503 1.40 

150 164.7 0.84031 11.204 1.19 

175 189.7 0.96786 12.905 1.03 

200 214.7 1.09541 14.605 0.91 

250 264.7 1.35051 18.007 0.74 

300 314.7 1.60561 21.408 0.62 

400 414.7 2.11582 28.211 0.47 

500 514.7 2.62602 35.014 0.38 

20 

Blowers used as suction fans 

When a blower is used as a suction device discharging to 

atmosphere, the amount of suction or vacuum developed can 

be calculated from this relationship: 

( ) 

V = P – P2 x 27.7, where 

B + P 

V = suction or vacuum, " w.c. 

P = Absolute atmospheric pressure, psia, at the location where 

the blower is operated 

B = Rated blower discharge pressure, psig (psig = " w.c. ÷ 27.7) 

Example: A blower with a catalog pressure rating of 21" w.c. 

is used as a suction fan on an installation at 1500 ft altitude. 

How much suction will it develop? 

P at 1500 ft = 13.9 psia (from table below) 

B = 21 ÷ 27.7 = .76 psig 

V = 13.9 - (13.9)2 

( ) x 27.7 = 20 "w.c. 

.76 + 13.9 

THE EFFECT OF ALTITUDE ON AIR 

Basis: 70°F dry air at sea level 

(29.92" Hg) barometric pressure 

Specific 

Altitude Barometric Pressure, Density Specific Volume 

Ft. "Hg PSIA Lb./Cu. Ft. Gravity Cu. Ft./Lb. 

0 29.92 14.7 .07500 1.00 13.33 

500 29.38 14.4 .07365 .98 13.58 

1000 28.86 14.2 .07234 .96 13.82 

1500 28.33 13.9 .07101 .95 14.08 

2000 27.82 13.7 .06974 .93 14.34 

2500 27.31 13.4 .06846` .91 14.61 

3000 26.81 13.2 .06720 .90 14.88 

3500 26.32 12.9 .06598 .88 15.16 

4000 25.84 12.7 .06477 .86 15.44 

4500 25.36 12.5 .06357 .85 15.73 

5000 24.89 12.2 .06239 .83 16.03 

5500 24.43 12.0 .06124 .82 16.33 

6000 23.98 11.8 .06011 .80 16.64 

6500 23.53 11.6 .05898 .79 16.95 

7000 23.09 11.3 .05788 .77 17.28 

7500 22.65 11.1 .05678 .76 17.61 

8000 22.22 10.9 .05570 .74 17.95 

8500 21.80 10.7 .05465 .73 18.30 

9000 21.38 10.5 .05359 .71 18.66 

9500 20.98 10.3 .05259 .70 19.01 

10000 20.58 10.1 .05159 .69 19.38 

15000 16.88 8.29 .04231 .56 23.63 

20000 13.75 6.76 .03447 .46 29.01 

Helpful conversions: 

Altitude in meters x 3.28 = Altitutde in feet 

Barometric pressure in "Hg ÷ 2.036 = Barometric pressure 

in psia.

Absolute Specific 

Temp. Temp. Density Specific Volume 

°F Ratio Lb./Cu. Ft. Gravity Cu. Ft./Lb. 

-60 .7547 .09938 1.325 10.06 

-40 .7925 .09464 1.262 10.57 

-30 .8113 .09244 1.233 10.82 

-20 .8302 .09034 1.205 11.07 

-10 .8491 .08833 1.178 11.32 

0 .8679 .08641 1.152 11.57 

20 .9057 .08281 1.104 12.08 

40 1.019 .07361 .981 13.58 

60 .9811 .07644 1.019 13.08 

70 1.000 .07500 1.000 13.33 

80 .9434 .07361 1.060 12.58 

90 1.038 .07227 .964 13.84 

100 1.057 .07098 .946 14.09 

110 1.075 .06974 .930 14.34 

120 1.094 .06853 .914 14.59 

130 1.113 .06737 .898 14.84 

140 1.132 .06624 .883 15.09 

150 1.151 .06516 .869 15.35 

160 1.170 .06411 .855 15.60 

170 1.189 .06310 .841 15.85 

180 1.208 .06211 .828 16.10 

190 1.226 .06115 .815 16.35 

200 1.245 .06023 .803 16.60 

210 1.264 .05933 .791 16.86 

220 1.283 .05846 .779 17.11 

230 1.302 .05761 .768 17.36 

240 1.321 .05679 .757 17.61 

250 1.340 .05599 .747 17.86 

260 1.358 .05521 .736 18.11 

270 1.377 .05445 .726 18.36 

280 1.396 .05372 .716 18.62 

290 1.415 .05300 .707 18.87 

300 1.434 .05230 .697 19.12 

310 1.453 .05162 .688 19.37 

320 1.472 .05096 .679 19.62 

330 1.491 .05032 .671 19.87 

340 1.509 .04969 .663 20.13 

350 1.528 .04907 .654 20.38 

360 1.547 .04848 .646 20.63 

370 1.566 .04789 .639 20.88 

380 1.585 .04732 .631 21.13 

390 1.604 .04676 .623 21.38 

400 1.623 .04622 .616 21.64 

410 1.642 .04569 .609 21.89 

420 1.660 .04517 .602 22.14 

430 1.679 .04466 .595 22.39 

440 1.698 .04417 .589 22.64 

450 1.717 .04368 .582 22.89 

460 1.736 .04321 .576 23.14 

470 1.755 .04274 .570 23.40 

480 1.774 .04229 .564 23.65 

490 1.792 .04184 .558 23.90 

500 1.811 .04141 .552 24.15 

510 1.830 .04098 .546 24.40 

THE EFFECT OF TEMPERATURE ON AIR 

Basis: 70°F dry air at sea level (29.92" Hg) barometric pressure 

Explanation of terms: 

Absolute Temperature Ratio: Temperature, °F + 460 

530 

Specific Gravity: Density at stated temperature 

.07500 

Specific Volume: 1 

Density, lb/cu. ft. 

21 

Absolute Specific 

Temp. Temp. Density Specific Volume 

°F Ratio Lb./Cu. Ft. Gravity Cu. Ft./Lb. 

520 1.849 .04056 .541 24.65 

530 1.868 .04015 .535 24.91 

540 1.887 .03975 .530 25.16 

550 1.906 .03936 .525 25.41 

560 1.925 .03897 .520 25.66 

570 1.943 .03859 .515 25.91 

580 1.962 .03822 .510 26.16 

590 1.981 .03786 .505 26.42 

600 2.000 .03750 .500 26.67 

610 2.019 .03715 .495 26.92 

620 2.038 .03681 .491 27.17 

630 2.057 .03647 .486 27.42 

640 2.075 .03614 .482 27.67 

650 2.094 .03581 .477 27.92 

660 2.113 .03549 .473 28.18 

670 2.132 .03518 .469 28.43 

680 2.151 .03487 .465 28.68 

690 2.170 .03457 .461 28.93 

700 2.189 .03427 .457 29.18 

710 2.208 .03397 .453 29.43 

720 2.226 .03369 .449 29.69 

730 2.245 .03340 .445 29.94 

740 2.264 .03313 .442 30.19 

750 2.283 .03285 .438 30.44 

760 2.302 .03258 .434 30.69 

770 2.321 .03232 .431 30.94 

780 2.340 .03206 .427 31.19 

790 2.358 .03180 .424 31.45 

800 2.377 .03155 .421 31.70 

825 2.425 .03093 .412 32.33 

850 2.472 .03034 .405 32.96 

875 2.519 .02978 .397 33.58 

900 2.566 .02923 .390 34.21 

925 2.613 .02870 .383 34.84 

950 2.660 .02819 .376 35.47 

975 2.708 .02770 .369 36.10 

1000 2.755 .02723 .363 36.73 

1025 2.802 .02677 .357 37.36 

1050 2.849 .02623 .350 37.99 

1100 2.943 .02548 .340 39.25 

1150 3.033 .02469 .329 40.50 

1200 3.132 .02395 .319 41.76 

1250 3.226 .02325 .310 43.02 

1300 3.321 .02259 .301 44.28 

1350 3.415 .02196 .293 45.53 

1400 3.509 .02137 .285 46.79 

1500 3.698 .02028 .270 49.31 

1600 3.887 .01930 .257 51.81 

1700 4.075 .01840 .245 54.35 

1800 4.264 .01759 .235 56.85 

1900 4.453 .01684 .225 59.38 

2000 4.642 .01616 .215 61.88 

2100 4.830 .01553 .207 64.39 

2200 5.019 .01494 .199 66.93

CHAPTER 3 – GAS 

PHYSICAL PROPERTIES OF COMMERCIAL FUEL GASES 

Constituents – % by Volume Density, Specific 

Specific Lb per Volume 

No. Gas CH4 C2H6 C3H8 C4H10 CO H2 CO2 O2 N2 Gravity Cu Ft Cu Ft/Lb 

1 

2 

Acetylene 

Blast Furnace Gas 

– 

– 

– 

– 

– 

– 

(100% C2H2 ) 

– 27.5 1 

– 

11.5 

– 

– 

– 

60 

0.91 

1.02 

.07 

.078 

14.4 

12.8 

3 Butane (natural gas) – – 7 93 – – – – – 1.95 .149 6.71 

4 Butylene (Butene) – – – (100% C4H8 ) – – – 1.94 .148 6.74 

5 Carbon Monoxide – – – – 100 – – – – 0.97 .074 13.5 

6 

7 

8 

Carburetted Water Gas 

Coke Oven Gas 

Digester (Sewage) Gas 

10.2 

32.1 

67 

(6.1% C2H4 , 2.8% C6H6 ) 

(3.5% C2H4 , 0.5% C6H6 ) 

– – (8% H2O) 34 

6.3 

40.5 

46.5 

– 

3 

2.2 

25 

0.5 

0.8 

– 

2.9 

8.1 

– 

0.63 

0.44 

0.80 

.048 

.034 

.062 

20.8 

29.7 

16.3 

9 Ethane – 100 – – – – – – – 1.05 .080 12.5 

10 Hydrogen – – – – – 100 – – – 0.07 .0054 186.9 

11 Methane 100 – – – – – – – – 0.55 .042 23.8 

12 Natural (Birmingham, AL) 90 5 – – – – – – 5 0.60 .046 21.8 

13 Natural (Pittsburgh, PA) 83.4 15.8 – – – – – – 0.8 0.61 .047 21.4 

14 Natural (Los Angeles, CA) 77.5 16.0 – – – – 6.5 – – 0.70 .054 18.7 

15 Natural (Kansas City, MO) 84.1 6.7 – – – – 0.8 – 8.4 0.63 .048 20.8 

16 Natural (Groningen, 

Netherlands) 

81.3 2.9 0.4 0.1 – – 0.9 – 14.4 0.64 .048 20.7 

17 Natural (Midlands Grid, U.K.) 91.8 3.5 0.8 0.3 – – 0.4 – 2.8 0.61 .046 21.8 

18 Producer (Wellman-Galusha) 2.3 – – – 25 14.5 4.7 – 52.7 0.84 .065 15.4 

19 Propane (natural gas) – – 100 – – – – – – 1.52 .116 8.61 

20 

21 

Propylene (Propene) 

Sasol (South Africa) 

– 

26 

– 

– 

– (100% C3H6 ) 

– – 22 48 

– 

– 

– 

0.5 

– 

1 

1.45 

0.42 

.111 

.032 

9.02 

31.3 

22 Water Gas (bituminous) 4.6 (0.4% C2H4 , 0.3% C6H6 ) 28.2 32.5 5.5 0.9 27.6 0.71 .054 18.7 

COMBUSTION PROPERTIES OF COMMERCIAL FUEL GASES 

Air/Gas Ratio, Flammability Limits, Ignition Temperature & Flame Velocity 

Stoichiometric 

Limits of 

Flammability Minimum Maximum 

Air/Gas Ratio % Gas in Ignition Flame Velocity 

Cu Ft Air/ Lb Air/ Air/Gas Mixture Temperature in Air, 

No. Gas Cu Ft Gas Lb Gas Lean Rich in Air, °F Ft/Sec* 

1 Acetylene 11.91 13.26 2.5 80 581 9.4 

2 Blast Furnace Gas 0.68 0.67 45 72 – – 

3 Butane (natural gas) 30.47 15.63 1.86 8.41 826 2.8 

4 Butylene (Butene) 28.59 14.77 1.7 9 829 3.2 

5 Carbon Monoxide 2.38 2.46 12 74 1128 2.0 

6 Carburetted Water Gas 4.60 7.36 4.2 42.9 – – 

7 Coke Oven Gas 4.99 11.27 4.5 31.5 – – 

8 Digester (Sewage) Gas 6.41 7.97 8 17 – – 

9 Ethane 16.68 15.98 3.15 12.8 882 2.8 

10 Hydrogen 2.38 33.79 4 74.2 1065 16.0 

11 Methane 9.53 17.23 5 15 1170 2.2 

12 Natural (Birmingham, AL) 9.41 15.68 7.03 15.77 – – 

13 Natural (Pittsburgh, PA) 10.58 17.31 4.6 14.7 – – 

14 Natural (Los Angeles, CA) 10.05 14.26 4.9 15.6 – – 

15 Natural (Kansas City, MO) 9.13 14.59 5.4 16.3 – – 


Netherlands) 

8.41 13.45 6.1 15 1238 1.18 

17 Natural (Midlands Grid, U.K.) 9.8 16.13 5 15 1300 0.98 

18 Producer (Wellman-Galusha) 1.30 1.56 16.4 69.4 – – 

19 Propane (natural gas) 23.82 15.73 2.37 9.50 898 2.7 

20 Propylene (Propene) 21.44 14.77 2 11.1 856 3.3 

21 Sasol (South Africa) 4.13 9.84 5.3 37.4 – – 

22 Water Gas (bituminous) 2.01 2.86 8.9 61 – – 

*Uniform flame speed in a 1" diameter tube. Flame speeds increase in larger diameter tubes. 

22


Heating Value, Heat Release & Flame Temperature 

Heating Value Theoretical 

Heat release, Btu Flame 

Btu/cu ft Btu/lb Temperature 

No. Gas Gross Net Gross Net Per Cu Ft Air Per Lb Air °F 

1 Acetylene 1498 1447 21,569 20,837 125.8 1677 4250 

2 Blast Furnace Gas 92 92 1178 1178 135.3 1804 2650 

3 Butane (natural gas) 3225 2977 21,640 19,976 105.8 1411 3640 

4 Butylene (Butene) 3077 2876 20,780 19,420 107.6 1435 3810 

5 Carbon Monoxide 323 323 4368 4368 135.7 1809 3960 

6 Carburetted Water Gas 550 508 11,440 10,566 119.6 1595 3725 

7 Coke Oven Gas 574 514 17,048 15,266 115.0 1533 3610 

8 Digester (Sewage) Gas 690 621 11,316 10,184 107.6 1407 3550 

9 Ethane 1783 1630 22,198 20,295 106.9 1425 3710 

10 Hydrogen 325 275 61,084 51,628 136.6 1821 3960 

11 Methane 1011 910 23,811 21,433 106.1 1415 3640 

12 Natural (Birmingham, AL) 1002 904 21,844 19,707 106.5 1420 3565 

13 Natural (Pittsburgh, PA) 1129 1021 24,161 21,849 106.7 1423 3562 

14 Natural (Los Angeles, CA) 1073 971 20,065 18,158 106.8 1424 3550 

15 Natural (Kansas City, MO) 974 879 20,259 18,283 106.7 1423 3535 


Netherlands) 

941 849 19,599 17,678 111.9 1492 3380 

17 Natural (Midlands Grid, U.K.) 1035 902 22,500 19,609 105.6 1408 3450 

18 Producer (Wellman-Galusha) 167 156 2650 2476 128.5 1713 3200 

19 Propane (natural gas) 2572 2365 21,500 19,770 108 1440 3660 

20 Propylene (Propene) 2322 2181 20,990 19,630 108.8 1451 3830 

21 Sasol (South Africa) 500 443 14,550 13,016 116.3 1551 3452 

22 Water Gas (bituminous) 261 239 4881 4469 129.9 1732 3510 


Combustion Products & %CO 2 

Combustion Products, Cu Ft/Cu Ft Gas Combustion Products, Lb/Lb Gas Ultimate 

CO2 No. Gas CO2 H2O N2 Total CO2 H2O N2 Total %* 

1 Acetylene 2.00 1.00 9.41 12.41 3.38 0.69 10.19 14.26 17.5 

2 Blast Furnace Gas 0.39 0.02 1.14 1.54 .59 — 1.08 1.67 25.5 

3 Butane (natural gas) 3.93 4.93 24.07 32.93 3.09 1.59 11.95 16.63 14.0 

4 Butylene (Butene) 4.00 4.00 22.59 30.59 3.14 1.29 11.34 15.77 15.0 

5 Carbon Monoxide 1.00 — 1.88 2.88 1.57 — 1.89 3.46 34.7 

6 Carburetted Water Gas 0.76 0.87 3.66 5.29 1.85 0.87 5.64 8.36 17.2 

7 Coke Oven Gas 0.51 1.25 4.02 5.78 1.76 1.76 8.75 12.27 11.2 

8 Digester (Sewage) Gas 0.92 1.42 5.44 7.78 1.74 1.10 6.53 9.37 14.5 

9 Ethane 2.00 3.00 13.18 18.18 2.93 1.8 12.25 16.98 13.2| 

10 Hydrogen — 1.00 1.88 2.88 — 8.89 25.90 34.79 0 

11 Methane 1.00 2.00 7.53 10.53 2.75 2.25 13.23 18.23 11.7 

12 Natural (Birmingham, AL) 1.00 2.02 7.48 10.50 2.54 2.11 12.03 16.68 11.8 

13 Natural (Pittsburgh, PA) 1.15 2.22 8.37 11.73 2.86 2.27 13.18 18.31 12.1 

14 Natural (Los Angeles, CA) 1.16 2.10 7.94 11.20 2.51 1.87 10.88 15.26 12.7 

15 Natural (Kansas City, MO) 0.98 1.95 7.30 10.23 2.39 1.95 11.25 15.59 11.9 


Netherlands) 

0.89 1.73 6.74 9.36 2.17 1.73 10.45 14.35 11.7 

17 Natural (Midlands Grid, U.K.) 1.05 2.19 7.94 11.78 2.67 2.29 12.84 17.80 11.7 

18 Producer (Wellman-Galusha) 0.34 0.17 1.59 2.11 0.61 0.13 1.82 2.56 17.6 

19 Propane (natural gas) 3.00 4.17 18.82 25.99 3.00 1.70 12.03 16.73 13.7 

20 Propylene (Propene) 3.00 3.00 16.94 22.94 3.14 1.29 11.34 15.77 15.0 

21 Sasol (South Africa) 0.48 1.00 3.28 4.76 1.76 1.50 7.63 10.89 12.8 

22 Water Gas (bituminous) 0.41 0.47 1.86 2.74 0.89 0.42 2.55 3.86 18.0 

*In dry flue gas sample 

23

PROPANE/AIR & BUTANE/AIR MIXTURES 

EQUIVALENT BTU TABLES 

PROPANE/AIR MIXTURE BUTANE/AIR MIXTURE 

B.t.u. Specific 

Equivalent 

Propane- 

Air 

Mixture Specific 

Kind of Gas Content Gravity B.t.u. Gravity 

Carbureted Water Gas . . . . . . . . . .517 .65 690 1.14 

Mixed Water and Coke Oven . . . . . .530 .46 855 1.17 

Coke Oven . . . . . . . . . . . . . . . . . . .590 .42 1000 1.20 

Natural . . . . . . . . . . . . . . . . . . . . . .900 .56 1100 1.23 

Natural . . . . . . . . . . . . . . . . . . . . .1050 .60 1400 1.28 

Natural . . . . . . . . . . . . . . . . . . . . .1140 .65 1560 1.32 

B.t.u. Specific 

Equivalent 

Butane- 

Air 

Mixture Specific 

Kind of Gas Content Gravity B.t.u. Gravity 

Carbureted Water Gas . . . . . . . . . .517 .65 708 1.20 

Mixed Water and Coke Oven . . . . . .530 .46 870 1.25 

Coke Oven . . . . . . . . . . . . . . . . . . .590 .42 1058 1.31 

Natural . . . . . . . . . . . . . . . . . . . . . .900 .56 1380 1.41 

Natural . . . . . . . . . . . . . . . . . . . . .1050 .60 1550 1.46 

Natural . . . . . . . . . . . . . . . . . . . . .1140 .65 1680 1.50 

NOTE: The B.t.u. content and specific gravity figures are representative figures and will vary according to area. Therefore, these tables should be used as a guide only. 

MIXTURE SPECIFICATIONS 

PROPANE/AIR MIXTURES BUTANE/AIR MIXTURES 

B.t.u. per Percentage Percentage Percentage Specific Percentage Percentage Percentage Specific 

Cubic Foot of Propane of Air by of Oxygen by Gravity of of Butane of Air by of Oxygen by Gravity of 

of MIxture by Volume Volume Volume (Orsat) the MIxture by Volume Volume Volume (Orsat) the Mixture 

3200 — — — — 100.00 0.00 0.000 1.950 

3150 — — — — 98.44 1.56 0.328 1.935 

3100 — — — — 96.88 3.12 0.656 1.920 

3050 — — — — 95.32 4.68 0.984 1.905 

3000 — — — — 93.75 6.25 1.312 1.891 

2950 — — — — 92.20 7.80 1.643 1.875 

2900 — — — — 90.62 9.38 1.967 1.861 

2850 — — — — 89.08 10.92 2.297 1.846 

2800 — — — — 87.51 12.49 2.625 1.831 

2750 — — — — 85.95 14.05 2.953 1.817 

2700 — — — — 84.38 15.62 3.280 1.802 

2650 — — — — 82.82 17.18 3.612 1.786 

2600 — — — — 81.25 18.75 3.935 1.771 

2550 100.00 0.00 0.000 1.523 79.70 20.30 4.268 1.755 

2500 98.04 1.96 0.409 1.513 78.18 21.82 4.590 1.744 

2450 96.08 3.92 0.819 1.502 76.58 23.42 4.921 1.728 

2400 94.12 5.88 1.288 1.492 75.00 25.00 5.249 1.712 

2350 92.16 7.84 1.639 1.482 73.44 26.56 5.576 1.698 

2300 90.19 9.81 2.050 1.472 71.86 28.14 5.899 1.683 

2250 88.24 11.76 2.458 1.461 70.30 29.70 6.238 1.668 

2200 86.27 13.73 2.869 1.451 68.79 31.21 6.561 1.653 

2150 84.31 15.69 3.279 1.441 67.20 32.80 6.889 1.638 

2100 82.35 17.65 3.688 1.431 65.63 34.37 7.219 1.623 

2050 80.39 19.61 4.098 1.420 64.09 35.91 7.548 1.608 

2000 78.43 21.56 4.506 1.410 62.52 37.48 7.869 1.593 

1950 76.47 23.53 4.918 1.400 60.96 39.04 8.200 1.579 

1900 74.51 25.49 5.317 1.390 59.38 40.62 8.542 1.564 

1850 72.55 27.45 5.737 1.379 57.87 42.13 8.868 1.550 

1800 70.58 29.42 6.149 1.369 56.25 43.75 9.162 1.535 

1750 68.62 31.38 6.558 1.359 54.69 45.31 9.500 1.520 

1700 66.67 33.33 6.964 1349 53.17 46.83 9.850 1.505 

1650 64.70 35.30 7.378 1.338 51.60 48.40 10.180 1.490 

1600 62.74 37.26 7.787 1.328 50.00 50.00 10.488 1.475 

1550 60.78 39.22 8.197 1.318 48.50 51.50 10.817 1.461 

1500 58.82 41.18 8.606 1.308 46.92 53.08 11.130 1.446 

1450 56.86 43.14 9.016 1.297 45.35 54.65 11.490 1.431 

1400 54.90 45.10 9.246 1.287 43.75 56.25 11.810 1.416 

1350 52.94 47.06 9.835 1.277 42.22 57.78 12.130 1.401 

1300 50.98 49.02 10.245 1.267 40.60 59.40 12.481 1.386 

1250 49.02 50.98 10.654 1.256 39.09 60.91 12.795 1.371 

1200 47.06 52.94 11.064 1246 37.50 62.50 13.137 1.356 

1150 45.09 54.91 11.476 1.236 35.92 64.08 13.462 1.340 

1100 43.13 56.87 11.886 1.226 34.38 65.62 13.787 1.326 

1050 41.17 58.83 12.295 1.215 32.80 67.21 14.100 1.312 

1000 39.21 60.79 12.705 1.205 31.25 68.75 14.412 1.296 

950 37.25 62.75 13.115 1.195 29.75 70.25 14.775 1.282 

900 35.29 64.71 13.524 1.185 28.20 71.80 15.100 1.266 

850 33.33 66.67 13.934 1.174 26.55 73.45 15.425 1.252 

800 31.37 68.63 14.344 1.164 25.00 75.00 15.712 1.237 

750 29.41 70.59 14.753 1.154 23.50 76.50 16.081 1.223 

700 27.45 72.55 15.163 1.114 21.88 78.12 16.400 1.206 

650 25.49 74.51 15.573 1.133 20.38 79.62 16.750 1.194 

600 23.53 76.47 15.982 1.123 18.75 81.25 17.081 1.178 

550 21.56 78.44 16.394 1.113 17.25 82.75 17.412 1.163 

500 19.61 80.39 16.892 1.103 15.63 84.37 17.712 1.148 

450 17.65 82.35 17.211 1.092 14.13 85.87 18.081 1.135 

400 15.69 84.31 17.621 1.082 12.50 87.50 18.375 1.120 

350 13.73 86.27 18.031 1.072 11.00 89.00 18.687 1.105 

300 11.76 88.24 18.442 1.062 9.38 90.62 19.031 1.089 

250 9.80 90.20 18.852 1.051 7.75 92.25 19.313 1.074 

200 7.84 92.16 19.261 1.041 6.25 93.75 19.687 1.059 

150 5.88 94.12 19.670 1.031 4.75 95.25 20.000 1.045 

100 3.92 96.08 20.081 1.021 3.13 96.87 20.342 1.029 

24

CHAPTER 4 – OIL 

FUEL OIL SPECIFICATIONS PER ANSI/ASTM D 396-79 A 

Water 

CarbonResidue 

on Distillation Specific Cop- 

Flash Pour and 10% Temperatures, Saybolt Viscosity, sD Kinematic Viscosity, cStD Gravity per 

Point, Point, Sedi- Bot- Ash, °C(°F) 60/60°F Strip Sul- 

°C °C ment, toms, weight 10% Universal at Furol at 50°C At 38°C At 40°C At 50°C (deg Corro- fur, 

Grade of (°F) (°F) vol % % % Point 90% Point 38°C(100°F) 122°F) (100°F) (104°F) (122°F) API) sion % 

Fuel Oil Min Max Max Max Max Max Min Max Min Max Min Max Min Max Min Max Min Max Max Max Max 

No. 1 38 -18C 0.05 0.15 – 215 — 288 — — — — 1.4 2.2 1.3 2.1 — — 0.8499 No. 3 0.5 

A distillate oil (100) 

intended for 

vaporizing pottype 

burners and 

other burners 

requiring this 

grade of fuel 

(0) (420) (550) (35 min) 

No. 2 38 -6C 0.05 0.35 — — 282C 338 (32.6) (37.9) — — 2.0C 3.6 1.9C 3.4 — — 0.8762 No. 3 0.5B A distillate oil for(100) (20) 

general purpose 

heating for use in 

burners not 

requiring No. 1 

fuel oil 

(540) (640) (30 min) 

No. 4 55 -6C 0.50 — 0.10 — — — (45) (125) — — 5.8 26.4F 5.5 24.0F — — — — — 

Preheating not(130) 

usually required 

for handling 

or burning 

(20) 

No. 5 (Light) 55 — 1.00 — 0.10 — — — (>125) (300) — — >26.4 65F >24.0 58F — — — — — 

Preheating may(130) 

be required 

depending on 

climate and 

equipment 

No. 5 (Heavy) 55 — 1.00 — 0.10 — — — (>300) (900) (23) (40) >65 194F >58 168F (42) (81) — — — 

Preheating may(130) 

be required 

for burning and, 

in cold climates, 

may be required 

for handling 

No. 6 60 G 2.00 E — — — — — (>900) (9000) (>45) (300) — — — — >92 638 F — — — 

Preheating (140) 

required for 

burning and 

handling 

A It is the intent of these classifications that failure to meet any requirement of a given grade does not automatically place an oil in the next lower 

grade unless in fact it meets all requirements of the lower grade. 

B In countries outside the United States other sulfur limits may apply. 

C Lower or higher pour points may be specified whenever required by conditions of storage or use. When pour point less than -18°C (0°F) is 

specified, the minimum viscosity for grade No. 2 shall be 1.7 cSt (31.5 SUS) and the minimum 90% point shall be waived. 

D Viscosity values in parentheses are for information only and not necessarily limiting. 

E The amount of water by distillation plus the sediment by extraction shall not exceed 2.00%. The amount of sediment by extraction shall not 

exceed 0.50%. A deduction in quanity shall be made for all water and sediment in excess of 1.0%. 

F Where low sulfur fuel oil is required, fuel oil failing in the viscosity range of a lower numbered grade down to and including No. 4 may be supplied 

by agreement between purchaser and supplier. The viscosity range of the initial shipment shall be identified and advance notice shall be 

required when changing from one viscosity range to another. This notice shall be in sufficient time to permit the user to make the necessary 

adjustments. 

G Where low sulfur fuel oil is required. Grade 6 fuel oil will be classified as low pour + 15°C (60°F) max or high pour (no max). Low pour fuel oil 

should be used unless all tanks and lines are heated. 

© COPYRIGHT ASTM • REPRINTED WITH PERMISSION 

25

TYPICAL PROPERTIES OF COMMERCIAL FUEL OILS IN THE U.S. 

Grade of Carbon Residue, 

Fuel Oil Flash Point, °F Pour Point, °F Water, Vol. % Wt. % Ash, Wt. % 

1 106 to 174 -85 to -10 0.050 max. 0.200 max. – 

2 120 to 250 -60 to +35 0.060 max. 0.820 max. – 

4* 150 to 276 -40 to +80 0.3 max. 0.19 to 7.6 0.07 max. 

5 (Light)* 154 to 250 -15 to +55 0.08 to 0.6 2.10 to 13.6 0.001 to 0.08 

5 (Heavy)* 136 to 300+ -17 to +90 0.4 max. 1.55 to 9.6 0.001 to 0.16 

6 140 to 250 0 to +110 0.300 max. 1.02 to 15.80 0.001 to 0.630 

Grade of Viscosity, Specific Gravity Gross Heating 

Fuel Oil SSU @ 100°F 60/60°F Gravity, °API Sulfur, Wt % Value, Btu/gallon 

1 37 max. 0.79 to 0.85 47.9 to 34.8 0 to 0.47 131,100 to 138,700 

2 42 max. 0.80 to 0.92 45.3 to 21.9 0.04 to 0.5 132,600 to 147,400 

4* 35 to 160 0.85 to 0.99 34.6 to 12.1 0.18 to 1.81 140,400 to 151,700 

5 (Light)* 80 to 700 0.89 to 1.01 28.2 to 8.5 0.58 to 3.48 142,700 to 156,400 

5 (Heavy)* 240 to 1300 0.91 to 1.02 23.4 to 7.5 0.6 to 2.54 144,800 to 153,600 

6 240 to 6100 0.92 to 1.09 22.0 to -1.5 0.17 to 3.52 146,700 to 162,000 

The above data are summarized from Heating Oils, 1984, published by the American Petroleum Institute and U.S. 

Dept. of Energy. The ranges in the tables represent the extreme maximums and minimums for the oil samples 

included in the survey. 

*1975-1976 data. No data available for these grades in 1983-1984. 

Kinematic Viscosity, SSU @ 100°F, SSF @ 122°F, SR1 @ 140°F, or °E 

FUEL OIL VISCOSITY CONVERSIONS 

This chart converts four commonly-used fuel oil viscosity 

scales to a common base of centistokes 

ABBREVIATIONS: SSU = Saybolt Seconds Universal 

SSF = Saybolt Seconds Furol 

SRI = Seconds Redwood #1 

°E = Degrees Engler 

10,000 

8 

6 

4 

3 

2 

1000 

8 

6 

4 

3 

2 

100 

8 

6 

4 

3 

2 

10 

8 

6 

4 

3 

2 

1 

1 2 3 4 6 8 10 2 3 4 6 8 100 2 3 4 6 8 1000 2 3 

Kinematic Viscosity, Centistokes (CS) 

26 

SSU @ 100°F 

SR1 @ 140°F 

SSF @ 122°F 

°E

Specific Gravity @ 60°F 

1.1 

1.0 

0.9 

0.8 

To determine specific gravity of an oil, find °API at the bottom 

of the graph, read up to the curve, and left to the specific 

gravity. 

To find gross heating value of an oil, find °API at the bottom 

of the graph, read up to the curve, and right to the heating 

value. 

These charts show oil pressure drop per 100 equivalent 

feet of horizontal schedule 40 steel pipe. To determine total 

equivalent length, add equivalent lengths of fittings and 

valves (Page 16) to the actual linear feet of pipe. 

The charts for 1000 SSU and 10,000 SSU oils are 

accompanied by correction factors for oils of other viscosities. 

To find the pressure drop for an oil not on either of 

these charts, simply multiply the drop from the chart by the 

appropriate correction factor. 

If the entrance and exit ends of the oil line are at different 

elevations, the static head of the oil must be added to or 

subtracted from the calculated piping drop. 

Static head, psi = 0.433 x specific gravity of oil x elevation 

difference, ft. 

° API VS. OIL SPECIFIC GRAVITY 

& GROSS HEATING VALUE 

0.7 

0 10 20 30 40 50 60 

OIL PIPING PRESSURE LOSSES 

27 

° API 

For greater accuracy or for gravities not on this chart, use 

these equations: 

Specific gravity @ 60/60°F = 141.5 

°API + 131.5 

Gross Heating Value, Btu/lb 

= 17,887 + (57.5 x °API) - (102.2 x %S) 

where %S is weight % sulfur in the oil. 

Gross Heating Value, Btu/gal 

= g.h.v., Btu/lb x 8.335 x specific gravity 

Pressure Drop, psi per 

100 feet of equivalent 

pipe length 

10 

5 

1/2" 3/4" 

35 SSU Distillate Oil 

-160 

-155 

-150 

-145 

-140 

-135 

- 130 

1-1/4" 

Gr0ss Heating Value, Btu/Gallon x 1000 

0 

0 5 10 

Oil Flow, gpm 

15 20 

1"

Pressure Drop, psi per 100 feet 

of equivalent pipe length 

Pressure Drop, psi per 100 feet 

of equivalent pipe length 

20 

15 

10 

5 

OIL PIPING PRESSURE LOSSES (Cont’d) 

Pressure Drop, psi per 

100 feet of equivalent 

pipe length 

10 

5 

100 SSU Intermediate Oil 

1/2" 3/4" 1" 

0 

0 5 10 

Oil Flow, gpm 

15 20 

0 

0 5 10 

Oil Flow, gpm 

15 20 

20 

15 

10 

5 

1000 SSU Heavy Oil 

1" 1-1/4" 

10,000 SSU Heavy Oil 

2" 2-1/2" 

1-1/2" 

2" 

2-1/2" 

0 

0 5 10 

Oil Flow, gpm 

15 20 

28 

3" 

4" 

1-1/4" 

1-1/2" 

Pressure Drop 

Correction Factors 

for Other Viscosities 

Viscosity, Correction 

SSU Factor 

200 0.2 

300 0.3 

400 0.4 

500 0.5 

600 0.6 

700 0.7 

800 0.8 

900 0.9 

1200 1.2 

1500 1.5 

2000 2.0 

2500 2.5 

Pressure Drop 

Correction Factors 

for Other Viscosities 

Viscosity, Correction 

SSU Factor 

2000 0.2 

3000 0.3 

4000 0.4 

5000 0.5 

6000 0.6 

7000 0.7 

8000 0.8 

9000 0.9 

12000 1.2 

15000 1.5

OIL PIPING TEMPERATURE LOSSES 

This table lists the temperature drop of 220°F oil flowing through steel pipe insulated with 1" thick 85% magnesia pipe 

insulation. Ambient temperature is assumed to be 60°F. For oil temperatures other than 220°F, multiply the temperature loss by 

the appropriate correction factor. 

OIL TEMPERATURE DROP IN °F PER FOOT OF PIPE 

Oil Flow Nominal Pipe Size 

GPH 1/4 3/8 1/2 3/4 1 1-1/4 1-1/2 2 2-1/2 3 

.5 10.92 12.18 13.68 15.48 17.64 20.6 22.50 26.30 30.00 34.8 

1 5.46 6.09 6.84 7.74 8.82 10.3 11.25 13.15 15.00 17.4 

2 2.73 3.04 3.42 3.87 4.41 5.15 5.63 6.57 7.50 8.70 

3 1.82 2.03 2.28 2.58 2.94 3.43 3.75 4.38 5.00 5.75 

4 1.365 1.52 1.71 1.933 2.205 2.58 2.82 3.28 3.75 4.35 

5 1.09 1.218 1.368 1.548 1.764 2.06 2.25 2.63 3.00 3.48 

10 .546 .609 .684 .774 .882 1.03 1.125 1.315 1.50 1.74 

15 .364 .405 .455 .515 .588 .686 .750 .876 1.00 1.16 

20 .273 .304 .342 .387 .441 .515 .563 .657 .750 .870 

30 .182 .203 .228 .258 .294 .343 .375 .438 .500 .575 

40 .136 .152 .171 .193 .220 .258 .282 .328 .375 .435 

60 .091 .101 .114 .129 .147 .172 .187 .219 .250 .290 

80 .068 .076 .086 .097 .110 .129 .141 .164 .188 .218 

100 .055 .061 .068 .077 .088 .103 .113 .132 .150 .174 

200 .027 .030 .034 .039 .044 .052 .056 .066 .075 .087 

300 .018 .020 .023 .026 .029 .034 .038 .044 .050 .058 

OIL TEMPERATURE 

CORRECTION FACTORS 

Oil Oil 

Temperature, °F Factor Temperature, °F Factor 

130 0.44 190 0.81 

140 0.5 200 0.88 

150 0.56 210 0.94 

160 0.63 230 1.06 

170 0.69 240 1.13 

180 0.75 250 1.19 

Temperature losses from uninsulated pipe will vary with the 

pipe size. For 1/4" pipe, the losses are about 8 times the figures in 

the table. For 3" pipe, they are about 6 times the table values. 

29

CHAPTER 5 – STEAM & WATER 

BOILER TERMINOLOGY AND CONVERSION FACTORS 

Boiler horsepower – One boiler horsepower 

= 33,479 Btu/hr heat to steam 

= 34.5 lb/hr of water evaporated 

from and at 212°F 

= 9.8 Kilowatts 

Dry Steam – Steam which contains no liquid water. 

Enthalpy – Heat content, Btu/lb, of a liquid or vapor. 

Latent heat of vaporization – The heat required to convert a 

material from its liquid to its vapor phase without raising its 

temperature. The latent heat of vaporization of water at 1 

atmosphere pressure and 212°F is 970.3 Btu/lb. 

30 

Quality – In a mixture of steam and water, the weight percentage 

which is present as steam; in other words, the percent 

of complete vaporization which has taken place. The quality of 

saturated steam is 100%. 

Saturated Steam – Steam which is at the same temperature as 

the water from which it was evaporated. 

Wet Steam – Steam which contains liquid water. Its quality is 

less than 100%. 

PROPERTIES OF SATURATED STEAM 

V g, 

Specific h f, h fg, h g, 

Volume of Heat Content Latent Heat, Heat Content 

Temperature, Pressure, psi Vapor of Liquid, of Vaporization, of Vapor 

°F Absolute Gauge cu ft/lb Btu/lb Btu/lb Btu/lb 

32 .089 – 3304.7 -0.018 1075.5 1075.5 

40 .121 – 2445.8 8.03 1071.0 1079.0 

50 .178 – 1704.8 18.05 1065.3 1083.4 

60 .256 – 1207.6 28.06 1059.7 1087.7 

70 .363 – 868.4 38.05 1054.0 1092.1 

80 .507 – 633.3 48.04 1048.4 1096.4 

90 .698 – 468.1 58.02 1042.7 1100.8 

100 .949 – 350.4 68.00 1037.1 1105.1 

110 1.28 – 265.4 77.98 1031.4 1109.3 

120 1.69 – 203.3 87.97 1025.6 1113.6 

130 2.22 – 157.3 97.96 1019.8 1117.8 

140 2.89 _ 123.0 107.95 1014.0 1122.0 

150 3.72 – 97.07 117.95 1008.2 1126.1 

160 4.74 – 77.29 127.96 1002.2 1130.2 

170 5.99 – 62.06 137.97 996.2 1134.2 

180 7.51 – 50.22 148.00 990.2 1138.2 

190 9.34 – 40.96 158.04 984.1 1142.1 

200 11.53 – 33.64 168.09 977.9 1146.0 

212 14.696 0 26.80 180.17 970.3 1150.5 

220 17.19 2.49 23.15 188.23 965.2 1153.4 

240 24.97 10.27 16.32 208.45 952.1 1160.6 

260 35.43 20.73 11.76 228.76 938.6 1167.4 

280 49.20 34.50 8.64 294.17 924.6 1173.8 

300 67.01 52.31 6.47 269.7 910.0 1179.7 

320 89.64 74.94 4.91 290.4 894.8 1185.2 

340 117.99 103.29 3.79 311.3 878.8 1190.1 

360 153.01 138.31 2.96 332.3 862.1 1194.4 

380 195.73 181.03 2.34 353.6 844.5 1198.0 

400 247.26 232.56 1.86 375.1 825.9 1201.0 

500 680.86 666.16 0.67 487.9 714.3 1202.2 

600 1543.2 1528.5 0.27 617.1 550.6 1167.7 

700 3094.3 3079.6 0.075 822.4 172.7 995.2 

705.47* 3208.2 3193.5 0.051 906.0 0 906.0 

*Critical Temperature

1000's of Btu/hr Burner 

Input Required to Generate 

One Boiler Horsepower 

BTU/HR REQUIRED TO GENERATE ONE BOILER H.P. 

50 

45 

40 

35 

70 75 80 

% Boiler Efficiency 

85 90 

Pressuer Drop, psi per 100 ft of pipe 

10 

8 

6 

4 

3 

2 

1 

.8 

.6 

.4 

.3 

.2 

.1 

.08 

.06 

.04 

.03 

.02 

SIZING WATER PIPING 

1/2" 3/4" 1" 1-1/4"1-1/2" 2" 2-1/2" 3" 4" 

.01 

1 2 3 4 6 8 10 20 30 40 60 80 100 200 300 500 1000 

Water Flow, Gallons Per Minute 

Pressure drops are for 60°F water flowing in horizontal Schedule 40 steel pipe. 

31 

6" 

8"

SIZING STEAM PIPING 

Pipe Size, Lb/hr steam for piping pressure drop of 1 psi/100ft Lb/hr steam for piping drop of 5 psi/100 ft 

Inches Steam Pressure, psig Steam Pressure, psig 

(Schedule 40) 5 10 25 50 100 150 10 25 50 100 150 

3/4 31 34 43 53 70 84 73 93 120 155 185 

1 61 68 86 110 140 170 145 185 235 315 375 

1-1/4 135 150 190 235 310 370 320 410 520 690 820 

1-1/2 210 230 290 370 485 570 500 640 810 1,050 1,300 

2 425 470 590 750 980 1,150 1,000 1,300 1,650 2,150 2,600 

2-1/2 700 780 980 1,250 1,600 1,900 1,650 2,150 2,700 3,600 4,250 

3 1,280 1,450 1,800 2,250 2,950 3,500 3,050 3,900 4,300 6,600 7,800 

4 2,700 3,000 3,800 4,750 6,200 7,400 6,500 8,200 10,500 14,000 16,500 

6 8,200 9,200 11,500 14,500 19,000 22,500 19,500 25,000 31,500 42,000 50,000 

8 17,000 19,000 24,000 30,000 39,500 47,000 41,000 52,000 66,000 88,000 105,000 

These flows were calculated from Babcock’s Equation, 

Pd D5 where W = steam flow, lb/minute 

P = pressure drop, psi 

W = 87 (1 + 3.6 ) L D = inside diameter of pipe, inches 

D d = density of steam, lb/cu ft 

L = length of pipe run, feet 

32

CHAPTER 6 – ELECRICAL DATA 

ELECTRICAL FORMULAS 

Ohm’s Law Motor Formulas D.C. Circuit Power Formulas 

Amperes = Volts/Ohms Torque (lb-ft) = 5250 x Horsepower Watts = Volts x Amperes 

Ohms = Volts/Amperes rpm Amperes = Watts/Volts 

Volts = Amperes x Ohms Synchronous rpm = Hertz x 120 Volts = Watts/Amperes 

Poles Horsepower = Volts x Amperes x Efficiency* 

746 

A.C. Circuit Power Formulas 

Single-Phase Three-Phase 

Watts = Volts x Amps x Power Factor* = 1.73 x Volts x Amps x Power Factor* 

Amperes = WattsVolts x Power Factor* = Watts/1.73 x Volts x Power Factor* 

= kVA x 1000/Volts = kVA x 1000/1.73 x Volts 

= Horsepower x 746 = Horsepower x 746 

Volts x Efficiency* x Power Factor* 1.73 x Volts x Effic.* x Power Factor* 

Kilowatts = Amps x Volts x Power Factor* = 1.73 x Amps x Volts x Power Factor* 

1000 1000 

kVA = Amps x Volts = 1.73 x Amps x Volts 

1000 1000 

Horsepower = Volts x Amps x Effic.* x Pwr. Factor* = 1.73 x Volts x Amps x Effic.* x Pwr. Fact.* 

746 746 

*Expressed as a decimal 

ELECTRICAL WIRE – 

DIMENSIONS & RATINGS 

All data for solid copper wire 

A.W.G. Resistance, Maximum Allowable 

Wire Diameter, Ohms per 1000 Ft Current Capacity per 

Gauge Inches @ 77˚F NFPA 70-1984*, Amps 

0 .3249 .100 125-170 

1 .2893 .126 110-150 

2 .2576 .159 95-130 

3 .2294 .201 85-110 

4 .2043 .253 70-95 

6 .1620 .403 55-75 

8 .1285 .641 40-55 

10 .1019 1.02 30-40 

12 .0808 1.62 20-30 

14 .0641 2.58 15-25 

16 .0508 4.09 18 

18 .0403 6.51 14 

*Maximum current capacity permitted by National Electrical Code, 

NFPA 70-1984, varies with type of insulation, ambient temperature, 

voltage carried, and other factors. Consult NFPA 70-1984 for 

specific information. 

33 

NEMA SIZE STARTERS FOR MOTORS 

Starter size for 

460/3/60 

Horsepower 115/1/60 230/1/60 230/3/60 380/3/60 575/3/60 

Up to 1/3 00 00 00 00 00 

1/2 to 1 0 00 00 00 00 

1-1/2 1 1 00 00 00 

2 1 1 0 0 00 

3 2 2 0 0 0 

5 3 2 1 0 0 

7-1/2 3 2 1 1 1 

10 – 3 2 1 1 

15 – – 2 2 2 

20-25 – – 3 2 2 

30 – – 3 3 3 

40-50 – – 4 3 3 

60-75 – – 5 4 4 

100 – – 5 5 4 

125-150 – – 6 5 5 

200 – – 6 6 5 

All sizes listed apply only to magnetic starters with fusible 

alloy overload relays.

NEMA ENCLOSURES 

NEMA 1. General Purpose – Indoor 

Sheet metal enclosures intended for indoor use. Primary purpose 

is to prevent accidental personnel contact with enclosed 

equipment, although they will also provide some protection 

against falling dirt. 

NEMA 2. Drip Proof – Indoor 

Indoor enclosure that protects contents against falling noncorrosive 

liquids and dirt. Must be equipped with a drain. 

NEMA 3. Dust Tight, Raintight & Sleet-Resistant (Ice- 

Resistant), 

NEMA 3R. Rainproof & Sleet-Resistant (Ice-Resistant). 

NEMA 3S. Dust Tight, Raintight & Sleet-Proof (Ice-Proof) 

Outdoor enclosures for protection against windblown dust, rain 

and sleet. All have provision for locking. 

NEMA 4. Water Tight & Dust Tight – Indoor & Outdoor 

Protect contents against splashing, seeping, falling, or hosedirected 

water and severe external condensation. Commonly used 

in food-processing plants where equipment hosedown is required. 

NEMA 6. Submersible, Watertight, Dust Tight and Sleet (Ice)- 

Resistant–Indoor & Outdoor 

Capable of being submerged up to 30 minutes in up to 6 feet of 

water without harm to the contents. 

NEMA 7. Hazardous Locations – Indoor – Air Break 

Equipment 

Enclosures for use in atmospheres containing explosive gases 

and vapors as defined in Class 1, Division I, Groups A, B, C or D 

of the National Electrical Code. Enclosure must contain an internal 

explosion without causing an external hazard. Construction 

details vary with the nature of the explosive gas or vapor. 

NEMA 8. Hazardous Locations – Indoor – Oil-Immersed 

Equipment 

Enclosures for oil-immersed circuit breakers in Class I, 

Division I, Group A, B, C or D hazardous atmospheres. 

NEMA 9. Hazardous Locations – Indoor – Air-Break 

Equipment 

Used in Class II, Division I, Group E, F, or G hazardous locations 

as defined by the National Electrical Code. Enclosures are 

designed to exclude combustible or explosive dusts. 

NEMA 10. Mine Atmospheres 

For use in mines containing methane or natural gas. 

NEMA 11. Corrosion-Resistant and Drip Proof – Indoor 

Indoor enclosures that protect contents from dripping, seepage 

and external condensation of corrosive liquids, as well as corrosive 

fumes. 

NEMA 12. Industrial Use – Dust Tight & Drip Tight – Indoor 

Protect enclosed equipment from lint, fibers, flyings, dust, dirt 

and light splashing, seepage, dripping and external condensation 

of noncorrosive liquids. 

NEMA 13. Oil Tight & Dust Tight – Indoor 

Protect enclosed equipment from lint, dust and seepage, external 

condensation and spraying of water, oil, or coolant. They have 

oil-resistant gaskets and must have provision for oiltight conduit 

entry. 

For more complete details on application and construction specifications 

for NEMA Enclosures, refer to NEMA Standards 

Publication No. ICS 6. 

34 

ELECTRIC MOTORS– 

FULL LOAD CURRENT, AMPERES 

Single 

Three-Phase AC Motors 

Induction Type – 

Phase Squirrel Cage & 

Horse AC Motors Wound-Rotor 

Power 115V 230V 115V 230V 460V 575V 

1/6 4.4 2.2 — — — — 

1/4 5.8 2.9 — — — — 

1/3 7.2 3.6 — — — — 

1/2 9.8 4.9 4 2 1 .8 

3/4 13.8 6.9 5.6 2.8 1.4 1.1 

1 16 8 7.2 3.6 1.8 1.4 

1-1/2 20 10 10.4 5.2 2.6 2.1 

2 24 12 13.6 6.8 3.4 2.7 

3 34 17 — 9.6 4.8 3.9 

5 56 28 — 15.2 7.6 6.1 

7-1/2 80 40 — 22 11 9 

10 100 50 — 28 14 11 

15 — — — 42 21 17 

20 — — — 54 27 22 

25 — — — 68 34 27 

30 — — — 80 40 32 

40 — — — 104 52 41 

50 — — — 130 65 52 

60 — — — 154 77 62 

75 — — — 192 96 77 

100 — — — 248 124 99 

125 — — — 312 156 125 

150 — — — 360 180 144 

200 — — — 480 240 192

CHAPTER 7 – PROCESS HEATING 

HEAT BALANCES–DETERMINIING THE HEAT NEEDS OF 

FURNACES AND OVENS 

Although rules of thumb are frequently used to size furnace 

and oven burners, they have to be used with care. All 

rules of thumb are based on certain assumptions about production 

rates, furnace dimensions, and insulation. If the system 

under consideration differs from these assumed conditions, 

using a rule of thumb can result in a significant error. 

Gross 

Input 

(Purchased 

Fuel) 

Available 

Heat 

Flue Gas Loss 

Stored 

Heat 

The terms used in heat balance calculations, and their definitions, 

are: 

Gross heat input – the total amount of heat used by the furnace. 

It equals the amount of fuel burned multiplied by its 

heating value. 

Available heat – heat that is available to the furnace and its 

workload. It equals gross input minus flue gas losses. 

Flue gas losses – heat contained in flue gases as they are 

exhausted from the furnace. 

Stored heat – heat absorbed by the insulation and structural 

components of the furnace or oven to raise them to operating 

temperature. This stored heat becomes a loss each time the furnace 

is cooled down, because it has to be replaced on the next 

startup. Heat storage can usually be ignored on continuous furnaces, 

because cooldowns and restarts don't occur often. 

Wall losses – heat conducted out through the walls, roof and 

floor of the furnace due to the temperature difference between 

35 

For out-of-the ordinary conditions, or where more accurate 

results are required, heat balance calculations are preferred. A 

heat balance consists of calculating load heat requirements 

and adding losses to them to determine the heat input. 

Below is a schematic representation of the heat balance in 

a fuel-fired heat processing device. 

Wall 

Loss 

General heat balance in a fuel-fired heat processing device. 

Radiation 

Loss 

Conveyor 

Loss 

Net Output 

(Heat To Load) 

the inside and outside. At a constant temperature, wall losses 

will remain constant regardless of production rate. 

Radiation losses – heat lost from the furnace as radiant energy 

escaping through openings in walls, doors, etc. 

Conveyor losses – heat which is stored in conveying devices 

such as furnace cars and conveyor belts and which is lost 

when the heated conveyor is removed from the furnace. 

Net output – this is the heat that ultimately reaches the product 

in the oven or furnace. 

On page 36 is a simplified worksheet for carrying out a 

heat balance. By following this format, you can determine the 

gross heat input required at maximum load and minimum 

load conditions, along with the furnace turndown and theoretical 

thermal efficiency.

HEAT BALANCE TABLE 

Maximum Load Minimum Load 

Heat Balance Conditions Conditions 

Component (Full Production Rate) (Empty and Idling) 

Heat to load __________Btu/hr ____0____Btu/hr 

+ Wall losses + __________Btu/hr + _________Btu/hr 

+ Radiation losses + __________Btu/hr + _________Btu/hr 

+ Conveyor losses + __________Btu/hr + ____0____Btu/hr 

= Available heat = __________Btu/hr = _________Btu/hr 

required 

÷ Available heat, ÷ __________ ÷ _________ 

expessed as a 

decimal 

= Gross heat input = __________Btu/hr = _________Btu/hr 

Furnace turndown = Gross heat input, maximum load conditions = _________ 

Gross heat input, minimum load conditions 

Theoretical Thermal efficiency, % = 

Supporting Calculations: 

Heat to Load 

Heat to load = lb per hour x specific heat x temperature rise. 

Specific heats for many materials are listed on pages 37-39. 

For most common metals and alloys, use the graphs on page 40. 

Simply multiply lb/hr production rate by the heat content 

picked from the graph. 

Enter the heat to load under Maximum Load Conditions. 

Heat to load is usually zero under Minimum Load Conditions 

because no material is being processed through the oven or 

furnace. 

Wall Losses: 

Wall loss = Wall Area (inside) x heat loss, Btu/sq ft/hr. 

Typical heat loss data are tabulated on page 44 . 

If the roof and floor of the furnace are insulated with different 

materials than the walls, calculate their losses separately. 

Add all the losses together and enter them in both the 

Maximum Load and Minimum Load columns above. 

Caution: If the furnace is to be idled at a temperature lower 

than its normal operating temperature, wall losses will be correspondingly 

lower. Calculate them on the basis of the actual 

idling temperature. 

Radiation Losses: 

Radiation Losses = Opening Area x Black Body Radiation 

Rate x Shape Factor. See page 49 for radiation rates. Assume 

a Shape Factor of 1. 

Conveyor Losses: 

Treat the conveyor as you would a furnace load. 

Conveyor Loss = Lb/hr of conveyor heated x specific heat x 

(Temperature leaving furnace – temperature entering furnace) 

At minimum load, conveyor losses are usually zero because 

no material is being processed through the furnace. 

Available Heat: 

Available heat = Heat to load + wall losses + radiation losses 

+ conveyor losses. 

Calculate available heat for both maximum and minimum 

load conditions. 

Heat to load, maximum load conditions 

x 100 = _________ 

Gross heat input, maximum load conditions 

36 

Next, consult the available heat charts (page 51) to determine 

the percent available heat for the fuel, operating temperature, 

and fuel/air ratio conditions of this application. 

Enter this figure as a decimal on both sides above. 

Gross Input: 

Gross Input = Available heat (Btu/hr) ÷ Available heat 

(decimal). 

Figure this for both maximum and minimum load conditions. 

Gross input, maximum conditions, is the maximum heating 

input required of the combustion system you select. 

Furnace Turndown: 

Divide maximum load gross input by minimum load gross 

input. The result is the furnace or oven turndown. Your 

combustion system must provide at least this much turndown 

or the furnace will overshoot setpoint on idle. 

Theoretical Thermal Efficiency: 

% Efficiency = Heat to load, maximum load conditions x 100 

Gross heat input, maximum load conditions 

This is the maximum theoretical efficiency of the furnace, 

assuming it operates at 100% of rating with no production interruptions 

and with a properly adjusted combustion system. 

Heat Storage 

Heat Storage was left out of this analysis. Althought it is a 

factor in furnace efficiency, burner systems are rarely sized 

on the heat storage needs of the furnace. 

On continuous furnaces where cold startups occur infrequently, 

heat storage can usually be ignored without any 

major effect on efficiency calculations. On batch-type furnaces 

that cycle from hot to cold frequently, storage should be 

factored into efficiency calculations. 

Heat Storage = Inside refractory surface area, ft 2 x Heat 

Storage Capacity, Btu/ft 2 

Heat storage capacities for typical types of refractory construction 

are tabulated on Page 44.

THERMAL PROPERTIES OF VARIOUS MATERIALS 

Solid Latent Liquid Latent 

Density Specific Melting Heat of Specific Boiling Heat of 

Lb/Cu Ft Heat Point, Fusion, Heat, Point, Vaporization, 

Material @60°F Btu/Lb-°F °F Btu/Lb Btu/Lb-°F °F Btu/Lb 

Acetone – – -138 33.5 0.530 128-134 225.5 

Acetic Acid 65.8 0.540 62.6 44 0.462 244.4 152.8 

Air .0765 – – – 0.237 -311.0 91.7 

Alcohol-Ethyl 49.26 0.232 -173.2 44.8 0.648 172.4 369.0 

-Methyl 49.6 – -142.6 29.5 0.601 150.8 480.6 

Alumina 243.5 0.197 3722 – – – – 

Aluminum 166.7 0.248 1214 169.1 0.252 3272 – 

Ammonia 32° 45.6 0.502 -83.0 195 1.099 -37.3 543.2 

Andalusite 199.8 0.168 3290 – – – – 

Aniline 2.25 0.741 17.6 37.8 0.514 363 198 

Antimony 422 0.054 1166 70.0 0.054 2624 – 

Asbestos 124-174 0.195 – – – – – 

Asphalt-Trinidad 97 0.55 190 – 0.55 – – 

-Gilsonite 67.5 0.55 300 – 0.55 – – 

Arsenic 357.6 0.082 Sublimes – – – – 

Babbit 75 Pb 15 Sb 10 Sn – 0.039 462 26.2 0.038 – – 

84 Sn 8 Sb 8 Cu – 0.071 464 34.1 0.063 – – 

Bakelite – 0.30 – – – – – 

Beef Tallow 57-61 0.50 80-100 – – – – 

Beeswax 60 0.82 144 76.2 – – – 

Benzene-Benzol 55 0.299 41.8 55.6 0.423 176.3 169.4 

Beryllium 113.8 0.50 2345 621.9 0.425 5036 – 

Bismuth 615 0.033 518 18.5 0.035 2606 – 

Borax 105.5 0.238 1366 – – – – 

Brass 67 Cu 33 Zn 528 0.105 1688 71.0 0.123 – – 

85 Cu 15 Zn – 0.104 1877 84.4 0.116 – – 

90 Cu 10 Zn – 0.104 1952 86.6 0.115 – – 

Brick-Fireclay 137-150 0.240 – – – – – 

-Red 118 0.230 – – – – – 

-Silica 144-162 0.260 – – – – – 

Bronze 90 Cu 10 Al – 0.126 1922 98.6 0.125 – – 

90 Cu 10 Sn – 0.107 1850 84.2 0.106 – – 

80 Cu 10 Zn 10 Sn 534 0.095 1832 79.9 0.109 – – 

Cadmium 540 0.038 610 19.5 0.074 1412 409 

Calcium 96.6 0.170 1564 – – 2709 – 

Calcium Carbonate 175 0.210 Dec. 1517 – – – – 

Calcium Chloride 157 0.16 1422 97.7 – >2912 – 

Camphor 62.4 0.440 353 19.4 0.61 408 – 

Carbon, Amorphous 129 0.241 6300 – – 8721 – 

Carbon, Disulfide 79.2 – -166 – 0.24 115 150.8 

Carbon, Graphite 138.3 0.184 6300 – – 8721 – 

Castor Oil 59.6 – – – – – – 

Celotex – 0.40 – – – – – 

Celluloid – 0.36 – – – – – 

Cellulose 95 0.320 – – – – – 

Cement – 0.20 – – – – – 

Charcoal 18-38 0.165 – – – – – 

Chlorine 0.190 0.19 -151 41.3 – -30.3 121 

Chloroform 95.5 – -85 – 0.149 142.1 105.3 

Chromite 281 0.22 3956 – – – – 

Chromium 437 0.12 2822 57.1 – 4500 – 

Clay, Dry 112-162 0.224 3160 – – – – 

Coal (Anthracite) – 0.31 – – – – – 

Coal (Bituminous) – 0.30 – – – – – 

Coal Tar 76.7 0.413 196 – – 325 – 

Coal Tar Oil – – – – 0.34 390-910 136 

Cobalt 555 0.145 2723 – – 5252 – 

Coke – 0.2-0.38 – – – – – 

Concrete – 0.27 – – – – – 

Copper 558 0.104 1982 90.8 0.111 4703 – 

Cork – 0.48 – – – – – 

Corundum 250 0.304 3722 – – 6332 – 

Cotton – 0.32 – – – – – 

Cottonseed Oil 58 – 32 – 0.474 – – 

Cream – – – – 0.78 – – 

Cuprice Oxide 374-406 0.227 1944 – – – – 

T = Transformation Point Subl. = Sublimes Dec = Decomposes 

37

THERMAL PROPERTIES OF VARIOUS MATERIALS (Cont’d) 





Cyanite 225 0.227 3290 – – – – 

Diasporite 215 0.260 3722 – – – – 

Die Cast Metal: – – – – – – – 

87.3 Zn 8.1 Sn 4.1 Cu 0.5Al – 0.103 780 48.3 0.138 – – 

90 Sn 4.5 Cu 5.5 Sb – 0.070 450 30.3 0.062 – – 

80 Pb 10 Sn 10 Sb – 0.038 600 17.4 0.037 – – 

92 Al 8 Cu – 0.236 1150 163.1 0.241 – – 

Diphenyl 103 0.385 159 47 0.481 492 136.5 

Dolomite 181 0.222 – – – – – 

Dowtherm 58.8 0.53 180 – – 500 123 

Earth – 0.44 – – – – – 

Ebonite – 0.35 – – – – – 

Ether 45.9 – -180.4 – 0.529 94.3 159.1 

Fats – 0.46 – – – – – 

Fosterite 200 0.22 3470 – – – – 

Fuel Oil – – – – 0.45 – – 

Gasoline 42 – – – 0.514 176 128-146 

German Silver – 0.109 1850 86.2 0.123 – – 

Glass, Crown – 0.16 – – – – – 

Glass, Flint – 0.13 – – – – – 

Glass, Pyrex – 0.20 – – – – – 

Glass, Window (Soda Lime)160 0.19 2192 – – – – 

Glass Wool 1.5 0.16 – – – – – 

Glycerine 78.7 0.047 68 85.5 0.576 554 – 

Gold 1205 0.032 1945 28.5 0.034 5371 29 

Granite – – – – – – – 

Graphite 0.30-0.38 – Subl. 6606 – – – – 

Gypsum 145 0.259 2480 – – – – 

Hydrochloric Acid 75 – -12 – – – – 

Hydrogen .0053 – -434 27 – -423 194 

Hydrogen Sulfide – – -117 – – -79 – 

Iron 491 0.1162 2795 117 – 5430 – 

Iron, Gray Cast 443 0.119 2330 41.7 – – – 

Iron, White Cast 480 0.119 2000 59.5 – – – 

Kerosene – – – – 0.470 – 108 

Lead 711 0.032 621 9.9 0.032 3171 – 

Lead Oxide 575-593 0.049 1749 – – – – 

Leather – 0.36 – – – – – 

Lucite – 0.35 – – – – – 

Light Oil – – – – 0.5 600 145-150 

Linseed Oil 58 – -5 – 0.441 – – 

Lipowitz Metal – 0.041 140 17.2 0.041 – – 

Magnesite 187 0.200 Dec. 662 – – – – 

Magnesium 108.6 0.272 1204 83.7 0.266 – – 

Magnesium Oxide 223 0.23-0.30 5072 – – – – 

Manganese 500 0.171 2246 65.9 0.192 – – 

– – T = 1958 T = 43.5 – – – 

Marble – 0.21 – – – – – 

Mercury 885 0.033 -38 5.1 0.033 675 117 

Mica – 0.21 – – – – – 

Milk 63.4 – – – 0.847 – – 

Molasses 87.4 – – – 0.60 – – 

Molybdenum 636 0.065 4748 – – 8672 – 

Monel 550 0.129 2415 117.4 0.139 – – 

Mallite 188.8 – 3290 – 0.175 – – 

Naptha 41.2 – – – 0.493 306 184 

Napthalene 71.8 0.325 176 64.1 0.427 424.4 135.7 

Neats Foot Oil – – 32 – 0.457 – – 

Nickel 556 0.134 2646 131.4 0.124 – – 

Nichrome 517 – – – 0.111 – – 

Nitric Acid 96.1 – -43.6 – 0.445 186.8 207.2 

Nitrogen .0741 – -346 11.1 – -320 85.6 

Nylon – 0.55 – – – – _ 

T = Transformation Point Subl. = Sublimes Dec = Decomposes 

38

THERMAL PROPERTIES OF VARIOUS MATERIALS (Cont’d) 





Olive Oil 57.4 – 40 – 0.471 572 – 

Oxygen .0847 0.336 -361 5.98 0.394 -297 91.6 

Paraffin 54-57 0.622 126 63 0.712 750 

Petroleum 48-55 – – – 0.511 – – 

Phosphorus 114 0.189 111 9.05 – 536 234 

Pitch, Coal Tar 62-81 0.45 86-300 – – – – 

Plaster of Paris 0.265 1.14 – – – – – 

Platinum 1335 0.036 3224 49 0.032 7933 – 

Porcelain 150 0.26 – – – – – 

Potassium Nitrate 129.2 0.19 646 88 – Dec. 752 – 

Quartz 165.5 0.23 – – – – – 

Resin-Phenolic 80-100 0.3-0.4 – – – – – 

-Copals 68.6 0.39 300-680 – – – – 

Rhodium 773 0.058 3571 – – – – 

Rockwool 6 0.198 – – – – – 

Rose’s Metal – 0.043 230 18.3 0.041 – – 

Rosin 68 0.5 170-212 – – – – 

Rubber 62-125 0.48 248 – – – – 

Salt-Rock 135 0.22 1495 – – 2575 – 

Sand 162 0.20 – – – – – 

Sandstone – 0.22 – – – – 

Sawdust – 0.5 – – – – – 

Shellac 75 0.40 170-180 – – – – 

Silica 180 – 3182 – 0.1910 4046 – 

Silicon 155 0.176 2600 – – 4149 

Silicon Carbide 199 0.23 4082 – – Subl. 3032 – 

Sillimanite 202 0.175 3290 – – – – 

Silk 84 0.33 – – – – – 

Silver 656 0.063 1761 46.8 0.070 3634 – 

Snow – 0.5 32 – – – – 

Sodium Carbonate 151.5 0.306 1566 – – Dec. – 

Sodium Nitrate 140.5 0.231 597 116.8 – 1716 – 

Sodium Oxide 142 0.231 Subl. 2327 – – – – 

Sodium Sulfate 168 0.21 – – – – – 

Solder - 50 Pb 50 Sn 580 0.051 450 23 0.046 – – 

- 63 Pb 37 Sn – 0.044 468 14.8 0.041 

Steel - 0.3% C 491 0.129 (70-1330°)* *Phase change between 1330 & 1500° requires 

0.166 (1500-2500°) additional 80 Btu/lb. 

Stone 168 0.20 – – – – – 

Sugar - Cane 102 0.30 320 _ – – – 

Sulfur 119-130 0.19 235 16.9 0.234 840 652 

Sulfuric Acid 115.9 0.239 50.0 – 0.370 – – 

Talc – 0.21 – – – – 

Tar-Coal 71-81 0.35 – – – – – 

Tin 460 0.069 450 25.9 0.0545 4118 – 

Titanium 281 0.14 3272 – – – – 

Toluene 53.7 – – – 0.40 230.5 150.3 

Tungsten 1204 0.034 6098 – – 10652 – 

Turpentine 53.7 – – – 0.411 318.8 133.3 

Type Metal-Linotype – 0.036 486 21.5 0.036 – – 

Type Metal-Stereotype 670 0.036 500 26.2 0.036 – – 

Uranium 370 0.028 2071 – – – – 

Vanadium 372 0.115 3110 – – 5432 – 

Varnish – – – – – 600 – 

Water 62.37 0.480 32 144 1.00 212 970.4 

Wood 19-56 0.33 – – – – – 

Wood’s Metal – 0.041 158 17.2 0.042 – – 

Wool 81 0.325 – – – – 

Xylene 54.3 – -18 – 0.411 288 147 

Zinc 443 0.107 786 47.9 0.146 1706 – 

Zinc Oxide 341 0.125 >3272 – – – – 

Zircon 293 0.132 4622 – – – – 

Zirconia 349 0.103 4919 – – – – 

Zirconium 399 0.067 3100 – – 9122 – 

T = Transformation Point Subl. = Sublimes Dec. = Decomposes 

39

Heat Content, Btu/lb 

Heat Content, Btu/lb 

150 

100 

50 

0 

600 

500 

400 

300 

200 

100 

THERMAL CAPACITIES OF METALS & ALLOYS 

Solder 

50 Pb/50Sn 

40 

Babbit 

75 Pb/15Sb/10Sn 

Alloy 903 Die Cast Zinc 

Pure Zinc 

0 100 200 300 400 500 600 700 800 900 

Temperature, °F 

Pure Aluminum 

Aluminum Die Cast Alloy 380.0 

Pure Magnesium 

Magnesium Casting Alloy AZ91A 

Titanium Alloy 

Ti-6AI-4V 

85-15 Red Brass 

Lead 

0.3% Carbon 

Steel 

Pure 

Copper 

65-35 Yellow Brass 

0 

0 200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 2600 2800 

Temperature, °F

INDUSTRIAL HEATING OPERATIONS–TEMPERATURE & HEAT REQUIREMENTS 

Approximate Heat Content of 

Material Operation Temperature, °F Material, Btu/lb* 

Aluminum Age 190-470 30-100 

Anneal 645-775 130-190 

Homogenize 850-1150 175-300 

Hot Work (Extrude, 

Roll, Forge) 500-950 100-240 

Melt 1175-1500 370-550 

Solution Heat Treat 820-1025 170-280 

Stabilize 435-655 80-160 

Stress Relieve 650-775 130-190 

Asphalt Melt 350-450 160-220 

Babbit Melt 600-1000 60-75 

Brass Anneal 800-1450 70-150 


Roll, Forge) 1150-1650 100-150 

Melt 1930-2370 230-290 

Recrystallize 550-700 40-70 

Stress Relieve 475 30-40 

Bread Bake 300-500 – 

Bronze Anneal 800-1650 70-170 


Roll, Forge) 1200-1750 100-160 

Melt 1600-2350 220-320 


Brick, common Burn 1900-2000 800-950 

fireclay Burn 2100-2200 900-1050 

Cake Bake 300-350 – 

Candy Cook 225-300 – 

Cast Iron (Gray) Anneal 1300-1750 290-420 

Austenitize (Harden) 1450-1700 330-410 

Melt 2800-2900 720-750 

Normalize 1600-1700 380-410 


Temper (Draw) 300-1020 35-175 

Cast Iron, Ductile Anneal 1300-1650 290-390 

(Nodular Iron) Austenitize (Harden) 1550-1700 360-410 

Normalize 1600-1725 380-415 


Temper (Draw) 800-1300 120-290 

Cast Iron (Malleable) Anneal (Malleablize) 1650-1750 290-420 


Temper (Draw) 1100-1300 190-290 

Cement Calcine 2800-3000 – 

China Fire 1900-2650 450-600 

Glaze 1500-1900 350-450 

Coffee Roast 600-800 – 

Cookies Bake 375-450 – 

Copper Anneal 500-1200 50-120 


Roll, Forge) 1300-1750 130-180 

Melt 1970-2100 290-310 

Enamel 

(Paint) Bake 250-450 – 

(Porcelain) Fire 1700-1800 – 

*Heat contained in material only. Does not include furnace or oven losses or available 

heat correction. 

41

INDUSTRIAL HEATING OPERATIONS–TEMPERATURE & HEAT REQUIREMENTS 

(Cont’d) 

Approximate Heat Content of 

Material Operation Temperature, °F Material, Btu/lb* 

Frit Smelt 2000-2400 400-550 

Glass Melt 2200-2900 400-650 

Anneal 1000-1200 – 

Gold Melt 2000-2370 125-145 

Lacquer Dry 150-200 – 

Lead Melt 620-700 18-32 

Lime Calcine 2000-2200 – 

Magnesium Age 265-625 70-140 

Homogenize 200-800 30-190 


Roll, Forge) 550-850 110-200 

Melt 1150-1550 375-490 



Meat Smoke 100-150 – 

Pie Bake 500 – 

Potato Chips Fry 350-400 – 

Sand Dry 350-500 60-90 

Sand Cores Bake 400-450 70-80 

Silver Melt 1800-1900 155-165 

Solder Melt 400-500 40-45 

Steel Anneal 1150-1650 150-270 

(Carbon & Alloy) Austenitize 1320-1650 180-270 

Carbonitride 1300-1650 180-270 

Carburize 1600-1800 260-300 

Cyanide 1400-1600 210-260 

Hot Work (Forge, 

Roll) 2200-2400 360-400 

Nitride 925-1050 110-140 

Normalize 1500-1700 240-280 


Steel (Stainless) Anneal 1150-2050 150-340 


Hot Work (Forge, 

Roll) 1600-2350 260-390 


Temper (Draw) 300-1200 25-160 

Tin Melt 500-650 70-80 

Titanium Age 900-1000 120-140 

Anneal 1100-1600 150-250 

Hot Work (Roll, 

Forge) 1300-1900 180-310 



Varnish Cook 500-750 – 

Zinc Galvanize 850-900 130-140 

Melt 800-900 130-150 

Hot Work (Extrusion, 

Rolling) 200-575 10-55 

*Heat contained in material only. Does not include furnace or oven losses or available 

heat correction. 

42

B 

A 

CRUCIBLES FOR METAL MELTING – DIMENSIONS & CAPACITIES 

C 

D 

Dimensions, inches Approximate Capacity, lb 

A, B, C, 

Size Top Bilge Bottom D, Red 

Number OD OD OD Height Aluminum Brass Copper Magnesium 

20 7 11 ⁄16 8 3 ⁄8 6 1 ⁄8 10 15 ⁄16 20 65 67 13 

25 8 3 ⁄16 8 7 ⁄8 6 1 ⁄2 10 15 ⁄16 25 81 84 16 

30 8 5 ⁄8 9 5 ⁄16 6 13 ⁄16 11 1 ⁄2 30 97 100 20 

35 9 9 3 ⁄4 7 1 ⁄8 12 35 113 117 23 

40 9 3 ⁄8 10 1 ⁄8 7 7 ⁄16 12 1 ⁄2 40 129 134 26 

45 9 7 ⁄8 10 11 ⁄16 7 13 ⁄16 13 3 ⁄16 45 146 151 29 

50 10 1 ⁄4 11 1 ⁄8 8 1 ⁄8 13 3 ⁄4 50 162 167 33 

60 10 13 ⁄16 11 11 ⁄16 8 9 ⁄16 14 7 ⁄16 60 194 201 39 

70 11 1 ⁄4 12 3 ⁄16 8 15 ⁄16 15 1 ⁄16 70 226 234 46 

80 11 11 ⁄16 12 11 ⁄16 9 1 ⁄4 15 5 ⁄8 80 259 268 52 

90 12 1 ⁄8 13 1 ⁄8 9 9 ⁄16 16 3 ⁄16 90 291 301 59 

100 12 1 ⁄2 13 1 ⁄2 9 7 ⁄8 16 11 ⁄16 100 323 335 65 

125 13 14 1 ⁄16 10 5 ⁄16 17 3 ⁄8 125 404 418 81 

150 13 3 ⁄4 14 7 ⁄8 10 7 ⁄8 18 3 ⁄8 150 485 502 98 

175 14 3 ⁄8 15 9 ⁄16 11 3 ⁄8 19 1 ⁄4 175 566 586 114 

200 15 16 1 ⁄4 11 7 ⁄8 20 200 657 669 130 

225 15 1 ⁄2 16 13 ⁄16 12 5 ⁄16 20 3 ⁄4 225 728 753 147 

250 16 17 5 ⁄16 12 11 ⁄16 21 3 ⁄8 250 808 837 163 

275 16 7 ⁄16 17 13 ⁄16 13 22 275 889 921 179 

300 16 7 ⁄8 18 1 ⁄4 13 3 ⁄8 22 1 ⁄2 300 970 1004 195 

400 18 3 ⁄16 19 11 ⁄16 14 7 ⁄16 24 5 ⁄16 400 1293 1339 261 

RADIANT TUBES – SIZING & INPUT DATA 

TUBE EXTERNAL SURFACE AREA DATA 

Straight Tube 

Tube Sq. In. 180° Short Radius Elbow 180° Long Radius Elbow 

OD, Per Foot 

Inches of Length CL to CL, in. sq. in. CL to CL, in. sq. in. 

3 113 6 89 9 133 

31 ⁄4 123 6 96 9 144 

31 ⁄2 132 6 104 9 155 

33 ⁄4 141 6 111 9 167 

4 151 8 158 12 237 

41 ⁄4 160 8 168 12 252 

41 ⁄2 170 8 178 12 267 

43 ⁄4 179 8 188 12 281 

5 188 10 247 15 370 

51 ⁄4 198 10 259 15 389 

51 ⁄2 207 10 271 15 407 

53 ⁄4 217 10 284 15 426 

6 226 12 355 18 533 

61 ⁄4 236 12 370 18 555 

61 ⁄2 245 12 385 18 577 

63 ⁄4 254 12 400 18 600 

8 302 16 632 24 947 

81 ⁄4 311 16 651 24 977 

81 ⁄2 320 16 671 24 1007 

Maximum Heat Transfer 

Rate, Btu/hr per sq. in. of 

External Tube Surface 

43 

70 

60 

50 

40 

30 

Maximum Heat Transfer Rates 

For Good Service Life of Alloy Tubes 

Tube enclosed 

on 3 sides 

Tube free to radiate on 3 sides 

1500 1600 1700 1800 1900 

Furnace Temperature, °F

HEAT LOSSES, HEAT STORAGE & COLD FACE 

TEMPERATURES – REFRACTORY WALLS 

HL Hot Face Temperature, °F 

Wall HS 

Construction TC 1000 1200 1400 1600 1800 2000 2200 2400 

HL 550 705 862 1030 1200 1375 1570 1768 

9" Hard Firebrick HS 12,500 15,400 18,400 21,500 24,700 27,950 31,200 34,500 

TC 282 320 355 387 418 447 477 505 

9" Hard Firebrick + HL 130 168 228 251 296 341 390 447 

4 1 ⁄2" 2300° Insulating F.B. HS 22,380 27,700 33,060 38,450 43,930 49,350 55,800 61,920 

TC 147 162 188 195 211 227 242 260 

9" Hard Firebrick + HL 111 128 155 185 209 244 282 325 

4 1 ⁄2" 2000° Insulating F.B. + HS 23,750 29,650 35,640 41,940 48,420 54,890 61,410 68,120 

2" Block Insulation TC 138 144 156 169 179 193 205 218 

HL 185 237 300 365 440 521 – – 

4 1 ⁄2" 2000° Insulating F.B. HS 1180 1450 1750 2075 2400 2720 – – 

TC 170 190 211 230 253 274 – – 

HL 95 124 159 189 225 266 – – 

9" 2000° Insulating F.B. HS 2260 2840 3420 4000 4620 5240 – – 

TC 132 146 160 172 187 200 – – 

HL 142 178 218 264 312 362 416 474 

9" 2800° Insulating F.B. HS 3170 3970 4790 5630 6480 7360 8230 9160 

TC 151 166 183 200 217 234 250 267 

9" 2800° Insulating F.B. + HL 115 140 167 197 232 272 307 347 


TC 142 149 161 164 183 202 215 228 



2" Block Insulation TC 119 127 136 147 156 168 177 187 


3" Block Insulation HS 7730 9765 11,760 13,810 15,880 17,973 20,084 22,209 

TC 139 150 163 175 188 200 212 224 

HL 575 730 897 1075 1300 1525 1775 2030 

4 1 ⁄2" Dense Castable HS 5270 9520 11,310 13,060 14,820 16,120 18,300 20,030 

TC 282 319 356 393 430 467 504 541 

HL 315 410 500 627 694 844 947 1134 

9" Dense Castable HS 13,120 16,240 19,960 23,673 26,355 29,212 32,019 35,861 

TC 218 248 280 305 321 352 377 406 

HL 390 490 610 730 860 1000 1155 1332 

9" Plastic HS 17,825 21,735 25,640 29,610 33,345 37,125 41,040 44,415 

TC 232 261 290 319 348 378 407 436 

8" Ceramic Fiber – HL 27 45 64 86 114 146 178 216 

Stacked Strips, 8 #/cu ft HS 850 1018 1190 1358 1528 1692 1823 2039 

Density TC 95 105 115 126 138 152 165 180 



Density TC 92 101 110 119 129 140 151 163 



Density TC 91 97 104 112 121 130 140 151 

9" Hard Firebrick + 3" HL 177 240 309 383 463 642 721 800 

Ceramic Fiber Veneer, HS 1920 3680 5430 7178 9219 11,200 12,503 14,891 

8 #/cu ft Density TC 170 191 214 235 259 305 320 341 


3" Ceramic Fiber Veneer, HS 1150 2012 2910 3795 4576 5402 6272 7450 


9" Dense Castable + HL 170 221 273 329 381 487 559 635 

3" Ceramic Fiber Veneer, HS 1910 3603 5340 7083 8899 10,576 12,136 14,149 


HL = Heat Loss, Btu/hr – sq ft HS = Heat Storage, Btu/sq ft TC = Cold Face Temperature, °F 

Note:These values are typical for the materials listed and are sufficiently accurate for estimating 

purposes. Values for specific brands of refractories may differ. 

44

Btu/Hr Required Per SCFM of Process Stream 

Btu/Hr Required Per SCFM of Process Stream 

2000 

1500 

1000 

500 

3500 

3000 

2500 

2000 

1500 

1000 

AIR HEATING & FUME INCINERATION 

HEAT REQUIREMENTS USING “RAW GAS” BURNERS 

T2 = 1500°F Stream Outlet Temperature 

1300°F 

1200°F 

1100°F 

1000°F 

900°F 

700°F 

600°F 

800°F 

1400°F 

0 

0 200 400 600 800 1000 

500 

T1 

T 1 , Process Stream Inlet Temperature, °F 

700°F 

600°F 

0 

0 200 400 600 800 1000 

T1 

T2 = 1500°F Stream Outlet Temperature 

900°F 

800°F 

1100°F 

1000°F 

1300°F 

1200°F 

1400°F 

T 1 , Process Stream Inlet Temperature, °F 

T2 

T2 

45 

These curves show the heat input required per 

scfm of process air stream where the burner derives 

its combustion air from the stream. They can also be 

used to calculate heat requirements for direct-fired 

fume incinerators, provided: 

1. Oxygen content of the fume stream is at least 20%, 

and 

2. Combustible solvents in the fume stream make a 

negligible contribution to the heat input. 

The curves are calculated from the relationship. 

Btu/hr = scfm x 1.1 x (T 2-T 1) 

available heat, expressed as a decimal 

For high stream inlet and outlet temperatures, they 

produce more accurate results than the traditional relationship 

Btu/hr = scfm x 1.1 x (T 2-T 1), 

which does not take variations of available heat into 

account. 

If the application requires a burner with a separate 

combustion air source, use the curves below. 

AIR HEATING & FUME INCINERATION 

HEAT REQUIREMENTS USING BURNERS WITH SEPARATE 

COMBUSTION AIR SOURCES 

These curves show the heat input required per scfm 

of process air stream using a burner with a separate 

combustion air source. They are calculated from the 

relationship: 

Btu/hr = scfm x 1.1 x (T 2-T 1) 

available heat, expressed as a decimal 

See above for heat requirements of systems using a 

“raw gas” burner.

FUME INCERATION – SELECTION & SIZING GUIDELINES 

I. Process Information Required 

A. Fume stream flow rate, scfm or acfm. (If acfm, 

specify temperature at which flow is measured.) 

Maximum and minimum flow rates are required. 

B. Fume stream temperature at inlet to burner at 

maximum and minimum flow rates. 

C. Oxygen content of fume stream. 

D. Amount of particulates or other non-volatile 

matter in fume stream. 

E. Incineration temperature required, typically: 

600-900°F for catalytic incinerators 

1200-1500°F for thermal incinerators. 

F. Residence time required in combustion chamber, 

typically, 0.3 to 0.7 seconds. 

II. Burner Type Selection 

Two basic types of burners are used to fire fume incinerators: 

raw gas burners, which obtain their combustion 

air from the incoming fume stream, and fresh air burners, 

which obtain theirs from an external source. 

Raw gas burners permit higher fuel efficiency, but they 

can’t be used under as wide a variety of operating conditions. 

The table below provides some general guidelines 

for burner selection. 

Fresh Air 

Selection Factor Raw Gas Burner Burner 

Oxygen content of 18-21% ok ok 

fume stream 13-18% maybe–check mfr. ok 

below 13% no ok 

Fume stream Up to 1100°F Depends on burner– ok 

temperature check mfr. 

entering burner Over 1100°F no ok 

Particulates or None 

other non-vola- Low 

tiles in stream Heavy 

ok 

probably ok 

Depends on burner– 

ok 

ok 

ok 

check mfr. 

III. Calculating Burner Input 

A. For raw gas burners, use the chart on the top of page 

45. 

B. For fresh air burners use the chart on the bottom of 

page 45. 

These charts give Btu/hr required per scfm of 

fume stream. Multiply this figure by the fume 

stream flow rate, in scfm, to determine total burner 

heat input. 

C. If the burner will take part of its combustion air 

from the fume stream and the rest from an outside 

source, heat input can be closely estimated with 

this method: 

From page 45, deteremine Btu/hr required with 

a raw gas burner. Call this Br. 

From page 45, deteremine Btu/hr required with 

a 100% fresh air burner. Call this Bf. 

Btu/hr (partial fresh air) = 

Br + % fresh combustion air IV. Sizing Profile Plates 

If the burner is the type that is placed inside the 

fume duct, it has to be surrounded with a profile plate. 

Fumes are forced to pass through the gap between the 

profile plate and burner, ensuring that they mix completely 

with the burner flame. 

To size the profile gap, you need to know: 

1.Temperature of the fume stream passing over the 

burner, 

2.Fume stream pressure drop required across the profile 

gap (see burner manufacturer’s catalog data). 

Refer to the chart on page 17. Locate the required 

pressure drop at the bottom of the chart, then read up 

to the appropriate temperature curve and left to the 

stream velocity. Divide this velocity into the fume 

stream flow expressed in acfm: 

Profile gap, sq ft = Fume stream flow, acfm 

Fume stream velocity, ft/min 

For best results, the profile gap must be uniform 

width around the perimeter of the burner. Check manufacturer’s 

literature for specific recommendations on 

design and location of profile plates. 

{ 

{ 

V. 

NOTE: The air diffuser openings in some types of 

burners are considered part of the profile area. If so, 

deduct the area of these openings from the total profile 

area. The result will be the area of the gap around 

the burner. 

Sizing Downstream Combustion Chamber 

A. Chamber Cross-sectional area (A), Good practice 

requires no great than 30 ft/sec velocity in the com- 

{ 

bustion chamber, so 

A, sq ft = acfm of heated fume stream 

1800 

B. Combustion chamber length (L) is dictated by 

(Bf–Br) 

100 

the required residence time. 

L, feet = Stream velocity x residence time. 

If, for example, velocity is 30 ft/sec, and residence 

time is 0.5 seconds, L is 15 feet. 

WARNING! Incineration of fume streams containing 

compounds of chlorine, fluorine, or sulfur will produce 

combustion products which may be toxic or corrosive, or 

both. Consult with environmental authorities before considering 

fume incineration. 

46

LIQUID HEATING – BURNER SIZING GUIDELINES 

I. Tank Heating 

To determine the immersion burner size for heating a 

liquid tank, conduct two heat balances–one for heatup 

requirements, the other for steady-state operating 

requirements. Use the larger of the two Btu inputs 

obtained from these calculations. 

A. Heat Balance – Heatup Requirements 

1.Heat to water 

Btu/hr = Lb water x temperature rise, °F 

heatup time required, hr 

or 

Btu/hr = 8.3 x gallons water x temperature rise, °F 


or 

Btu/hr = 62.4 x cu ft water x temperature rise, °F 


Common practice allows the following heatup 

times for various size tanks: 

Tank Capacity Heatup 

Gallons Cu Ft Time, hr 

0-375 0-50 2 

375-750 50-100 4 

750-1500 100-200 6 

Over 1500 Over 200 8 

2.Surface losses – evaporation & radiation 

Btu/hr = Exposed bath surface x heat loss 

from Table 1. 

3.Tank wall losses 

Btu/hr = Total sq ft of tank walls & bottom x wall 

loss from Table 1. 

4.Tank heat storage 

Btu/hr = 

Total sq ft, tank walls & bottom x storage, Table 1. 


5.Total heatup requirements 

Heat to water 

+ Surface losses 

+ Tank wall losses 

+ Tank heat storage 

= Total heatup requirement 

47 

B. Heat Balance – Steady State Heat Requirements 

1.Heat to workload 

Btu/hr = 

Lb of work processed x 

hr 

specific heat x temperature rise, °F 

(Work weight must include all baskets & fixtures) 

Specific heat of steel is 0.14 Btu/lb - °F. 

See pages 37 to 39 for other materials. 

2.Surface losses – evaporation & radiation 

Same as Step A.2. 

3.Tank wall losses 

Same as Step A.3. 

4.Heat to makeup water 

Btu/hr = 

makeup rate, gal/hr x 8.3 x temperature rise, °F 

5.Total steady state heat requirement 

Heat to workload 

+ Surface losses 

+ Tank wall losses 

+ Heat to makeup water 

= Total steady state requirement 

C. Compare the heat requirements calculated in 

Steps A.5 and B.5. Select the larger of the two . 

(This is the net hourly input to the tank.) 

D. Gross Heat Input (Burner Firing Rate) 

Gross Input, Btu/hr = Net Input from A.5 or B.5 x 100 

% Efficiency required 

Efficiency is a function of immersion tube 

length and burner firing rate. 70% is a commonly 

used efficiency rating. 

E. Immersion Tube Sizing 

See burner manufacturer’s product literature 

for tube sizing recommendations. 

Table 1. Tank losses & storage 

Surface Losses, Wall Losses, Btu/sq ft-hr Heat Storage, 

Liquid Btu/sq ft-hr Btu/sq ft 

Temperature, Evapor- Radia- Insulation Thickness Steel Thickness 

°F ation* tion Total* None 1" 2" 3" 1/8" 1/4" 

90 80 50 130 50 12 6 4 21 42 

100 160 70 230 70 15 8 6 28 56 

110 240 90 330 90 19 10 7 35 70 

120 360 110 470 110 23 12 9 42 84 

130 480 135 615 135 27 14 10 49 98 

140 660 160 820 160 31 16 12 56 112 

150 860 180 1040 180 34 18 13 63 126 

160 1100 210 1310 210 38 21 15 70 140 

170 1380 235 1615 235 42 23 16 77 154 

180 1740 260 2000 260 46 25 17 84 168 

190 2160 290 2450 290 50 27 19 91 182 

200 2680 320 3000 320 53 29 20 98 196 

210 3240 360 3590 360 57 31 22 105 210 

220 4000 420 4420 380 62 33 23 112 224 

250 — 510 — 510 70 40 25 133 266 

275 — 600 — 600 81 45 29 151 301 

300 — 705 — 705 92 51 33 168 336 

325 — 850 — 850 103 57 36 186 371 

350 — 990 — 990 114 63 40 203 406 

400 — 1335 — 1335 138 75 49 238 476 

*Water or water-based solutions only.

II. Spray Washers 

Three methods are presented for calculating spray 

washer heat requirements. The first is the most accurate, 

making use of detailed heat loss factors. The 

other two are rule-of-thumb methods. While not as 

accurate as method A, they are useful for quickly 

estimating burner inputs. 

A. Heat Loss Method 

1.Data required: 

Gpm capacity of spray nozzles 

Height & width of washer housing (hood) 

Height & width of opening through which 

work passes 

Liquid pressure head 

Liquid temperature 

Location of stage in washer 

2.Heat Loss factors 

From Table 2, find the heat loss factors for 

housing height opening width 

housing width liquid pressure 

opening height liquid temperature 

Add all these factors together to get the combined 

factor, f. 

3.Stage location multiplier, M 

Location Multiplier 

Entrance Stage 1.75 

Intermediate Stage 1.00 

After a Cold Rinse 1.25 

Exist Stage 1.50 

4.Calculation of Gross Burner Input 

Btu/hr = Gpm x 500 x f x M 

This method yields gross burner input because 

an immersion tube efficiency of 70% has 

already been assumed in the heat loss factors. 

Table 2. Spray Washer Heat Loss Factors 

Housing Opening Liquid 

Wide High Wide High Press. Temp. 

Ft. f Ft. f Ft. f Ft. f PSIG f °F f 

2 .7 1 .8 140 .4 

3 .8 1 .3 2 .9 1 .5 5 .4 145 .5 

4 .9 2 .4 3 1.0 2 .6 7.5 .5 150 .6 

5 1.0 3 .5 4 1.1 3 .7 10 .6 155 .7 

6 1.1 4 .6 5 1.2 4 .8 12.5 .7 160 .8 

7 1.2 5 .7 6 1.3 5 .9 15 .8 165 .9 

8 1.3 6 .8 7 1.4 6 1.0 17.5 .9 170 1.0 

9 1.4 7 .9 8 1.5 7 1.1 20 1.0 175 1.3 

10 1.5 8 1.0 9 1.6 8 1.3 22.5 1.2 180 1.6 

11 1.6 9 1.1 10 1.7 9 1.5 30 1.4 185 1.9 

12 1.7 10 1.2 11 1.8 10 1.7 32.5 1.6 190 2.2 

13 1.8 11 1.3 12 1.9 11 1.9 35 1.8 

14 1.9 12 1.4 13 2.0 12 2.1 37.5 2.0 

15 2.0 13 1.5 14 2.1 13 2.3 40 2.2 

16 2.1 14 1.6 15 2.2 14 2.5 50 2.6 

17 2.2 100 3.5 

48 

B. Temperature Drop Rule of Thumb 

1.Data required: 

Gpm capacity of spray nozzles 

Temperature of liquid 

Tube efficiency (usually 70%) 

2.Approximate temperature drop of water. Table 

3 lists the approximate loss in water temperature 

as it is sprayed onto the workload. 

Table 3. Water Temperature Drop 

Water Temperature 

Temperature, °F Drop, °F 

150 5 

160 6 

170 7 

180 8 

190 9 

200 10 

3.Calculation of gross burner input. 

Btu/hr = Gpm x 500 x Temp Drop x 100 

% Efficiency 

4.Tank sizing 

Tank capacity = 3 x Gpm spray capacity 

C. Quick Method Rule of Thumb 

Btu/hr gross burner input = 

4000 x Gpm sprayed @ 30 psi x 100 

% Efficiency 

Capacities of spray nozzles are listed in Table 4. 

Table 4. Capacities of Spray Nozzles 

PSI Ft. Hd. 

Gallons per minute of water through 

a nozzle diameter of: 

Press (Approx.) 1/4" 5/16" 3/8" 7/16" 1/2" 5/8" 3/4" 

5 11.5 3.3 5.2 7.4 10.2 13.3 20.8 30.0 

10 23.0 4.7 7.3 10.4 14.3 18.7 29.3 42.3 

15 35.0 5.8 9.1 12.9 17.7 23.2 36.2 52.3 

20 46.5 6.7 10.5 14.8 20.7 26.7 41.8 60.5 

25 57.5 7.4 11.7 16.6 22.7 29.7 46.8 67.0 

30 68.5 8.1 12.9 18.2 24.8 32.4 50.7 73.0 

35 81.0 8.8 13.8 19.7 27.0 35.2 55.1 79.5 

40 92.5 9.4 14.8 21.3 28.8 37.7 58.9 85.0 

45 104.0 10.0 15.7 22.4 30.6 39.9 65.1 90.0 

50 115.0 10.5 16.5 23.5 32.1 42.0 65.7 94.6 

55 126.5 11.0 17.3 24.7 33.7 44.1 68.9 99.5 

60 138.0 11.0 18.1 25.8 35.2 46.1 72.1 104.0 

65 150.0 12.0 18.8 26.9 36.7 48.0 75.0 108.2 

70 162.0 12.4 19.6 27.9 38.1 49.7 77.9 112.0 

75 172.0 12.9 20.2 28.9 39.4 51.5 80.6 116.0 

80 184.5 13.3 20.9 29.9 40.7 53.3 83.1 119.9 

85 195.0 13.7 21.5 30.7 41.8 54.7 85.5 123.5 

90 205.0 14.0 22.0 31.4 42.9 56.2 87.7 126.7 

95 214.5 14.4 22.6 32.1 43.9 57.5 89.8 129.5 

100 224.0 14.6 23.1 32.8 44.8 58.7 91.7 132.0 

Above values are based on an orifice discharge coefficient of .80 

ORIFICE FLOW EQUATION: 

Q = 19.65 C D 2 H 

WHERE: 

Q = Gallons per minute 

D = Diameter of orifice in inches 

H = Pressure drop across orifice in feet head 

C = Orifice discharge coefficient

Heat Transfer Rate, Btu/Sq Ft x 1000 

350 

300 

250 

200 

150 

100 

50 

BLACK BODY RADIATION 

1000°F 60°F 

1500°F 

0 

500 1000 1500 2000 2500 3000 3500 

Source (Hotter) Temperature, °F 

49 

Receiver (Colder) Temperature 

1800°F 

2000°F 

2200°F 

These curves are plotted from the relationship 

Q = AK (T1 4-T 4) 2 (page 8.2) 

1 

+ 

1 - 1 

P 1 

P 2 

where P 1 & P 2 equal 1, that is, the heat source and receiver both 

have emissivities of 1.0, and they are arranged so there is no barrier 

to heat transfer between them. 

2400°F 

2600°F 

THERMOCOUPLE DATA 

ANSI Calibration Code B E J K R S T 

Useful Temp. Range, °F 1600-3100 32-1600 400-1400 700-2300 1800-2700 1800-2700 -300 + 700 

Positive Element Pt-30%Rh* Chromel** Iron Chromel** Pt-13%Rh* Pt-10%Rh* Copper 

Negative Element 

Color Coding 

Pt-6%Rh* Constantan Constantan Alumel** Pt* Pt* Constantan 

Positive Element Gray Purple White Yellow Black Black Blue 

Negative Element Red Red Red Red Red Red Red 

Outer Insulation on Purple or Black or Yellow or Blue or 

Duplex Wire Gray Brown/Purple Brown/Black Brown/Yellow Green Green Brown/Blue 

Plugs & Jacks 

*Pt = Platinum, Rh = Rhodium 

**Trademarks - Hoskins Mfg. Co. 

Gray Purple Black Yellow Green Green Blue 

How to Deteremine Thermocouple Polarity if Wire Identification is Missing: 

Types B, R, and S: Gently flex the ends of both wires. The stiffer wire is the positive element. 

Type K: Negative element is slightly magnetic. 

Type J: Positive element is magnetic. 

Type T: Positive element has characteristic pinkish-orange color of copper. 

2800°F 

3000°F 

3200°F

ORTON STANDARD PYROMETRIC CONES 

TEMPERATURE EQUIVALENTS 

Cone Type Self- Self- Cone Type 

Heating Rate Large Regular Large Iron Free Supporting Regular Supporting Iron Free Small Regular Small PCE Heating Rate 

Cone number 108°F/hr 270°F/hr 108°F/hr 270°F/hr 108°F/hr 270°F/hr 108°F/hr 270°F/hr 540°F/hr 270°F/hr Cone number 

022 1074 1092 1087 1094 1157 022 

021 1105 1132 1112 1143 1195 021 

020 1148 1173 1159 1180 1227 020 

019 1240 1265 1243 1267 1314 019 

018 1306 1337 1314 1341 1391 018 

017 1348 1386 1353 1391 1445 017 

016 1407 1443 1411 1445 1517* 016 

015 1449 1485 1452 1488 1549* 015 

014 1485 1528 1488 1531 1616 014 

013 1539 1578 1542 1582 1638 013 

012 1571 1587 1575 1591 1652 012 

011 1603 1623 1607 1627 1684 011 

010 1629* 1641* 1623 1656 1632 1645 1627 1659 1686* 010 

09 1679* 1693* 1683 1720 1683 1697 1686 1724 1751* 09 

08 1733* 1751* 1733 1773 1737 1755 1735 1774 1801* 08 

07 1783* 1803* 1778 1816 1787 1807 1780 1818 1846* 07 

06 1816* 1830* 1816 1843 1819 1834 1816 1845 1873* 06 

05 1/2 1852 1873 1852 1886 1855 1877 1854 1888 1908 05 1/2 

05 1888* 1915* 1890 1929 1891 1918 1899 1931 1944* 05 

04 1922* 1940* 1940 1967 1926 1944 1942 1969 2008* 04 

03 1987* 2014* 1989 2007 1990 2017 1990 2010 2068* 03 

02 2014* 2048* 2016 2050 2017 2052 2021 2052 2098* 02 

01 2043* 2079* 2052 2088 2046 2082 2053 2089 2152* 01 

1 2077* 2109* 2079 2111 2080 2113 2082 2115 2154* 1 

2 2088* 2124* Not Manufactured 2091 2127 Not Manufactured 2154* 2 

3 2106* 2134* 2104 2136 2109 2138 2109 2140 2185* 3 

4 2134* 2167* 2142 2169 2208* 4 

5 2151* 2185* 2165 2199 2230* 5 

6 2194* 2232* 2199 2232 2291* 6 

7 2219* 2264* 2228 2273 2307* 7 

8 2257* 2305* 2273 2314 2372* 8 

9 2300* 2336* 2300 2336 2403* 9 

10 2345* 2381* 2345 2381 2426* 10 

11 2361* 2399* 2361 2399 2437* 11 

12 2383* 2419* 2383 2419 2471* 2439* 12 

13 2410* 2455* 2428 2458 2460 2460* 13 

13 1/2 Not Manufactured 2466 2493 Not Manufactured 13 1/2 

14 2530* 2491* 2489 2523 2548 2548* 14 


15 2595* 2608* 2583 2602 2606 2606* 15 


16 2651* 2683* 2655 2687 2716 2716* 16 

17 2691* 2705* 2694 2709 2754 2754* 17 

18 2732* 2743* 2736 2746 2772 2772* 18 

19 2768* 2782* 2772 2786 2806 2806* 19 

20 2808* 2820* 2811 2824 2847 2847* 20 

21 2847* 2856* 2851 2860 2883* 21 

23 2887* 2894* 2890 2898 2921* 23 

26 2892* 2921* 2950* 26 

27 2937* 2961* 2984* 27 

28 2937* 2971* 2995* 28 

29 2955* 2993* 3018* 29 

30 2977* 3009* 3029* 30 

31 3022* 3054* 3061* 31 

31 1/2 ND ND 3090* 31 1/2 

32 3103* 3123* 3123* 32 

32 1/2 3124* 3146* 3135* 32 1/2 

33 3150* 3166* 3169* 33 

34 3195* 3198* 3205* 34 

35 3243* 3243* 3245* 35 

36 3268* 3265* 3279* 36 

37 ND ND 3308 37 

38 ND ND 3362 38 

39 ND ND 3389 39 

40 ND ND 3425 40 

41 ND ND 3578 41 

42 ND ND 3659 42 

The temperature equivalent tables are designed to be a guide for the selection of cones to use during firing. The temperature listed may only have a relative value to 

the user. However, the values do provide a good starting point and once the proper cones are determined for a particular firing condition, excellent firing control can 

be maintained. NOTES: ND = Not determined *Temperature equivalents as determined by the National Bureau of Standards by H.P. Beerman (See Journal of the 

American Ceramic Society Volume 39, 1956) Large cones at 2 inch mounting height, Small & PCE cones at 15/16 inch. 

1. The temperature equivalents in this table apply only to Orton Standard Pyrometric Cones, heated at the rate indicated in air atmosphere. 

2. The rates of heating shown at the head of each column of temperature equivalents were maintained during the last several hundred degrees of temperature rise. 

3. The temperature equivalents are not necessarily those at which cones will deform under firing conditions different from those under which the calibration determination 

were made. 

4. For reproducible results, care should be taken to insure that the cones are set in a plaque with the bending face at the correct angle of 8° from the vertical with the 

cone tips at a uniform height above the plaque. 

©1986 The Edward Orton Jr. Ceramic Foundation. Reprinted with permission. 

50

CHAPTER 8 – COMBUSTION DATA 

AVAILABLE HEAT CHARTS 

Available heat for Birmingham Natural Gas (1002 Btu/cu ft, 0.60 sp gr) vs. % Excess Air and Combustion Air Temperature 

(at 10% excess air). 

% Available Heat (Higher Heating Value) 

90 

80 

70 

60 

50 

40 

30 

20 

10 

250% XS AIR 

300% XS AIR 

350% XS AIR 

60°F 

10% Excess Air (preheated) 

200% XS AIR 

150% XS AIR 

0 

1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000 2100 2200 2300 2400 2500 

Flue Gas Exit Temperature °F 

AVAILABLE HEAT FOR VARIOUS FUEL GASES 

These curves assume 0% excess air. The excess air curves above for Birmingham Natural Gas can be used for butane, 

propane, natural, mixed, coke oven, & carbureted water gas without more than 5% error in the available heat. 

BUTANE 3200 BTU 

PROPANE 2500 BTU 

NATURAL GAS 1232 BTU 



MIXED GAS 800 BTU 

COKE OVEN GAS 600 BTU 

CARBURETED WATER GAS 534 BTU 

COKE OVEN GAS 490 BTU 

BLUE WATER GAS 310 BTU 

PRODUCER GAS 157 BTU 

PRODUCER GAS 116 BTU 

Copyright 1983, GTE Products Corp., Towanda, PA 18848 USA 

Used by Permission 

100% XS AIR 

51 

50% XS AIR 

1400°F 

1200°F 

1000°F 

800°F 

400°F 

0% XS AIR 

25% XS AIR 

200 600 1000 1400 1800 2200 2600 3000 3400 3800 0 

Flue Gas Temperature °F 

10% XS AIR 

2400 

2200 

2000 

1800 

1600 

1400 

1200 

1000 

800 

600 

400 

200 

Available Heat Btu/Cu. Ft.

% Flue Gas Constituent 

16 

14 

12 

10 

8 

6 

4 

2 

% CO 2 - #6 OIL 

FLUE GAS ANALYSIS CHART 

% CO 2 - #2 OIL 

% CO 2 - PROPANE 

% O 2 - DRY SAMPLE 

52 

% O 2 - SATURATED SAMPLE 

% CO 2 - NATURAL GAS 

0 

0 20 40 60 80 100 120 140 160 180 200 

Oxygen curves are plotted for 1002 Btu/cu ft Birmingham 

natural gas. These curves can be used for all common fuel 

gases and fuel oils with no more than 0.2% error in oxygen 

content. 

Use the “O 2 – dry sample” curve with flue gas analyzers 

that use dryers or condensers to remove water from the flue 

THEORETICAL FLAME TIP 

TEMPERATURE VS. EXCESS AIR 

The maximum theoretical temperature of combustion gases 

at the tip of a flame decreases with increasing amounts of 

excess air. The curve bleow shows this relationship for natural 

gas completely burned in 60°F combustion air, but is reaonsably 

accurate for most other common hydrocarbon fuels. 

Maximum Theoretical Temperature 

of Products of Combustion (°F) 

3200 

3000 

2500 

2000 

1500 

1000 

500 

% Excess Air 

0 

0 200 400 600 800 1000 1200 1400 1600 1800 

% Excess Air in Flue Gas 

gas sample. For analyzers which add water to produce a saturated 

sample, use the “O 2 – saturated sample” curve. 

% CO 2 curves are based on typical propane and fuel oil 

anlyses. If the fuel composition differs, actual CO 2 curves 

may vary slightly from those shown. 

HEAT TRANSFER RELATIONSHIPS 

Conduction 

Q = kA (t1-t2) L 

Convection 

Q = fA (t1-t2) Radiation 

Q = AK (T1 4-T 4) 2 

1 + 1 - 1 

P1 P2 Q =heat transferred, Btu/hr 

A =surface area across which heat is 

being transferred, sq. ft. 

t 1 =temperature of heat source, °F 

t 2 =temperature of heat receiver, °F 

L =thickness of object through which heat 

is conducted 

k =conductivity of material, Btu-ft 

hr-sq ft-°F 

f =convection film coefficient, Btu-ft 

hr-sq ft-°F 

K =Stefan-Boltzmann constant, 

=.1724 x 10 -8 Btu/sq ft-hr-(°R) 4 

P 1 =emissivity of heat source 

P 2 =emissivity of heat receiver 

T 1 =temperature of heat source, °R 

T 2 =temperature of heat receiver, °R 

(°R = °F + 460)

Furnacr Thermal Head or Draft, "wc 

Due to Gas Buoyancy 

.20 

.15 

.10 

.05 

THERMAL HEAD & COLD AIR INFILTRATION INTO FURNACES 

Furnace 

Height Above 

Hearth 

16' 

14' 

12' 

10' 

8' 

6' 

4' 

0 

0 500 1000 1500 2000 100 200 300 400 500 

Furnace 

Temperature °F 

Flue Cross-Sectional Area, Sq. In. 

Per 1000 SCFH of Flue Gases 

30 

20 

10 

8 

6 

5 

4 

3 

2 

Air Infiltration 

SCFH/ Sq. In. 

1 

1 2 3 4 5 6 8 10 20 30 40 50 

These curves predict the flue area required per 1000 scfh of 

flue gases, based on the average temperature of those gases 

and the height of the furnace stack. Flue openings are assumed 

to be simple orifices with a discharge coefficient of 0.6, and 

all pressure drop across those orifices is provided by the thermal 

head of the flue gases. 

This method is conservative – it will produce generously 

sized flues. 

FURNACE FLUE SIZING 

Stack Height, Ft, Above Furnace Hearth 

53 

The natural buoyancy of heated gases causes them to rise 

and collect under the roof of a furnace or oven. This creates 

a natural pressure differential, called thermal head or draft, 

which tends to pull cold air in through furnace leaks on topflued 

furnaces. These leaks are most pronounced at low fire, 

when burner combustion gas flow is insufficient to replace 

furnace gases drawn out by thermal head. 

This graph can be used to predict thermal head and cold 

air infiltration. 

Example: Determine thermal head and cold air infiltration 

in a 10' tall furnace operating at 1600°F. 

Solution: Read up from 1600°F furnace temperature to the 

intersection of the 10' curve. Read to the left to find thermal 

head, 0.08" w.c. To determine air infiltration, read right to 

the infiltration curve and then down to the infiltration rate, 

280 scfh per square inch. 

2500°F 

1500°F 

500°F 

Average 

Flue Gas 

Temp. 

Refer to Page 23 for volumes of combustion products for 

various fuels. Remember that if the combustion system is to 

be operated with excess air, the volume of combustion products 

has to be adjusted accordingly. 

Average flue gas temperature will have to be estimated, 

taking into account the effect of stack heat losses and dilution 

air.

CHAPTER 9 – MECHANICAL DATA 

DIMENSIONAL AND CAPACITY DATA – SCHEDULE 40 PIPE 

Diameter, Inches Cross-Sectional Area Weight Per Foot, lb. 

Wall Sq. in. of of of 

Actual Actual Thickness, Pipe Water Pipe and 

Nominal Inside Outside Inches Outside Inside Metal Alone In Pipe Water 

1/8 0.269 0.405 0.068 0.129 0.057 0.072 0.25 0.028 0.278 

1/4 0.364 0.540 0.088 0.229 0.104 0.125 0.43 0.045 0.475 

3/8 0.493 0.675 0.091 0.358 0.191 0.167 0.57 0.083 0.653 

1/2 0.622 0.840 0.109 0.554 0.304 0.250 0.86 0.132 0.992 

3/4 0.824 1.050 0.113 0.866 0.533 0.333 1.14 0.232 1.372 

1 1.049 1.315 0.133 1.358 0.864 0.494 1.68 0.375 2.055 

1-1/4 1.380 1.660 0.140 2.164 1.495 0.669 2.28 0.649 2.929 

1-1/2 1.610 1.900 0.145 2.835 2.036 0.799 2.72 0.882 3.602 

2 2.067 2.375 0.154 4.431 3.356 1.075 3.66 1.454 5.114 

2-1/2 2.469 2.875 0.203 6.492 4.788 1.704 5.80 2.073 7.873 

3 3.068 3.500 0.216 9.621 7.393 2.228 7.58 3.201 10.781 

3-1/2 3.548 4.000 0.226 12.568 9.888 2.680 9.11 4.287 13.397 

4 4.026 4.500 0.237 15.903 12.730 3.173 10.80 5.516 16.316 

5 5.047 5.563 0.258 24.308 20.004 4.304 14.70 8.674 23.374 

6 6.065 6.625 0.280 34.474 28.890 5.584 19.00 12.52 31.52 

8 7.981 8.625 0.322 58.426 50.030 8.396 28.60 21.68 50.28 

10 10.020 10.750 0.365 90.79 78.85 11.90 40.50 34.16 74.66 

12 11.938 12.750 0.406 127.67 113.09 15.77 53.60 48.50 102.10 

14 13.126 14.000 0.437 153.94 135.33 18.61 63.30 58.64 121.94 

16 15.000 16.000 0.500 201.06 176.71 24.35 82.80 76.58 159.38 

18 16.876 18.000 0.562 254.47 223.68 30.79 105.00 96.93 201.93 

20 18.814 20.000 0.593 314.16 278.01 36.15 123.00 120.46 243.46 

Circumference, Sq. Ft. of Surface Contents of Pipe Lineal Feet To Contain 

Inches Per Lineal Foot Per Lineal Foot 

Nominal 1 LB. 

Dia. In. Outside Inside Outside Inside Cu. Ft. Gal. 1 Cu. Ft. 1 Gal. of Water 

1/8 1.27 0.84 0.106 0.070 0.0004 0.003 2533.775 338.74 35.714 

1/4 1.69 1.14 0.141 0.095 0.0007 0.005 1383.789 185.00 22.222 

3/8 2.12 1.55 0.177 0.129 0.0013 0.010 754.360 100.85 12.048 

1/2 2.65 1.95 0.221 0.167 0.0021 0.016 473.906 63.36 7.576 

3/4 3.29 2.58 0.275 0.215 0.0037 0.028 270.034 36.10 4.310 

1 4.13 3.29 0.344 0.274 0.0062 0.045 166.618 22.28 2.667 

1-1/4 5.21 4.33 0.435 0.361 0.0104 0.077 96.275 12.87 1.541 

1-1/2 5.96 5.06 0.497 0.422 0.0141 0.106 70.733 9.46 1.134 

2 7.46 6.49 0.622 0.540 0.0233 0.174 42.913 5.74 0.688 

2-1/2 9.03 7.75 0.753 0.654 0.0332 0.248 30.077 4.02 0.482 

3 10.96 9.63 0.916 0.803 0.0514 0.383 19.479 2.60 0.312 

3-1/2 12.56 11.14 1.047 0.928 0.0682 0.513 14.565 1.95 0.233 

4 14.13 12.64 1.178 1.052 0.0884 0.660 11.312 1.51 0.181 

5 17.47 15.84 1.456 1.319 0.1390 1.040 7.198 0.96 0.115 

6 20.81 19.05 1.734 1.585 0.2010 1.500 4.984 0.67 0.080 

8 27.09 26.07 2.258 2.090 0.3480 2.600 2.878 0.38 0.046 

10 33.77 31.47 2.814 2.622 0.5470 4.100 1.826 0.24 0.029 

12 40.05 37.70 3.370 3.140 0.7850 5.870 1.273 0.17 0.021 

14 47.12 44.76 3.930 3.722 1.0690 7.030 1.067 0.14 0.017 

16 53.41 51.52 4.440 4.310 1.3920 9.180 0.814 0.11 0.013 

18 56.55 53.00 4.712 4.420 1.5530 11.120 0.644 0.09 0.010 

20 62.83 59.09 5.236 4.920 1.9250 14.400 0.517 0.07 0.008 

54

B 

A 

A 

90° Elbow 

B 

DIMENSIONS OF MALLEABLE IRON THREADED FITTINGS 

per ANSI B 16.3-1977 

D 

E 

A 

C 

A C 

90° Street Elbow Street Tee 

(150 lb only) 

F G 

45° Elbow 45° Street Elbow 45° Y-Bend 

(150 lb only) 

A 

G 

CLASS 150 FITTINGS 

Thread 

Engage- 

M1 Close 

M2 Med. 

M3 Open 

Size ment A B C D E F G H J K Pattern Pattern Pattern 

1/8 0.25 0.69 – 1.00 – – – – 0.53 0.96 – – – – 

1/4 0.32 0.81 0.73 1.19 0.73 0.94 – – 0.63 1.06 1.00 – – – 

3/8 0.36 0.95 0.80 1.44 0.80 1.03 1.93 1.43 0.74 1.16 1.13 – – – 

1/2 0.43 1.12 0.88 1.63 0.88 1.15 2.32 1.71 0.87 1.34 1.25 1.00 1.25 1.50 

3/4 0.50 1.31 0.98 1.89 0.98 1.29 2.77 2.05 0.97 1.52 1.44 1.25 1.50 2.00 

1 0.58 1.50 1.12 2.14 1.12 1.47 3.28 2.43 1.16 1.67 1.69 1.50 1.87 2.50 

1-1/4 0.67 1.75 1.29 2.45 1.29 1.71 3.94 2.92 1.28 1.93 2.06 1.75 2.25 3.00 

1-1/2 0.70 1.94 1.43 2.69 1.43 1.88 4.38 3.28 1.33 2.15 2.31 2.19 2.50 3.50 

2 0.75 2.25 1.68 3.26 1.68 2.22 5.17 3.93 1.45 2.53 2.81 2.62 3.00 4.00 

2-1/2 0.92 2.70 1.95 3.86 1.95 2.57 6.25 4.73 1.70 2.88 3.25 – – 4.50 

3 0.98 3.08 2.17 4.51 2.17 3.00 7.26 5.55 1.80 3.18 3.69 – – 5.00 

3-1/2 1.03 3.42 2.39 – – – – – 1.90 – – – – – 

4 1.08 3.79 2.61 5.69 2.61 3.70 8.98 6.97 2.08 3.69 4.38 – – 6.00 

5 1.18 4.50 3.05 6.86 – – – – 2.32 – – – – – 

6 1.28 5.13 3.46 8.03 – – – – 2.55 – – – – – 

CLASS 300 FITTINGS 

Size 

Thread 

Engagement 

A B C D E H J K M1 M2 M3 1/4 0.43 0.94 0.81 1.44 – – 0.78 1.37 – – – – 

3/8 0.47 1.06 0.88 1.63 – – 0.83 1.62 1.44 – – – 

1/2 0.57 1.25 1.00 2.00 1.00 1.38 0.98 1.87 1.69 – – – 

3/4 0.64 1.44 1.13 2.19 1.13 1.56 1.08 2.12 1.75 – – – 

1 0.75 1.63 1.31 2.56 1.31 1.81 1.26 2.37 2.00 1.75 2.50 3.00 

1-1/4 0.84 1.94 1.50 2.88 1.50 2.13 1.38 2.87 2.38 2.25 2.50 3.00 

1-1/2 0.87 2.13 1.69 3.13 1.69 2.31 1.43 2.87 2.69 3.00 3.50 6.00 

2 1.00 2.50 2.00 3.69 2.00 2.69 1.68 3.62 3.19 4.00 6.00 8.00 

2-1/2 1.17 2.94 2.25 4.50 – – 2.06 4.12 3.69 – – – 

3 1.23 3.38 2.50 5.13 – – 2.17 4.12 4.06 – – – 

H 

55 

A 

A A 

Tee 

J K 

A 

A 

A A 

Cross 

M1 

M2 

M3 

Cap Coupling Reducer Return Bend

SHEET METAL GAUGES & WEIGHTS 

Carbon Steel Galvanized Steel Stainless (Cr-Ni) Steel 

Gauge Thickness, Thickness, Thickness, 

No. in. lb. per sq. ft. in. lb per sq. ft in. lb. per sq. ft. 

7 .1793 7.500 – – – – 

8 .1644 6.875 .1681 7.031 .165 6.930 

9 .1495 6.250 .1532 6.406 .1563 6.563 

10 .1345 5.625 .1382 5.781 .135 5.670 

11 .1196 5.000 .1233 5.156 .120 5.040 

12 .1096 4.375 .1084 4.531 .1054 4.427 

13 .0897 3.750 .0934 3.906 .090 3.780 

14 .0747 3.125 .0785 3.281 .0751 3.154 

15 .0673 2.812 .0710 2.969 .0703 2.953 

16 .0598 2.500 .0635 2.656 .0595 2.499 

17 .0538 2.250 .0575 2.406 .0563 2.363 

18 .0478 2.000 .0516 2.156 .048 2.016 

19 .0418 1.750 .0456 1.906 .042 1.764 

20 .0359 1.500 .0396 1.656 .0355 1.491 

21 .0329 1.375 .0366 1.531 .0344 1.444 

22 .0299 1.250 .0336 1.406 .0293 1.231 

23 .0269 1.125 .0306 1.281 .0281 1.181 

24 .0239 1.000 .0276 1.156 .0235 .987 

25 .0209 .875 .0247 1.031 .0219 .919 

26 .0179 .750 .0217 .906 .0178 .748 

27 .0164 .688 .0202 .844 .0172 .722 

28 .0149 .625 .0187 .781 .0151 .634 

29 .0135 .563 .0172 .719 – – 

30 .0120 .500 .0157 .656 – – 

SHEET WIRE GAUGES & WEIGHTS 

Diameter, inches Diameter, inches 

Steel Steel 

Gauge Wire Gauge Wire 

No. AWG 1 Gauge 2 BWG 3 No. AWG 1 Gauge 2 BWG 3 

0 .3249 .3065 .340 15 .0571 .0720 .072 

1 .2893 .2830 .300 16 .0508 .0625 .065 

2 .2576 .2625 .284 17 .0453 .0540 .058 

3 .2294 .2437 .259 18 .0403 .0475 .049 

4 .2043 .2253 .238 19 .0359 .0410 .042 

5 .1819 .2070 .220 20 .0320 .0348 .035 

6 .1620 .1920 .203 21 .0285 .0317 .032 

7 .1443 .1770 .180 22 .0253 .0286 .028 

8 .1285 .1620 .165 23 .0226 .0258 .025 

9 .1144 .1483 .148 24 .0201 .0230 .022 

10 .1019 .1350 .134 25 .0179 .0204 .020 

11 .0907 .1205 .120 26 .0159 .0181 .018 

12 .0808 .1055 .109 27 .0142 .0173 .016 

13 .0720 .0915 .095 28 .0126 .0162 .014 

14 .0641 .0800 .083 29 .0113 .0150 .013 

30 .0100 .0140 .012 

1 American Wire Gauge or Brown & Sharpe Gauge for 

non-ferrous wire, including electrical wire. 

2 Or Washburn & Moen Gauge. 

3 Birmingham Wire Gauge or Stubs Gauge. 

56

CIRCUMFERENCES AND AREAS OF CIRCLES 

In Inches 

Dia. Circum. Area Dia. Circum. Area Dia. Circum. Area 

1/64 .04909 .00019 3 9.4248 7.0686 8 25.133 50.265 

1/32 .09818 .00077 1/16 9.6211 7.3662 1/8 25.525 51.849 

3/64 .14726 .00173 1/8 9.8175 7.6699 1/4 25.918 53.456 

1/16 .19635 .00307 3/16 10.014 7.9798 3/8 26.311 55.088 

3/32 .29452 .00690 1/4 10.210 8.2958 1/2 26.704 56.745 

1/8 .39270 .01227 5/16 10.407 8.6179 5/8 27.096 58.426 

5/32 .49087 .01917 3/8 10.603 8.9462 3/4 27.489 60.132 

3/16 .58905 .02761 7/16 10.799 9.2806 7/8 27.882 61.862 

7/32 .68722 .03758 1/2 10.996 9.6211 9 28.274 63.617 

1/4 .78540 .04909 9/16 11.192 9.9678 1/8 28.667 65.397 

9/32 .88357 .06213 5/8 11.388 10.321 1/4 29.060 67.201 

5/16 .98175 .07670 11/16 11.585 10.680 3/8 29.452 69.029 

11/32 1.0799 .09281 3/4 11.781 11.045 1/2 29.845 70.882 

3/8 1.1781 .11045 13/16 11.977 11.416 5/8 30.238 72.760 

13/32 1.2763 .12962 7/8 12.174 11.793 3/4 30.631 74.662 

7/16 1.3744 .15033 15/16 12.370 12.177 7/8 31.023 76.589 

15/32 1.4726 .17257 4 12.566 12.566 10 31.416 78.540 

1/2 1.5708 .19635 1/16 12.763 12.962 1/8 31.809 80.516 

17/32 1.6690 .22166 1/8 12.959 13.364 1/4 32.201 82.516 

9/16 1.7671 .24850 3/16 13.155 13.772 3/8 32.594 84.541 

19/32 1.8653 .27688 1/4 13.352 14.186 1/2 32.987 86.590 

5/8 1.9635 .30680 5/16 13.548 14.607 5/8 33.379 88.664 

21/32 2.0617 .33824 3/8 13.744 15.033 3/4 33.772 90.763 

11/16 2.1598 .37122 7/16 13.941 15.466 7/8 34.165 92.886 

23/32 2.2580 .40574 1/2 14.137 15.904 11 34.558 95.033 

3/4 2.3562 .44179 9/16 14.334 16.349 1/8 34.950 97.205 

25/32 2.4544 .47937 5/8 14.530 16.800 1/4 35.343 99.402 

13/16 2.5525 .51849 11/16 14.726 17.257 3/8 35.736 101.62 

27/32 2.6507 .55914 3/4 14.923 17.721 1/2 36.128 103.87 

7/8 2.7489 .60132 13/16 15.119 18.190 5/8 36.521 106.14 

29/32 2.8471 .64504 7/8 15.315 18.665 3/4 36.914 108.43 

15/16 2.9452 .69029 15/16 15.512 19.147 7/8 37.306 110.75 

31/32 3.0434 .73708 5 15.708 19.635 12 37.699 113.10 

1 3.1416 .7854 1/16 15.904 20.129 1/8 38.092 115.47 

1/16 3.3379 .8866 1/8 16.101 20.629 1/4 38.485 117.86 

1/8 3.5343 .9940 3/16 16.297 21.135 3/8 38.877 120.28 

3/16 3.7306 1.1075 1/4 16.493 21.648 1/2 39.270 122.72 

1/4 3.9270 1.2272 5/16 16.690 22.166 5/8 39.663 125.19 

5/16 4.1233 1.3530 3/8 16.886 22.691 3/4 40.055 127.68 

3/8 4.3197 1.4849 7/16 17.082 23.221 7/8 40.448 130.19 

7/16 4.5160 1.6230 1/2 17.279 23.758 13 40.841 132.73 

1/2 4.7124 1.7671 9/16 17.475 24.301 1/8 41.233 135.30 

9/16 4.9087 1.9175 5/8 17.671 24.850 1/4 41.626 137.89 

5/8 5.1051 2.0739 11/16 17.868 25.406 3/8 42.019 140.50 

11/16 5.3014 2.2365 3/4 18.064 25.967 1/2 42.412 143.14 

3/4 5.4978 2.4053 13/16 18.261 26.535 5/8 42.804 145.80 

13/16 5.6941 2.5802 7/8 18.457 27.109 3/4 43.197 148.49 

7/8 5.8905 2.7612 15/16 18.653 27.688 7/8 43.590 151.20 

15/16 6.0868 2.9483 6 18.850 28.274 14 43.982 153.94 

2 6.2832 3.1416 1/8 19.242 29.465 1/8 44.374 156.70 

1/16 6.4795 3.3410 1/4 19.635 30.680 1/4 44.768 159.48 

1/8 6.6759 3.5466 3/8 20.028 31.919 3/8 45.160 162.30 

3/16 6.8722 3.7583 1/2 20.420 33.183 1/2 45.553 165.13 

1/4 7.0686 3.9761 5/8 20.813 34.472 5/8 45.946 167.99 

5/16 7.2649 4.2000 3/4 21.206 35.785 3/4 46.338 170.87 

3/8 7.4613 4.4301 7/8 21.598 37.122 7/8 46.731 173.78 

7/16 7.6576 4.6664 7 21.991 38.485 15 47.124 176.71 

1/2 7.8540 4.9087 1/8 22.384 39.871 1/8 47.517 179.67 

9/16 8.0503 5.1572 1/4 22.776 41.282 1/4 47.909 182.65 

5/8 8.2467 5.4119 3/8 23.169 42.718 3/8 48.302 185.66 

11/16 8.4430 5.6727 1/2 23.562 44.179 1/2 48.695 188.69 

3/4 8.6394 5.9396 5/8 23.955 45.664 5/8 49.087 191.75 

13/16 8.8357 6.2126 3/4 24.347 47.173 3/4 49.480 194.83 

7/8 9.0321 6.4918 7/8 24.740 48.707 7/8 49.873 197.93 

15/16 9.2284 6.7771 

57

CIRCUMFERENCES AND AREAS OF CIRCLES (Cont’d) 

In Inches 

Dia. Circum. Area Dia. Circum. Area Dia. Circum. Area 

16 50.265 201.06 24 75.398 452.39 39 122.522 1194.6 

1/8 50.658 204.22 1/8 75.791 457.11 40 125.664 1256.6 

1/4 51.051 207.39 1/4 76.184 461.86 41 128.805 1320.3 

3/8 51.444 210.60 3/8 76.576 466.64 42 131.947 1385.4 

1/2 51.836 213.82 1/2 76.969 471.44 43 135.088 1452.2 

5/8 52.229 217.08 5/8 77.362 476.26 44 138.230 1520.5 

3/4 52.622 220.35 3/4 77.754 481.11 45 141.372 1590.4 

7/8 53.014 223.65 7/8 78.147 485.98 46 144.513 1661.9 

17 53.407 226.98 25 78.540 490.87 47 147.655 1734.9 

1/8 53.800 230.33 1/8 78.933 495.79 48 150.796 1809.6 

1/4 54.192 233.71 1/4 79.325 500.74 49 153.939 1885.7 

3/8 54.585 237.10 3/8 79.718 505.71 50 157.080 1963.5 

1/2 54.978 240.53 1/2 80.111 510.71 51 160.221 2042.8 

5/8 55.371 243.98 5/8 80.503 515.72 52 163.363 2123.7 

3/4 55.763 247.45 3/4 80.896 520.77 53 166.504 2206.2 

7/8 56.156 250.95 7/8 81.289 525.84 54 169.646 2290.2 

18 56.549 254.47 26 81.681 530.93 55 172.788 2375.8 

1/8 56.941 258.02 1/8 82.074 536.05 56 175.929 2463.0 

1/4 57.334 261.59 1/4 82.467 541.19 57 179.071 2551.8 

3/8 57.727 265.18 3/8 82.860 546.35 58 182.212 2642.1 

1/2 58.119 268.80 1/2 83.252 551.55 59 185.354 2734.0 

5/8 58.512 272.45 5/8 83.645 556.76 60 188.496 2827.4 

3/4 58.905 276.12 3/4 84.038 562.00 61 191.637 2922.5 

7/8 59.298 279.81 7/8 84.430 567.27 62 194.779 3019.1 

19 59.690 283.53 27 84.823 572.56 63 197.920 3117.2 

1/8 60.083 287.27 1/8 85.216 577.87 64 201.062 3217.0 

1/4 60.476 291.04 1/4 85.608 583.21 65 204.204 3318.3 

3/8 60.868 294.83 3/8 86.001 588.57 66 207.345 3421.2 

1/2 61.261 298.65 1/2 86.394 593.96 67 210.487 3525.7 

5/8 61.654 302.49 5/8 86.786 599.37 68 213.628 3631.7 

3/4 62.046 306.35 3/4 87.179 604.81 69 216.770 3739.3 

7/8 62.439 310.24 7/8 85.572 610.27 70 219.911 3848.5 

20 62.832 314.16 28 87.965 615.75 71 223.053 3959.2 

1/8 63.225 318.10 1/8 88.357 621.26 72 226.195 4071.5 

1/4 63.617 322.06 1/4 88.750 626.80 73 229.336 4185.4 

3/8 64.010 326.05 3/8 89.143 632.36 74 232.478 4300.8 

1/2 64.403 330.06 1/2 89.535 637.94 75 235.619 4417.9 

5/8 64.795 334.10 5/8 89.928 643.55 76 238.761 4536.6 

3/4 65.188 338.16 3/4 90.321 649.18 77 241.903 4656.6 

7/8 65.581 342.25 7/8 90.713 654.84 78 245.044 4778.4 

21 65.973 346.36 29 91.106 660.52 79 248.186 4901.7 

1/8 66.366 350.50 1/8 91.499 666.23 80 251.327 5026.5 

1/4 66.759 354.66 1/4 91.892 671.96 81 254.469 5153.0 

3/8 67.152 358.84 3/8 92.284 677.71 82 257.611 5281.0 

1/2 67.544 363.05 1/2 92.677 683.49 83 260.752 5410.6 

5/8 67.937 367.28 5/8 93.070 689.30 84 263.894 5541.8 

3/4 68.330 371.54 3/4 93.462 695.13 85 267.035 5674.5 

7/8 68.722 375.83 7/8 93.855 700.98 86 270.177 5808.8 

22 69.115 380.13 30 94.248 706.86 87 273.319 5944.7 

1/8 69.508 384.46 1/8 94.640 712.76 88 276.460 6082.1 

1/4 69.900 388.82 1/4 95.033 718.69 89 279.602 6221.1 

3/8 70.293 393.20 3/8 95.426 724.64 90 282.743 6361.7 

1/2 70.686 397.61 1/2 95.819 730.62 91 285.885 6503.9 

5/8 71.079 402.04 5/8 96.211 736.62 92 289.027 6647.6 

3/4 71.471 406.49 3/4 96.604 742.64 93 292.168 6792.9 

7/8 71.864 410.97 7/8 96.997 748.69 94 295.310 6939.8 

23 72.257 415.48 31 97.389 754.77 95 298.451 7088.2 

1/8 72.649 420.00 32 100.531 804.25 96 301.593 7238.2 

1/4 73.042 424.56 33 103.673 855.30 97 304.734 7389.8 

3/8 73.435 429.13 34 106.814 907.92 98 307.876 7543.0 

1/2 73.827 433.74 35 109.956 962.11 99 311.018 7697.7 

5/8 74.220 438.36 36 113.097 1017.9 100 314.159 7854.0 

3/4 74.613 443.01 37 116.239 1075.2 

7/8 75.006 447.69 38 119.381 1134.1 

58

DRILL SIZE DATA 

Twist Dia. Area Twist Dia. Area Twist Dia. Area 

Drill Size In. Sq. In. Drill Size In. Sq. In. Drill Size In. Sq. In. 

– 80 .0135 .000143 – 32 .116 .0106 19/64 – .2968 .0692 

– 79 .0145 .000165 – 31 .120 .0113 – N .302 .0716 

1/64 – .0156 .00019 1/8 – .125 .0123 5/16 – .3125 .0767 

– 78 .016 .00020 – 30 .1285 .0130 – O .316 .0784 

– 77 .018 .00025 – 29 .136 .0145 – P .323 .0820 

– 76 .020 .00031 – 28 .1405 .0155 21/64 – .3281 .0846 

– 75 .021 .00035 9/64 – .1406 .0156 – Q .332 .0866 

– 74 .0225 .00040 – 27 .144 .0163 – R .339 .0901 

– 73 .024 .00045 – 26 .147 .0174 11/32 – .3437 .0928 

– 72 .025 .00049 – 25 .1495 .0175 – S .348 .0950 

– 71 .026 .00053 – 24 .152 .0181 – T .358 .1005 

– 70 .028 .00062 – 23 .154 .0186 23/64 – .3593 .1014 

– 69 .0292 .00067 5/32 – .1562 .0192 – U .368 .1063 

– 68 .030 .00075 – 22 .157 .0193 3/8 – .375 .1104 

1/32 – .0312 .00076 – 21 .159 .0198 – V .377 .1116 

– 67 .032 .00080 – 20 .161 .0203 – W .386 .1170 

– 66 .033 .00086 – 19 .166 .0216 25/64 – .3906 .1198 

– 65 .035 .00096 – 18 .1695 .0226 – X .397 .1236 

– 64 .036 .00102 11/64 – .1719 .0232 – Y .404 .1278 

– 63 .037 .00108 – 17 .175 .0235 13/32 – .4062 .1296 

– 62 .038 .00113 – 16 .177 .0246 – Z .413 .1340 

– 61 .039 .00119 – 15 .180 .0254 7/16 – .4375 .1503 

– 60 .040 .00126 – 14 .182 .0260 29/64 – .4531 .1613 

– 59 .041 .00132 – 13 .185 .0269 15/32 – .4687 .1726 

– 58 .042 .00138 3/16 – .1875 .0276 31/64 – .4843 .1843 

– 57 .043 .00145 – 12 .189 .02805 1/2 – .5000 .1963 

– 56 .0465 .00170 – 11 .191 .02865 33/64 – .5156 .2088 

3/64 – .0469 .00173 – 10 .1935 .0294 17/32 – .5312 .2217 

– 55 .0520 .00210 – 9 .196 .0302 35/64 – .5468 .2349 

– 54 .0550 .0023 – 8 .199 .0311 9/16 – .5625 .2485 

– 53 .0595 .0028 – 7 .201 .0316 37/64 – .5781 .2625 

1/16 – .0625 .0031 13/64 – .2031 .0324 19/32 – .5937 .2769 

– 52 .0635 .0032 – 6 .204 .0327 39/64 – .6093 .2916 

– 51 .0670 .0035 – 5 .2055 .0332 5/8 – .625 .3068 

– 50 .070 .0038 – 4 .209 .0343 41/64 – .6406 .3223 

– 49 .073 .0042 – 3 .213 .0356 21/32 – .6562 .3382 

– 48 .076 .0043 7/32 – .2187 .0376 43/64 – .6718 .3545 

5/64 – .0781 .0048 – 2 .221 .0384 11/16 – .6875 .3712 

– 47 .0785 .0049 – 1 .228 .0409 45/64 – .7031 .3883 

– 46 .081 .0051 – A .234 .0430 23/32 – .7187 .4057 

– 45 .082 .0053 15/64 – .2343 .0431 47/64 – .7343 .4236 

– 44 .086 .0058 – B .238 .0444 3/4 – .750 .4418 

– 43 .089 .0062 – C .242 .0460 49/64 – .7656 .4604 

– 42 .0935 .0069 – D .246 .0475 25/32 – .7812 .4794 

3/32 – .0937 .0069 1/4 E .250 .0491 51/64 – .7968 .4987 

– 41 .096 .0072 – F .257 .0519 13/16 – .8125 .5185 

– 40 .098 .0075 – G .261 .0535 53/64 – .8281 .5386 

– 39 .0995 .0078 17/64 – .2656 .0554 27/32 – .8337 .5591 

– 38 .1015 .0081 – H .266 .0556 55/64 – .8593 .5800 

– 37 .104 .0085 – I .272 .0580 7/8 – .875 .6013 

– 36 .1065 .0090 – J .277 .0601 

7/64 – .1093 .0094 – K .281 .0620 

– 35 .110 .0095 9/32 – .2812 .0621 

– 34 .111 .0097 – L .290 .0660 

– 33 .113 .0100 – M .295 .0683 

59

Taps for Machine Threads – Drill sizes for 75% of full 

thread 

Thread Tap Drill Thread Tap Drill 

Size Size Size Size 

6-32 NC 36 3/8-16 NC 5/16 

6-40 NF 34 3/8-24 NF Q 

8-32 NC 30 7/16-14 NC U 

8-36 NF 29 7/16-20 NF W 

10-24 NC 25 1/2-13 NC .425 

10-32 NF 21 1/2-20 NF 29/64 

12-24 NC 17 9/16-12 NC 31/64 

12-28 NF 15 9/16-18 NF .508 

1/4-20 NC 7 5/8-11 NC 17/32 

1/4-28 NF 3 5/8-18 NF .571 

5/16-18 NC F 3/4-10 NC 21/32 

5/16-24 NF I 3/4-16 NF 11/16 

7/8-9 NC 49/64 

7/8-14 NF .805 

1-8 NC 7/8 

See page 59 for diameters of numbered and lettered 

tap drills. 

TAP DRILL SIZES 

60 

Pipe Taps – American Standard and Dryseal Pipe 

Threads 

Pipe Threads Tap Pipe Threads Tap 

Size, Per Drill Size Per Drill 

Inches Inch Size Inches Inch Size 

1/8 27 11/32 2 11-1/2 2-7/32 

1/4 18 7/16 2-1/2 8 2-5/8 

3/8 18 9/16 3 8 3-1/4 

1/2 14 45/64 4 8 4-1/4 

3/4 14 29/32 5 8 5-5/16 

1 11-1/2 1-9/64 6 8 6-3/8 

1-1/4 11-1/2 1-31/64 8 8 8-3/8 

1-1/2 11-1/2 1-47/64 

DRILLING TEMPLATES – PIPE FLANGES 

Drilling template dimensions of Class 150 pipe flanges per 

ANSI B 16.5 – 1981. 

A - O.D. 

B - Bolt Circle 

Diameter 

C - Bolt Hole Diameter 

N - Number of Bolt Holes 

Nominal All dimensions in inches 

Pipe Bolt 

Size A B C N Diameter 

1/2 3.50 2.38 .62 4 1/2 

3/4 3.88 2.75 .62 4 1/2 

1 4.25 3.12 .62 4 1/2 

1-1/4 4.62 3.50 .62 4 1/2 

1-1/2 5.00 3.88 .62 4 1/2 

2 6.00 4.75 .75 4 5/8 

2-1/2 7.00 5.50 .75 4 5/8 

3 7.50 6.00 .75 4 5/8 

4 9.00 7.50 .75 8 5/8 

6 11.00 9.50 .88 8 3/4 

8 13.50 11.75 .88 8 3/4 

10 16.00 14.25 1.00 12 7/8 

12 19.00 17.00 1.00 12 7/8 

14 21.00 18.75 1.12 12 1 

16 23.50 21.25 1.12 16 1 

18 25.00 22.75 1.25 16 1-1/8 

20 27.50 25.00 1.25 20 1-1/8 

24 32.00 29.50 1.38 20 1-1/4

CHAPTER 10 – ABBREVIATIONS & SYMBOLS 

A – ampere(s), area 

A, C, or a-c – alternating current 

acfh – actual cubic feet per hour 

acfm – actual cubic feet per minute 

ANSI – American National Standards Institute 

API – American Petroleum Institute 

°API – degrees API (a measurement of fuel oil specific gravity) 

ASTM – American Society for Testing and Materials 

AWG – American Wire Gauge 

Btu – British thermal unit 

BWG – Birmginham Wire Gauge 

C or °C – degrees Celsius or Centigrade 

Cal – kilogram-calorie or kilo-calorie (equals 1000 calories) 

cal – calorie 

Cd – coefficient of discharge 

cfh – cubic feet per hour 

cfm – cubic feet per minute 

CL – centerline 

cm – centimeter(s) 

cs or cSt – centistoke(s) 

cu ft – cubic feet 

cu in – cubic inches 

cu m – cubic meters 

C v - flow coefficient or flow factor (for valve capacities) 

D or d – density, diameter 

D.C. or d-c – direct current 

deg – degree(s) 

dia – diameter 

e - emissivity 

°E – degrees Engler (a measurement of fuel oil viscosity) 

F or °F – degrees Fahrenheit 

f – convection film coefficient 

F.B. – firebrick 

fpm – feet per minute 

fps – feet per second 

ft – foot or feet 

G or g – gravity or specific gravity 

gal – gallon(s) 

gph – gallons per hour 

gpm – gallons per minute 

h - pressure drop 

h f – heat content of liquid (water & steam) 

h fg – latent heat of vaporization, water to steam 

h g – heat content of vapor (steam) 

"Hg – inches of mercury column 

HL – heat loss 

HP or hp – horsepower 

hr – hour(s) 

HS – heat storage 

Hz – Hertz (cycles per second in alternating current) 

ID or id – inside diameter 

I.F.B. – insulating firebrick 

in – inch(es) 

in 2 – square inch(es) 

ABBREVIATIONS 

61 

in 3 – cubic inch(es) 

JIC – Joint Industrial Council 

K – Stefan – Boltzmann constant 

k – thermal conductivity 

°K – degrees Kelvin 

kcal – kilogram-calorie or kilo-calorie (same as Cal) 

kPa – kiloPascal 

kVA – kilo volt – amperes 

L – length or thickness 

lb – pound(s) 

LPG – liquified petroleum gas 

mbar – millibar(s) 

mmHg – millimeters of mercury column 

mmw.c. – millimeters of water column 

N.C. – normally closed 

NEMA – National Electrical Manufacturers Association 

NFPA – National Fire Protection Association 

N.O. – normally open 

OD or od – outside diameter 

osi – ounces per square inch 

oz – ounce(s) 

P – pressure or pressure drop 

psi – pounds per square inch 

psia – pounds per square inch, absolute 

psig – pounds per square inch, gauge 

Pv – velocity pressure 

Q – flow (of gases, liquids, or heat) 

°R – degrees Rankine 

rpm – revolutions per minute 

scfh – standard cubic feet per hour 

scfm – standard cubic feet per minute 

sec – second 

S.G. or sg – specific gravity 

sp ht – specific heat 

sp gr – specific gravity 

sq ft – square feet 

sq in – square inch(es) 

SR1 – seconds Redwood #1 (a measurement of fuel oil viscosity) 

SSF – seconds Saybolt Furol (a measurement of fuel oil viscosity) 

SSU – seconds Saybolt Universal (a measurement of fuel oil 

viscosity) 

T or t – temperature 

T abs – absolute temperature 

TC – cold face temperature or thermocouple 

V – vacuum, volts, or volume 

V g – specific volume of water vapor 

W – flow rate 

"w.c. – inches of water column 

"w.g. – inches of water gauge (same as "w.c.) 

wt – weight

CR 

M 

CH 

ELECTRICAL SYMBOLS 

Shown below are graphic symbols commonly used in JICtype 

ladder diagrams for combustion control systems. For 

a complete list of symbols, refer to JIC Electrical Standard 

EMP-1. 

Description Symbol Description Symbol Description Symbol 

Coils 

–Relays (CR) 

–Timers (TR) 

– Motor Starters (M) 

– Contactors (CON) 

Coils 

–Solenoids 

Conductors 

–Not Connected 

–Connected 

Connections 

–Ground 

–Chassis or 

Frame (not 

necessarily 

grounded) 

–Plug and 

Receptacle 

Contacts 

–Time Delay 

After Coil 

Energized 

–N.O. 

–N.C. 

–Time Delay 

After Coil 

De-energized 

–N.O. 

–N.C. 

SOL 

GRD 

PL 

RECP 

TR 

TR 

TR 

TR 

TR 

CON 

Contacts 

– Relays (CR) 

– Motor Starters (M) 

– Contactors (CON) 

– N.O. 

– N.C. 

Contacts 

–Thermal Overload 

–Overload Relay 

(OL) 

–Instataneous 

Overload (IOL) 

Control Circuit 

Transformer 

Fuses – All 

Types 

Horn or Siren 

(Alarm) 

Meters 

–Volt 

–Amp 

Motors 

–3 Phase 

–D.C . 

Potentiometer 

62 

H1 H3 H2 H4 

X1 X2 

MTR 

CR M 

CON 

CR M 

CON 

OL 

IOL 

FU 

AH 

VM 

AM 

MTR 

A 

POT 

T 

Pilot Light 

(Letter denotes 

color) 

Pilot Light– 

Push to Test 

(Letter denotes 

color) 

Pushbutton 

–Single 

Circuit, N.O. 

–Single 

Circuit, N.C. 

–Double 

Circuit 

–Double 

Circuit, 

Mushroom 

Head 

–Maintained 

Contact 

Switches 

– Disconnect 

– Circuit 

Interruptor 

– Circuit 

Breaker 

LT 

CB 

PB 

LT 

R 

PB 

PB 

PB 

R 

PB 

DISC 

CI 

PB

ELECTRICAL SYMBOLS (Cont’d) 

Description Symbol Description Symbol Description Symbol 

Switch, Limit 

— N.O. 

— Held Closed 

— N.C. 

— Held Open 

— Neutral 

Position, 

— Neutral 

Position, 

Actuated 

Switch, Liquid 

Level 

— N.O. 

— N.C. 

NP 

NP 

LS 

LS 

LS 

LS 

LS 

LS 

FS 

FS 

Switch, Selector 

— 2 Position 

— 3 Position 

Switch, 

Temperature 

— N.O. 

— N.C. 

Switch, 

Toggle 

63 

SS 

1 2 

1 

SS 

2 

TAS 

TAS 

TGS 

3 

Switch, Vacuum 

or Pressure 

— N.O. 

— N.C. 

Thermal Overload 

Element 

— Overload (OL) 

— Instantaneous 

Overload (IOL) 

Thermocouple 

PS 

PS 

OL 

IOL 

T/C

CHAPTER 11 – CONVERSION FACTORS 

MULTIPLY BY TO OBTAIN 

atmospheres . . . . . . . . .33.90 . . . . . . . . . . . . . . .Feet of H2O 29.92 . . . . . . . . . . . . . .Inches of Hg 

14.70 . . . . . . . . . . . . . . . . . . . . . .Psi 

1013.2 . . . . . . . . . . . . . . . . . .Millibars 

760.0 . . . . . . . . . . . . . . . .mm. of Hg 

1.058 . . . . . . . . . . . . . . . .Tons/sq..ft 

1.033 . . . . . . . . . . . . . . .Kg./sq. cm. 

barrels (oil) . . . . . . . . . . . .42 . . . . . . . . . . . . . . .Gallons (oil) 

bars . . . . . . . . . . . . . . ..9869 . . . . . . . . . . . . . .Atmospheres 

1020 . . . . . . . . . . . . . .kg./sq. meter 

btu . . . . . . . . . . . . . . . .778.2 . . . . . . . . . . . . . . .foot-pounds 

252 . . . . . . . . . . . . .gram-calories 

.000393 . . . . . . . . . .horsepower-hours 

1055 . . . . . . . . . . . . . . . . . . .joules 

.252 . . . . . . . . . . .kilogram-calories 

.000293 . . . . . . . . . . . . .kilowatt-hours 

btu/cu. ft. . . . . . . . . . . . . . .8.9 . . . . . . . . . .kilogram-calories/ 

cu. meter 

btu/hr . . . . . . . . . . . . . . ..216 . . . . . . . . . . . . .ft.-pounds/sec. 

.007 . . . . . . . . . . . . .gram-cal./sec. 

.000393 . . . . . . . . . . . . . . .horsepower 

.293 . . . . . . . . . . . . . . . . . . . .watts 

btu ft./hr. sq. ft. °F . . . . .14.88 . . . . . . . .Cal-cm/hr. sq. cm °C 

8890.0 . . . . . . . . . .Cal. gm/cu. meter 

btu/lb . . . . . . . . . . . . . .0.556 . . . . . . . . . . . . . . .calories/gm. 

btu/lb. °F . . . . . . . . . . . . . .1.0 . . . . . . . . . . . . .calories/gm °C 

btu/sec. . . . . . . . . . . . . .1.055 . . . . . . . . . . . . . . . . . . . . .kW 

btu/sq. ft.-min . . . . . . . . . .122 . . . . . . . . . . . . . . .watts/sq. in. 

calories-gram . . . . . . ..00397 . . . . . . . . . . . . . . . . . . . . .Btu 

calorie-Kg . . . . . . . . . . . .3.97 . . . . . . . . . . . . . . . . . . . . .Btu 

calorie-Kg/cu. meter 0.1124 . . . . . . . . . . . . . . .Btu/cu. ft. @ 

. . . . . . . . . . . . . .32°F 30" Hg 

calorie/hr. sq. cm. . . . . .3.687 . . . . . . . . . . . . .Btu/hr. sq. foot 

centiliters . . . . . . . . . . . ..001 . . . . . . . . . . . . . . . . . . . .liters 

centimeters . . . . . . . . . ..0328 . . . . . . . . . . . . . . . . . . . . .feet 

.0394 . . . . . . . . . . . . . . . . . . .inches 

.00001 . . . . . . . . . . . . . . . .kilometers 

.01 . . . . . . . . . . . . . . . . . . .meters 

.0000062 . . . . . . . . . . . . . . . . . . . .miles 

10 . . . . . . . . . . . . . . . .millimeters 

393.7 . . . . . . . . . . . . . . . . . . . . .mils 

.0109 . . . . . . . . . . . . . . . . . . . .yards 

1000 . . . . . . . . . . . . . . . . . .microns 

centimeters of mercury ..0132 . . . . . . . . . . . . . .atmospheres 

.446 . . . . . . . . . . . . . . . .ft. of water 

136 . . . . . . . . . . . . . .kg./sq. meter 

27.85 . . . . . . . . . . . . . .pounds/sq. ft. 

.193 . . . . . . . . . . . . .pounds/sq. in. 

centimeters/sec. . . . . . .1.969 . . . . . . . . . . . . . . . . .feet/min. 

.0328 . . . . . . . . . . . . . . . . .feet/sec. 

.036 . . . . . . . . . . . . . .kilometers/hr. 

6 . . . . . . . . . . . . . . .meters/min. 

.0224 . . . . . . . . . . . . . . . . . .miles/hr. 

.00373 . . . . . . . . . . . . . . . .miles/min. 

centimeters/sec./sec. . ..0328 . . . . . . . . . . . . . . .ft./sec./sec. 

.036 . . . . . . . . . . . . . . .kms./hr.sec. 

.01 . . . . . . . . . . . .meters/sec.sec. 

.0224 . . . . . . . . . . . . . .miles/hr.sec. 

centipoise . . . . . . . . . . . . ..01 . . . . . . . . . . . . . . .gr.cm.-sec. 

.00067 . . . . . . . . . . . . .pound/ft.-sec. 

2.4 . . . . . . . . . . . . . . .pound/ft.-hr. 

GENERAL CONVERSION FACTORS 

64 


circular mils . . . . . ..00000507 . . . . . . . . . . . . . . . . . . .sq.cm. 

.785 . . . . . . . . . . . . . . . . . . .sq.mils 

.000000785 . . . . . . . . . . . . . . . .sq. inches 

cubic centimeters . ..0000353 . . . . . . . . . . . . . . . . . .cubic ft. 

.061 . . . . . . . . . . . . . . . . . .cubic in. 

.000001 . . . . . . . . . . . . . .cubic meters 

.00000131 . . . . . . . . . . . . . . .cubic yards 

.000264 . . . . . . . . .gallons (U.S. liquid) 

.001 . . . . . . . . . . . . . . . . . . . .liters 

.00211 . . . . . . . . . . .pints (U.S. liquid) 

00106 . . . . . . . . . .quarts (U.S. liquid) 

cubic feet . . . . . . . . . . .28320 . . . . . . . . . . . . . . . . . .cu. cms. 

1728 . . . . . . . . . . . . . . . .cu. inches 

.028 . . . . . . . . . . . . . . . .cu. meters 

.037 . . . . . . . . . . . . . . . . .cu. yards 

7.48 . . . . . . . . .gallons (U.S. liquid) 

28.32 . . . . . . . . . . . . . . . . . . . .liters 

59.84 . . . . . . . . . . .pints (U.S. liquid) 

29.92 . . . . . . . . . .quarts (U.S. liquid) 

cubic feet/min. . . . . . . . . .472 . . . . . . . . . . . . . .cu. cms./sec. 

.125 . . . . . . . . . . . . . . .gallons/sec. 

.472 . . . . . . . . . . . . . . . . .liters/sec. 

62.43 . . . . . . . . . .pounds water/min. 

cubic inches . . . . . . . . .16.39 . . . . . . . . . . . . . . . . . .cu. cms. 

.000579 . . . . . . . . . . . . . . . . . . . .cu. ft. 

.0000164 . . . . . . . . . . . . . . . .cu. meters 

.0000214 . . . . . . . . . . . . . . . . .cu. yards 

.00433 . . . . . . . . . . . . . . . . . .gallons 

.0164 . . . . . . . . . . . . . . . . . . . .liters 

.0346 . . . . . . . . . . .pints (U.S. liquid) 

.0173 . . . . . . . . . .quarts (U.S. liquid) 

cubic meters . . . . .1,000,000 . . . . . . . . . . . . . . . . . .cu. cms. 

35.31 . . . . . . . . . . . . . . . . . . . .cu. ft. 

6102 . . . . . . . . . . . . . . . .cu. inches 

1.308 . . . . . . . . . . . . . . . . .cu. yards 

264.2 . . . . . . . . .gallons (U.S. liquid) 

1000 . . . . . . . . . . . . . . . . . . . .liters 

2113 . . . . . . . . . . .pints (U.S. liuqid) 

1057 . . . . . . . . . .quarts (U.S. liquid) 

cubic yards . . . . . . . .764,600 . . . . . . . . . . . . . . . . . .cu. cms. 

27 . . . . . . . . . . . . . . . . . . . .cu. ft. 

46656 . . . . . . . . . . . . . . . .cu. inches 

.765 . . . . . . . . . . . . . . . .cu. meters 

decigrams . . . . . . . . . . . . . ..1 . . . . . . . . . . . . . . . . . . .grams 

deciliters . . . . . . . . . . . . . . ..1 . . . . . . . . . . . . . . . . . . . .liters 

decimeters . . . . . . . . . . . . ..1 . . . . . . . . . . . . . . . . . . .meters 

degrees (angle) . . . . . . ..011 . . . . . . . . . . . . . . . .quadrants 

.0175 . . . . . . . . . . . . . . . . . .radians 

3600 . . . . . . . . . . . . . . . . .seconds 

degrees/sec. . . . . . . . . ..0175 . . . . . . . . . . . . . . .radians/sec. 

.0167 . . . . . . . . . . . . .rvolutions/min. 

.00278 . . . . . . . . . . . .revolutions/sec. 

dekagrams . . . . . . . . . . . .10 . . . . . . . . . . . . . . . . . . .grams 

dekaliters . . . . . . . . . . . . . .10 . . . . . . . . . . . . . . . . . . . .liters 

dekameters . . . . . . . . . . . .10 . . . . . . . . . . . . . . . . . . .meters 

dynes/sq. cm. . . ..000000987 . . . . . . . . . . . . . .atmospheres 

.0000295 . . . . . .in. of mercury (at 0°C.) 

.000402 . . . . . . . . .in. of water (at 4°C) 

.00001 . . . . . . . . . . . . . . . . . . . . .bars 

feet . . . . . . . . . . . . . . . .30.48 . . . . . . . . . . . . . . .centimeters 

.000305 . . . . . . . . . . . . . . . .kilometers 

.305 . . . . . . . . . . . . . . . . . . .meters 

.000189 . . . . . . . . . . . . . . .miles (stat.) 

304.8 . . . . . . . . . . . . . . . .millimeters

GENERAL CONVERSION FACTORS (Cont’d) 


feet of water . . . . . . . . ..0295 . . . . . . . . . . . . . .atmospheres 

.883 . . . . . . . . . . . . .in. of mercury 

.0305 . . . . . . . . . . . . . . .kgs./sq. cm. 

304.8 . . . . . . . . . . . . .kgs./sq. meter 

62.43 . . . . . . . . . . . . . .pounds/sq. ft. 

.434 . . . . . . . . . . . . .pounds/sq. in. 

feet/min. . . . . . . . . . . . . ..508 . . . . . . . . . . . . . . . . .cms./sec. 

.0167 . . . . . . . . . . . . . . . . .feet/sec. 

.0183 . . . . . . . . . . . . . . . . . .kms./hr. 

.305 . . . . . . . . . . . . . . .meters/min. 

.0114 . . . . . . . . . . . . . . . . . .miles/hr. 

30.48 . . . . . . . . . . . . . . . . .cms./sec. 

feet/sec. . . . . . . . . . . . .1.097 . . . . . . . . . . . . . . . . . .kms./hr. 

18.29 . . . . . . . . . . . . . . .meters/min. 

.682 . . . . . . . . . . . . . . . . . .miles/hr. 

.0114 . . . . . . . . . . . . . . . .miles/min. 

feet/sec./sec. . . . . . . . .30.48 . . . . . . . . . . . . .cms./sec./sec. 

1.097 . . . . . . . . . . . . . .kms./hr./sec. 

.305 . . . . . . . . . . .meters/sec./sec. 

foot-pounds . . . . . . . . ..00129 . . . . . . . . . . . . . . . . . . . . . .btu 

.324 . . . . . . . . . . . . .gram-calories 

.000000505 . . . . . . . . . . .horsepower-hrs. 

1.356 . . . . . . . . . . . . . . . . . . .joules 

.000324 . . . . . . . . . . . . . . .kg.-calories 

.138 . . . . . . . . . . . . . . . .kg.-meters 

.000000377 . . . . . . . . . . . . . . .kilowatt-hrs. 

foot-pounds/sec. . . . . . . .4.63 . . . . . . . . . . . . . . . . . . .btu/hr. 

.0772 . . . . . . . . . . . . . . . . . .btu/min. 

.00182 . . . . . . . . . . . . . . .horsepower 

.00195 . . . . . . . . . . .kg.-calories/min. 

.00136 . . . . . . . . . . . . . . . . .kilowatts 

.00001 . . . . . . . . . . . . . . . .kilometers 

gallons . . . . . . . . . . . . . .3785 . . . . . . . . . . . . . . . . . .cu. cms. 

.134 . . . . . . . . . . . . . . . . . .cu. feet 

231 . . . . . . . . . . . . . . . .cu. inches 

.00379 . . . . . . . . . . . . . . . .cu. meters 

.00495 . . . . . . . . . . . . . . . . .cu. yards 

3.785 . . . . . . . . . . . . . . . . . . . .liters 

gallons (liq. Br. imp.) . . .1.201 . . . . . . . . .gallons (U.S. liuqid) 

gallons (U.S.) . . . . . . . . ..833 . . . . . . . . . . . . . .gallons (imp.) 

gallons of water . . . . . . .8.34 . . . . . . . . . . . . . .gallons (imp.) 

gallons/min. . . . . . . . ..00223 . . . . . . . . . . . . . . .cu. feet/sec. 

.0631 . . . . . . . . . . . . . . . . .liters/sec. 

8.021 . . . . . . . . . . . . . . . .cu. feet/hr. 

grains (troy) . . . . . . . . . . . . .1 . . . . . . . . . . . . .grains (avdp.) 

.0648 . . . . . . . . . . . . . . . . . . .grams 

.00208 . . . . . . . . . . . . .ounces (avdp.) 

grams . . . . . . . . . . . . . .15.43 . . . . . . . . . . . . . . .grains (troy) 

.0000981 . . . . . . . . . . . . . . . .joules/cm. 

.00981 . . . . . .joules/meter (newtons) 

.001 . . . . . . . . . . . . . . . . .kilograms 

1000 . . . . . . . . . . . . . . . .milligrams 

.0353 . . . . . . . . . . . . . .ounces (troy) 

.00221 . . . . . . . . . . . . . . . . . .pounds 

grams/cu. cm. . . . . . . . .62.43 . . . . . . . . . . . . . .pounds/cu. ft. 

.0361 . . . . . . . . . . . . .pounds/cu. in. 

grams/liter . . . . . . . . . . .58.42 . . . . . . . . . . . . . . . .grains/gal. 

8.345 . . . . . . . . . .pounds/1,000 gal. 

.0624 . . . . . . . . . . . . . .pounds/cu. ft. 

65 


grams/sq. cm. . . . . . . . .2.048 . . . . . . . . . . . . . .pounds/sq. ft. 

gram-calories . . . . . . ..00397 . . . . . . . . . . . . . . . . . . . . . .btu 

3.086 . . . . . . . . . . . . . . .foot-pounds 


.00000116 . . . . . . . . . . . . . . .kilowatt-hrs. 

.00116 . . . . . . . . . . . . . . . . .watt-hrs. 

gram-calories/sec. . . . .14.29 . . . . . . . . . . . . . . . . . . .btu/hr. 

hectares . . . . . . . . . . . .2.471 . . . . . . . . . . . . . . . . . . . .acres 

10760 . . . . . . . . . . . . . . . . . .sq. feet 

hectograms . . . . . . . . . . .100 . . . . . . . . . . . . . . . . . . .grams 

hectoliters . . . . . . . . . . . .100 . . . . . . . . . . . . . . . . . . . .liters 

hectometers . . . . . . . . . . .100 . . . . . . . . . . . . . . . . . . .meters 

hectowatts . . . . . . . . . . . .100 . . . . . . . . . . . . . . . . . . . .watts 

horsepower . . . . . . . . . .42.44 . . . . . . . . . . . . . . . . . .btu/min. 

33000 . . . . . . . . . . . . . .foot-lbs./min. 

550 . . . . . . . . . . . . . .foot-lbs./sec. 

horsepower (metric) . . . ..986 . . . . . . . . . . . . . . .horsepower 

horsepower . . . . . . . . ..1.014 . . . . . . . .horsepower (metric) 

10.68 . . . . . . . . . . .kg.-calories/min. 

.746 . . . . . . . . . . . . . . . . .kilowatts 

745.7 . . . . . . . . . . . . . . . . . . . .watts 

horsepower-hours . . . . ..2547 . . . . . . . . . . . . . . . . . . . . . .btu 

1,980,000 . . . . . . . . . . . . . . . . . .foot-lbs. 

641,190 . . . . . . . . . . . . . .gram-caloies 

2,684,000 . . . . . . . . . . . . . . . . . . .joules 

641.7 . . . . . . . . . . . . . . .kg.-calories 

273,700 . . . . . . . . . . . . . . . .kg.-meters 

.746 . . . . . . . . . . . . . . .kilowatt-hrs. 

hours . . . . . . . . . . . . . ..0417 . . . . . . . . . . . . . . . . . . . .days 

.00595 . . . . . . . . . . . . . . . . . . .weeks 

25.4 . . . . . . . . . . . . . . . .millimeters 

1000 . . . . . . . . . . . . . . . . . . . . .mils 

.0278 . . . . . . . . . . . . . . . . . . . .yards 

in. of mercury . . . . . . . ..0334 . . . . . . . . . . . . . .atmospheres 

1.133 . . . . . . . . . . . . . .feet of water 

.0345 . . . . . . . . . . . . . . .kgs./sq. cm. 

345.3 . . . . . . . . . . . . .kgs./sq. meter 

70.73 . . . . . . . . . . . . . .pounds/sq. ft 

.491 . . . . . . . . . . . . .pounds/sq. in. 

in. of water (at 4°C) . . ..00246 . . . . . . . . . . . . . .atmospheres 

.0736 . . . . . . . . . .inches of mercury 

.00254 . . . . . . . . . . . . . . .kgs./sq. cm. 

.578 . . . . . . . . . . . . .ounces/sq. in. 

5.204 . . . . . . . . . . . . . .pounds/sq. ft. 

.0361 . . . . . . . . . . . . .pounds/sq. in. 

joules . . . . . . . . . . . ..000949 . . . . . . . . . . . . . . . . . . . . . .btu 

.774 . . . . . . . . . . . . . . .foot-pounds 

.000239 . . . . . . . . . . . . . . .kg.-calories 

.102 . . . . . . . . . . . . . . . .kg.-meters 

.000278 . . . . . . . . . . . . . . . . .watt-hrs. 

kilograms . . . . . . . . . . . .1000 . . . . . . . . . . . . . . . . . . .grams 

.0981 . . . . . . . . . . . . . . . .joules/cm. 

9.807 . . . . . .joules/meter (newtons) 

2.205 . . . . . . . . . . . . . . . . . .pounds 

.000984 . . . . . . . . . . . . . . . .tons (long) 

.00110 . . . . . . . . . . . . . . .tons (short) 

35.27 . . . . . . . . . . . . .ounces (avdp.)


MULTIPLY BY TO OBTAIN MULTIPLY BY TO OBTAIN 

kilograms/cu. meter . . . . ..001 . . . . . . . . . . . . .grams/cu. cm. meters . . . . . . . . . . . . . . .100 . . . . . . . . . . . . . . .centimeters 

.0624 . . . . . . . . . . . . . .pounds/cu. ft 

3.281 . . . . . . . . . . . . . . . . . . . . .feet 

.0000361 . . . . . . . . . . . . .pounds/cu. in. 

39.37 . . . . . . . . . . . . . . . . . . .inches 

kilograms/sq. cm. . . . .980665 . . . . . . . . . . . . .dynes/sq. cm. 

.968 . . . . . . . . . . . . . .atmospheres 

32.81 . . . . . . . . . . . . . .feet of water 

28.96 . . . . . . . . . .inches of mercury 

2048 . . . . . . . . . . . . . .pounds/sq. ft. 

14.22 . . . . . . . . . . . . .pounds/sq. in. 

kilograms/sq. meter ..0000968 . . . . . . . . . . . . . .atmospheres 

.0000981 . . . . . . . . . . . . . . . . . . . . .bars 

.00328 . . . . . . . . . . . . . .feet of water 


.205 . . . . . . . . . . . . . .pounds/sq. ft. 

.00142 . . . . . . . . . . . . .pounds/sq. in. 

98.07 . . . . . . . . . . . . .dynes/sq. cm. 

kilograms/sq. mm . .1,000,000 . . . . . . . . . . . . .kgs./sq. meter 

kilogram-calories . . . . . .3.968 . . . . . . . . . . . . . . . . . . . . . .btu 

3086 . . . . . . . . . . . . . . .foot-pounds 


4183 . . . . . . . . . . . . . . . . . . .joules 

1163 . . . . . . . . . . . . . . .kilowatt-hrs. 

kilogram-meters . . . . . .7.233 . . . . . . . . . . . . . . .foot-pounds 

.001 . . . . . . . . . . . . . . . .kilometers 

.00054 . . . . . . . . . . . .miles (nautical) 

.000621 . . . . . . . . . . . . .miles (statute) 

1000 . . . . . . . . . . . . . . . .millimeters 

1.094 . . . . . . . . . . . . . . . . . . . .yards 

meters/min. . . . . . . . . . .1.667 . . . . . . . . . . . . . . . . .cms./sec. 

3.281 . . . . . . . . . . . . . . . . .feet/min. 

.0547 . . . . . . . . . . . . . . . . .feet/sec. 

.06 . . . . . . . . . . . . . . . . . .kms./hr. 

.0373 . . . . . . . . . . . . . . . . . .miles/hr. 

meters/sec. . . . . . . . . . .196.8 . . . . . . . . . . . . . . . . .feet/min. 

3.281 . . . . . . . . . . . . . . . . .feet/sec. 

3.6 . . . . . . . . . . . . . .kilometers/hr. 

.06 . . . . . . . . . . . .kilometers/min. 

2.237 . . . . . . . . . . . . . . . . . .miles/hr. 

.0373 . . . . . . . . . . . . . . . .miles/min. 

meters/sec./sec. . . . . . . .100 . . . . . . . . . . . . .cms./sec./sec. 

3.281 . . . . . . . . . . . . . . .ft./sec./sec. 

3.6 . . . . . . . . . . . . . . .kms./hr.sec. 

9.807 . . . . . . . . . . . . . . . . . . .joules 

2.237 . . . . . . . . . . . . . .miles/hr./sec. 

.00234 . . . . . . . . . . . . . . .kg.-calories micrograms . . . . . . . ..000001 . . . . . . . . . . . . . . . . . . .grams 

.00000272 . . . . . . . . . . . . . . .kilowatt-hrs. micrograms/cu. ft. . . ..000001 . . . . . . . . . . . . . . .grams/cu. ft 

kiloliters . . . . . . . . . . . . .1000 . . . . . . . . . . . . . . . . . . . .liters 

.0000353 . . . . . . . . . . .grams/cu. meter 

kilometers . . . . . . . . .100,000 . . . . . . . . . . . . . . .centimeters 

.00000022 . . . . . . . . . . . .lbs./1000 cu. ft. 

3281 . . . . . . . . . . . . . . . . . . . . .feet 

35.314 . . . . . . .micrograms/cu. meter 

39,370 . . . . . . . . . . . . . . . . . . .inches micrograms/cu. m. . . . .0.001 . . . . . . . . . . .milligrams/cu. m. 

1000 . . . . . . . . . . . . . . . . . . .meters 

0.02832 . . . . . . . . . . .micrograms/cu. ft 

.621 . . . . . . . . . . . . .miles (statute) 


1,000,000 . . . . . . . . . . . . . . . .millimeters 

1093.6 . . . . . . . . . . . . . . . . . . . .yards 

kilometers/hr. . . . . . . . .27.78 . . . . . . . . . . . . . . . . .cms./sec. 

54.68 . . . . . . . . . . . . . . . . .feet/min. 

.911 . . . . . . . . . . . . . . . . .feet/sec. 

kilowatts . . . . . . . . . . . . .3413 . . . . . . . . . . . . . . . . . . . .btu/hr 

44,260 . . . . . . . . . . . . . .foot-lbs./min. 

737.6 . . . . . . . . . . . . . . .foot-lbs.sec. 

1.341 . . . . . . . . . . . . . . .horsepower 

14.34 . . . . . . . . . . .kg.-calories/min. 

1000 . . . . . . . . . . . . . . . . . . . .watts 

kilowatt-hrs. . . . . . . . . . .3413 . . . . . . . . . . . . . . . . . . . . . .btu 

2,655,000 . . . . . . . . . . . . . . . . . .foot-lbs. 

859,850 . . . . . . . . . . . . . .gram calories 

1.341 . . . . . . . . . .horsepower-hours 

3,600,000 . . . . . . . . . . . . . . . . . . .joules 

860.5 . . . . . . . . . . . . . . .kg.-calories 

367,100 . . . . . . . . . . . . . . . .kg.-meters 

microhms . . . . . . . . ..000001 . . . . . . . . . . . . . . . . . . . .ohms 

microliters . . . . . . . . ..000001 . . . . . . . . . . . . . . . . . . . .liters 

micromicrons ..000000000001 . . . . . . . . . . . . . . . . . . .meters 

microns . . . . . . . . . . ..000001 . . . . . . . . . . . . . . . . . . .meters 

miles (statute) . . . . . .160,900 . . . . . . . . . . . . . . .centimeters 

5280 . . . . . . . . . . . . . . . . . . . . .feet 

63360 . . . . . . . . . . . . . . . . . . .inches 

1.609 . . . . . . . . . . . . . . . .kilometers 

1609 . . . . . . . . . . . . . . . . . . .meters 


1760 . . . . . . . . . . . . . . . . . . . .yards 

miles/hr. . . . . . . . . . . . .44.70 . . . . . . . . . . . . . . . . .cms./sec. 

88 . . . . . . . . . . . . . . . . . . .ft./min. 

1.467 . . . . . . . . . . . . . . . . . . .ft./sec. 

1.609 . . . . . . . . . . . . . . . . . .kms./hr. 

.0268 . . . . . . . . . . . . . . . . .kms./min. 

26.82 . . . . . . . . . . . . . . .meters/min. 

.0167 . . . . . . . . . . . . . . . .miles/min. 

milligrams . . . . . . . . . . . ..001 . . . . . . . . . . . . . . . . . . .grams 

3.53 . .pounds of water evaporated milligrams/liter . . . . . . . . . .1.0 . . . . . . . . . . . . . . .parts/million 

from and at 212°F milliters . . . . . . . . . . . . . ..001 . . . . . . . . . . . . . . . . . . . .liters 

22.75 . . . . . .pounds of water raised millimeters . . . . . . . . . . . . ..1 . . . . . . . . . . . . . . .centimeters 

from 62° to 212°F. 

.00328 . . . . . . . . . . . . . . . . . . . . .feet 

liters . . . . . . . . . . . . . . .1000 . . . . . . . . . . . . . . . . . .cu. cm. 

.0394 . . . . . . . . . . . . . . . . . . .inches 

.0353 . . . . . . . . . . . . . . . . . . . .cu. ft. 

.000001 . . . . . . . . . . . . . . . .kilometers 

61.02 . . . . . . . . . . . . . . . .cu. inches 

.001 . . . . . . . . . . . . . . . . . . .meters 

.001 . . . . . . . . . . . . . . . .cu. meters 

.000000621 . . . . . . . . . . . . . . . . . . . .miles 

.00131 . . . . . . . . . . . . . . . . .cu. yards 

.264 . . . . . . . . .gallons (U.S. liquid) 

2.113 . . . . . . . . . . .pints (U.S. liquid) 

1.057 . . . . . . . . . .quarts (U.S. liquid) 

liters/min. . . . . . . . . . ..00589 . . . . . . . . . . . . . . . .cu. ft./sec. 

.0044 . . . . . . . . . . . . . . . . .gals./sec. 

39.37 . . . . . . . . . . . . . . . . . . . . .mils 

.00109 . . . . . . . . . . . . . . . . . . . .yards 

mils . . . . . . . . . . . . . . ..00254 . . . . . . . . . . . . . . .centimeters 

.0000833 . . . . . . . . . . . . . . . . . . . . .feet 

.001 . . . . . . . . . . . . . . . . . . .inches 

66



minutes (angles) . . . . . ..0167 . . . . . . . . . . . . . . . . . .degrees 

.000185 . . . . . . . . . . . . . . . .quadrants 

.000291 . . . . . . . . . . . . . . . . . .radians 

60 . . . . . . . . . . . . . . . . .seconds 

minutes (time) . . . . ..0000992 . . . . . . . . . . . . . . . . . . .weeks 

.000694 . . . . . . . . . . . . . . . . . . . .days 

.0167 . . . . . . . . . . . . . . . . . . . .hours 

60 . . . . . . . . . . . . . . . . .seconds 

ounces . . . . . . . . . . . . .437.5 . . . . . . . . . . . . . . . . . . .grains 

28.35 . . . . . . . . . . . . . . . . . . .grains 

.0625 . . . . . . . . . . . . . . . . . .pounds 

.912 . . . . . . . . . . . . . .ounces (troy) 

ounces (fluid) . . . . . . . .1.805 . . . . . . . . . . . . . . . .cu. inches 

.0296 . . . . . . . . . . . . . . . . . . . .liters 

ounces (troy) . . . . . . . . . .480 . . . . . . . . . . . . . . . . . . .grains 

31.1 . . . . . . . . . . . . . . . . . . .grams 

1.097 . . . . . . . . . . . . .ounces (avdp.) 

ounce/sq. in. . . . . . . . . .4309 . . . . . . . . . . . . .dynes/sq. cm. 

.0625 . . . . . . . . . . . . .pounds/sq. in. 

1.732 . . . . . . . . . . . . . . .inches w.c. 

parts/million . . . . . . . . ..0584 . . . . . . . . . . . .grains/U.S. gal. 

.0702 . . . . . . . . . . . .grains/imp. gal. 

8.345 . . . . . . . . . .pounds/million gal. 

ppm (volume) . . .385,100,000 . . . . . . . . . . . . . . . . . . . . .lb/ft 3 

0.02404 . . . . . . . . . .micrograms/cu. m. 

ppm (weight) . . . . . . . . .0012 . . . . . . . . . .micrograms/cu. m. 

pints (liquid) . . . . . . . . .473.2 . . . . . . . . . . . . . . . .cubic cms. 

.0167 . . . . . . . . . . . . . . . . . .cubic ft. 

28.87 . . . . . . . . . . . . . .cubic inches 

.000473 . . . . . . . . . . . . . .cubic meters 

.000619 . . . . . . . . . . . . . . .cubic yards 

.125 . . . . . . . . . . . . . . . . . .gallons 

.473 . . . . . . . . . . . . . . . . . . . .liters 

.5 . . . . . . . . . . . . .quarts (liquid) 

poise 1.0 . . . . . . . . . . . . .gram/cm.-sec. 

pounds 7000 . . . . . . . . . . . . . . . . . . .grains 

453.6 . . . . . . . . . . . . . . . . . . .grams 

4.448 . . . . . .joules/meter (newtons) 

.454 . . . . . . . . . . . . . . . . .kilograms 

16 . . . . . . . . . . . . . . . . . .ounces 

14.58 . . . . . . . . . . . . . .ounces (troy) 

.0005 . . . . . . . . . . . . . . .tons (short) 

pounds of water . . . . . . ..016 . . . . . . . . . . . . . . . . . . . .cu. ft. 

27.68 . . . . . . . . . . . . . . . .cu. inches 

.12 . . . . . . . . . . . . . . . . . .gallons 

pounds of water/min. .000267 . . . . . . . . . . . . . . . . .cu. ft/sec. 

pounds/cu. ft. . . . . . . . . ..016 . . . . . . . . . . . . .grams/cu. cm. 

16.02 . . . . . . . . . . . . .kgs./cu. meter 

133,700 . . . . . . . . . . . . . .ppm (weight) 

.000579 . . . . . . . . . . . . .pounds/cu. in. 

pounds/cu. in. . . . . . . . .27.68 . . . . . . . . . . . . .grams/cu. cm. 

27680 . . . . . . . . . . . . .kgs./cu. meter 

1728 . . . . . . . . . . . . . .pounds/cu. ft 

pounds/ft. . . . . . . . . . . .1.488 . . . . . . . . . . . . . . . .kgs./meter 

pounds/in. . . . . . . . . . . .178.6 . . . . . . . . . . . . . . . .grams/cm. 

67 


pounds/sq. ft. . . . . . ..000473 . . . . . . . . . . . . . .atmospheres 

.016 . . . . . . . . . . . . . .feet of water 


.192 . . . . . . . . . . . .inches of water 

4.882 . . . . . . . . . . . . .kgs./sq. meter 

.111 . . . . . . . . . . . .ounces/sq. inch 

.00694 . . . . . . . . . . . .pounds/sq. inch 

pounds/sq. inc. . . . . . . . ..068 . . . . . . . . . . . . . .atmospheres 

2.307 . . . . . . . . . . . . . .feet of water 

2.036 . . . . . . . . . .inches of mercury 

27.71 . . . . . . . . . . . .inches of water 

703.1 . . . . . . . . . . . . .kgs./sq. meter 

16 . . . . . . . . . . . .ounces/sq. inch 

144 . . . . . . . . . . . .pounds/sq. foot 

quadrants (angle) . . . . . . .90 . . . . . . . . . . . . . . . . . .degrees 

5400 . . . . . . . . . . . . . . . . . .minutes 

1.571 . . . . . . . . . . . . . . . . . .radians 

324,000 . . . . . . . . . . . . . . . . .seconds 

quarts (liquid) . . . . . . . .946.4 . . . . . . . . . . . . . . . . . .cu. cms. 

.0334 . . . . . . . . . . . . . . . . . . . .cu. ft. 

57.75 . . . . . . . . . . . . . . . .cu. inches 

.000946 . . . . . . . . . . . . . . . .cu. meters 

.00124 . . . . . . . . . . . . . . . . .cu. yards 

.25 . . . . . . . . . . . . . . . . . .gallons 

.946 . . . . . . . . . . . . . . . . . . . .liters 

radians . . . . . . . . . . . . . .57.3 . . . . . . . . . . . . . . . . . .degrees 

3438 . . . . . . . . . . . . . . . . . .minutes 

.637 . . . . . . . . . . . . . . . .quadrants 

206,300 . . . . . . . . . . . . . . . . .seconds 

radian/sec. . . . . . . . . . . .9.55 . . . . . . . . . . . . . . . . . . . . .rpm 

rpm . . . . . . . . . . . . . . .0.1047 . . . . . . . . . . . . . . . . .rad./sec. 

seconds (angle) . . . ..000278 . . . . . . . . . . . . . . . . . .degrees 

.0167 . . . . . . . . . . . . . . . . . .minutes 

square centimeters . .197,300 . . . . . . . . . . . . . . .circular mils 

.00108 . . . . . . . . . . . . . . . . . .sq. feet 

.155 . . . . . . . . . . . . . . . .sq. inches 

.0001 . . . . . . . . . . . . . . . .sq. meters 

100 . . . . . . . . . . . . .sq. millimeters 

.00012 . . . . . . . . . . . . . . . . .sq. yards 

square feet . . . . . . . . . . .929 . . . . . . . . . . . . . . . . . .sq. cms. 

144 . . . . . . . . . . . . . . . .sq. inches 

.093 . . . . . . . . . . . . . . . .sq. meters 

.0000000359 . . . . . . . . . . . . . . . . .sq. miles 

92900 . . . . . . . . . . . . .sq. millimeters 

.111 . . . . . . . . . . . . . . . . .sq. yards 

square inches . . . . . . . .6.452 . . . . . . . . . . . . . . . . . .sq. cms. 

.00694 . . . . . . . . . . . . . . . . . . . .sq. ft. 

645.2 . . . . . . . . . . . . .sq. millimeters 

1,000,000 . . . . . . . . . . . . . . . . . .sq. mils 

.000772 . . . . . . . . . . . . . . . . .sq. yards 

square kilometers .10,760,000 . . . . . . . . . . . . . . . . . . . .sq. ft. 

1,000,000 . . . . . . . . . . . . . . . .sq. meters 

.386 . . . . . . . . . . . . . . . . .sq. miles



square meters . . . . . . .10000 . . . . . . . . . . . . . . . . . .sq. cms. 

10.76 . . . . . . . . . . . . . . . . . . . .sq. ft. 

1550 . . . . . . . . . . . . . . . .sq. inches 

1,000,000 . . . . . . . . . . . . .sq. millimeters 

1,196 . . . . . . . . . . . . . . . . .sq. yards 

square miles . . . .27,880,000 . . . . . . . . . . . . . . . . . . . .sq. ft. 

2.590 . . . . . . . . . . . . . . . . . .sq. kms. 

2,590,000 . . . . . . . . . . . . . . . .sq. meters 

3,098,000 . . . . . . . . . . . . . . . . .sq. yards 

square millimeters . . . . .1973 . . . . . . . . . . . . . . .circular mils 

.01 . . . . . . . . . . . . . . . . . .sq. cms. 

.0000108 . . . . . . . . . . . . . . . . . . . .sq. ft. 

.00155 . . . . . . . . . . . . . . . .sq. inches 

therms . . . . . . . . . . .100,000 . . . . . . . . . . . . . . . . . . . . . .btu 

tons (long) . . . . . . . . . . .1016 . . . . . . . . . . . . . . . . .kilograms 

2240 . . . . . . . . . . . . . . . . . .pounds 

1.12 . . . . . . . . . . . . . . .tons (short) 

tons (metric) . . . . . . . . .1000 . . . . . . . . . . . . . . . . .kilograms 

2205 . . . . . . . . . . . . . . . . . .pounds 

tons (short) . . . . . . . . . .907.2 . . . . . . . . . . . . . . . . .kilograms 

32000 . . . . . . . . . . . . . . . . . .ounces 

2917 . . . . . . . . . . . . . .ounces (troy) 

2000 . . . . . . . . . . . . . . . . . .pounds 

2430 . . . . . . . . . . . . . .pounds (troy) 

.893 . . . . . . . . . . . . . . . .tons (long) 

.908 . . . . . . . . . . . . . .tons (metric) 

68 


ton refrigeration (U.S.) .12,000 . . . . . . . . . . . . . . . . . . . .btu/hr 

83.33 . . . . . . . . . . . . . .lb. ice melted 

per hr. from and at 32°F 

watts . . . . . . . . . . . . . . .3.413 . . . . . . . . . . . . . . . . . . .btu/hr. 

.0569 . . . . . . . . . . . . . . . . . .btu/min. 

44.27 . . . . . . . . . . . . . . . .ft.-lbs./min. 

.738 . . . . . . . . . . . . . . . .ft.-lbs./sec. 

.00134 . . . . . . . . . . . . . . .horsepower 

.00136 . . . . . . . .horsepower (metric) 

.0143 . . . . . . . . . . .kg.-calories/min. 

.001 . . . . . . . . . . . . . . . . .kilowatts 

watt-hours . . . . . . . . . . .3.413 . . . . . . . . . . . . . . . . . . . . . .btu 

2656 . . . . . . . . . . . . . . . . . .foot-lbs. 

860.5 . . . . . . . . . . . . .gram-calories 

.00134 . . . . . . . . . .horsepower-hours 

.861 . . . . . . . . . . .kilogram-calories 

367.2 . . . . . . . . . . .kologram-meters 

.001 . . . . . . . . . . . . .kilowatt-hours 

watt/sq.cm. . . . . . . . . .3170.0 . . . . . . . . . . . . .btu/hr./sq. foot 

watt cm btu-ft 

sq. cm. °F . . . . . . . . . . .57.79 . . . . . . . . . . . . . . . hr. sq. ft. °F 

TEMPERATURE CONVERSIONS 

°Fahrenheit = 9/5°C + 32 

°Celsius = 5/9 (°F–32) 

°Rankine = °F absolute = °F + 459.69 

°Kelvin = °C absolute = °C + 273.16 

Fahrenheit to Celsius Celsius to Fahrenheit 

°F °C °F °C °C °F °C °F 

0 -17.78 950 510.0 0 32 850 1562 

20 -6.67 1000 537.8 10 50 900 1652 

40 4.44 1100 593.3 20 68 950 1742 

60 15.56 1200 648.9 30 86 1000 1832 

80 26.67 1300 704.4 40 104 1050 1922 

100 37.78 1400 760.0 50 122 1100 2012 

120 48.89 1500 815.6 60 140 1150 2102 

140 60.00 1600 871.1 70 158 1200 2192 

160 71.11 1700 926.7 80 176 1250 2282 

180 82.22 1800 982.2 90 194 1300 2372 

200 93.33 1900 1038 100 212 1350 2462 

250 121.1 2000 1093 150 302 1400 2552 

300 148.9 2100 1149 200 392 1450 2642 

350 176.7 2200 1204 250 482 1500 2732 

400 204.4 2300 1260 300 572 1550 2822 

450 232.2 2400 1316 350 662 1600 2912 

500 260.0 2500 1371 400 752 1650 3002 

550 287.8 2600 1427 450 842 1700 3092 

600 315.6 2700 1482 500 932 1750 3182 

650 343.3 2800 1538 550 1022 1800 3272 

700 371.1 2900 1593 600 1112 1850 3362 

750 398.9 3000 1649 650 1202 1900 3452 

800 426.7 3200 1760 700 1292 1950 3542 

850 454.4 3400 1871 750 1382 2000 3632 

900 482.2 3600 1982 800 1472 2050 3722

PRESSURE CONVERSIONS 

inches ounces/ inches kilograms/ millimeters kilowater 

sq in lb/sq in mercury millibars sq cm water pascals 

("w.c.) (osi) (psi) ("Hg) (mbar) (kg/cm 2 ) (mm H 2O) (kPa) 

.04 .023 .001 .003 .1 .0001 1 .01 

.1 .058 .004 .007 .25 .0003 2.54 .02 

.17 .1 .006 .013 .42 .0004 4.4 .04 

.2 .115 .007 .015 .5 .0005 5.08 .05 

.35 .2 .013 .026 .87 .0009 8.8 .09 

.39 .227 .014 .029 .97 .001 10 .1 

.40 .23 .015 .029 1 .0010 10.2 .1 

.5 .29 .018 .037 1.24 .0013 12.7 .12 

.787 .45 .028 .058 1.96 .002 20 .2 

.80 .46 .029 .059 2 .0020 20.4 .2 

.87 .5 .031 .064 2.16 .0022 22 .22 

1 .58 .036 .074 2.49 .0025 25.4 .25 

1.73 1 .063 .127 4.30 .0044 44 .43 

2 1.15 .072 .147 4.98 .0051 50.8 .5 

2.01 1.16 .073 .148 5 .0051 51 .5 

2.77 1.6 .1 .204 6.89 .0070 70.3 .69 

3 1.73 .108 .221 7.46 .0076 76.2 .75 

3.46 2 .125 .254 8.61 .0088 87.9 .86 

4 2.31 .144 .294 9.95 .010 101.6 1 

4.02 2.32 .145 .296 10 .010 102 1 

5 2.89 .181 .368 12.5 .013 127 1.25 

5.2 3 .188 .382 12.9 .013 131.9 1.29 

5.54 3.2 .2 .407 13.8 .014 140.7 1.38 

6 3.46 .216 .441 14.9 .015 152.4 1.49 

6.93 4 .25 .51 17.2 .018 175.8 1.72 

7 4.04 .253 .515 17.4 .018 177.8 1.74 

8 4.62 .289 .588 19.9 .020 203.2 1.99 

8.03 4.64 .29 .591 20 .020 204 2 

8.66 5 .313 .637 21.5 .022 219.8 2.15 

9 5.2 .325 .662 22.4 .023 228.6 2.24 

10 5.77 .361 .735 24.9 .025 254 2.49 

10.39 6 .375 .764 25.9 .026 263.8 2.59 

11 6.35 .397 .809 27.4 .028 279.4 2.74 

12 6.93 .433 .882 29.9 .030 304.8 2.99 

12.05 6.96 .435 .887 30 .031 306 3 

12.12 7 .438 .891 30.2 .031 307.7 3.02 

13 7.51 .469 .956 32.4 .033 330.2 3.24 

13.6 7.85 .491 1 33.8 .035 345.4 3.38 

13.86 8 .5 1.02 34.5 .035 351.6 3.45 

14 8.08 .505 1.03 34.9 .036 355.5 3.49 

15 8.66 .541 1.10 37.4 .038 381 3.74 

15.59 9 .563 1.15 38.8 .04 395.6 3.88 

16 9.24 .578 1.18 39.8 .041 406.4 3.98 

16.06 9.28 .58 1.18 40 .041 408 4 

17 9.82 .614 1.25 42.3 .043 431.8 4.23 

17.32 10 .625 1.27 43.1 .044 439.6 4.31 

18 10.39 .649 1.32 44.8 .046 457.2 4.48 

19 10.97 .686 1.4 47.3 .048 482.6 4.73 

19.05 11 .688 1.40 47.4 .048 483.6 4.74 

20 11.55 .722 1.47 49.8 .051 508 4.98 

69

PRESSURE CONVERSIONS (Cont’d) 




20.1 11.6 .725 1.48 50 .051 510 5 

20.78 12 .75 1.53 51.7 .053 528 5.17 

21 12.12 .758 1.54 52.3 .053 533 5.23 

22 12.7 .794 1.62 54.8 .056 559 5.48 

22.52 13 .813 1.66 56.0 .057 572 5.60 

23 13.28 .83 1.69 57.3 .058 584 5.73 

24 13.86 .866 1.76 59.7 .061 610 5.98 

24.1 13.92 .87 1.77 60 .061 612 6 

24.25 14 .875 1.78 60.3 .062 615 6.03 

25 14.43 .902 1.84 62.3 .064 635 6.23 

25.98 15 .938 1.91 64.6 .066 659 6.46 

26 15.01 .938 1.91 64.7 .066 660 6.47 

27 15.59 .974 1.99 67.2 .069 686 6.72 

27.2 15.7 .982 2 67.7 .069 711 6.77 

27.71 16 1 2.04 68.9 .070 703 6.89 

28 16.17 1.01 2.06 69.7 .071 711 6.97 

28.11 16.24 1.02 2.07 70 .071 714 7 

29 16.74 1.05 2.13 72.2 .074 737 7.22 

29.44 17 1.06 2.16 73.3 .075 747 7.33 

30 17.32 1.08 2.21 74.7 .076 762 7.47 

31 17.9 1.12 2.28 77.2 .079 787 7.72 

31.18 18 1.13 2.29 77.6 .079 791 7.76 

32 18.48 1.16 2.35 79.7 .081 813 7.97 

32.13 18.56 1.16 2.36 80 .082 816 8 

32.91 19 1.19 2.42 81.9 .084 835 8.19 

33 19.05 1.19 2.43 82.2 .084 838 8.22 

34 19.63 1.23 2.5 84.7 .086 864 8.47 

34-64 20 1.25 2.55 86.2 .088 879 8.62 

35 20.21 1.26 2.57 87.2 .089 889 8.72 

36 20.79 1.3 2.65 89.6 .091 914 8.96 

36.14 20.88 1.31 2.66 90 .092 918 9 

36.37 21 1.31 2.67 90.5 .092 923 9.05 

37 21.36 1.34 2.72 92.1 .094 940 9.21 

38 21.94 1.37 2.79 94.6 .097 965 9.46 

38.1 22 1.38 2.80 94.8 .097 967 9.48 

39 22.52 1.41 2.87 97.1 .099 991 9.71 

39.37 22.73 1.42 2.89 98.0 .1 1000 9.80 

39.84 23 1.44 2.93 99.1 .101 1011 9.91 

40 23.09 1.44 2.94 99.6 .102 1016 9.96 

40.16 23.20 1.45 2.96 100 .102 1020 10 

40.8 23.56 1.47 3 101.5 .104 1036 10.2 

41 23.67 1.48 3.01 102.0 .104 1041 10.2 

41.57 24 1.5 3.06 103.4 .106 1055 10.3 

42 24.25 1.52 3.09 104.5 .107 1067 10.5 

43 24.83 1.55 3.16 107 .109 1092 10.7 

43.3 25 1.56 3.18 107.7 .11 1099 10.8 

44 25.4 1.59 3.24 109.5 .112 1118 11 

45 26 1.63 3.31 112 .114 1144 11.2 

46 26.56 1.66 3.38 114.5 .117 1168 11.5 

46.76 27 1.69 3.44 116.3 .118 1184 11.6 

70

PRESSURE CONVERSIONS 




47 27.14 1.7 3.46 116.9 .119 1194 11.7 

48 27.71 1.73 3.53 119.4 .122 1219 12 

48.5 28 1.75 3.57 120.7 .123 1232 12.1 

49 28.29 1.77 3.60 121.9 .124 1245 12.2 

50 28.87 1.80 3.68 124.4 .127 1270 12.5 

50.23 29 1.81 3.69 125 .128 1276 12.5 

51 29.45 1.84 3.75 126.9 .13 1295 12.7 

51.96 30 1.88 3.82 129.3 .132 1320 12.9 

52 30.02 1.88 3.82 129.4 .132 1321 12.9 

53 30.6 1.91 3.9 131.9 .135 1346 13.2 

53.69 31 1.94 3.95 133.6 .136 1364 13.4 

54 31.18 1.95 3.97 134.4 .137 1372 13.4 

54.4 31.41 1.96 4 135.4 .138 1382 13.5 

55.4 32 2 4.07 137.8 .141 1408 13.8 

68 39.26 2.45 5 169.2 .173 1727 16.9 

78.7 45.46 2.84 5.79 195.8 .2 2000 19.6 

80.32 46.4 2.9 5.91 200 .204 2040 20 

81.6 47.11 2.94 6 203 .207 2072 20.3 

83.14 48 3 6.11 207 .211 2112 20.7 

95.2 55 3.44 7 237 .242 2418 23.7 

108.8 62.8 3.93 8 271 .276 2763 27.1 

110.8 64 4 8.15 276 .282 2816 27.6 

120.5 69.6 4.35 8.87 300 .306 3060 30 

138.6 80 5 10.2 345 .352 3517 34.5 

160.6 92.8 5.8 11.8 400 .408 4080 40 

166.3 96 6 12.2 414 .422 4223 41.4 

194 112 7 14.3 483 .493 4927 48.3 

196.9 113.7 7.1 14.5 490 .5 5000 49.0 

200.8 116 7.25 14.8 500 .510 5100 50 

221.7 128 8 16.3 552 .563 5631 55.2 

241 139 8.7 17.7 600 .612 6120 60 

249.4 144 9 18.3 621 .634 6335 62.1 

277.1 160 10 20.4 689 .703 7033 68.9 

281.1 162 10.15 20.7 700 .714 7140 70 

321.3 186 11.6 23.6 800 .816 8160 80 

361.4 209 13.05 26.6 900 .918 9180 90 

393.7 227 14.21 28.9 980 1 10,000 98.0 

401.6 232 14.5 29.6 1000 1.02 10,200 100 

415.7 240 15 30.6 1034 1.06 10,559 103.4 

554 320 20 40.7 1378 1.41 14,072 137.8 

693 400 25 51 1724 1.76 17,602 172.4 

831 480 30 61.1 2068 2.11 21,107 206.8 

970 560 35 71.3 2414 2.46 24,638 241.3 

1108 640 40 81.5 2757 2.81 28,143 275.8 

1386 800 50 101.9 3449 3.52 35,204 344.7 

1663 960 60 122.3 4138 4.22 42,240 413.7 

1940 1120 70 142.6 4827 4.93 49,276 482.6 

2217 1280 80 163.0 5516 5.63 56,312 551.6 

2494 1440 90 183.4 6206 6.33 63,348 620.5 

2771 1600 100 203.8 6895 7.04 70,383 689.5 

71

Abbreviations 

Air 

61 

effect of altitude 20 

effect of pressure 20 

effect of temp. 21 

infiltration 

pipe 

53 

sizing 16 

pressure losses 

Air Heating 

12 

heat requirements 

Alloys 

45 

thermal capacities 

Area 

40 

of circles 

Available Heat 

57, 58 

definition 35-36 

charts 51 

Black Body Radiation 

Blowers 

49 

as suction device 20 

fan laws 19 

horsepower 20 

ratings 

Boilers 

18, 19 

Btu/hr. & H.P. 31 

conversion factors 30 

sizing steam pipe 

Butane 

32 

butane/air mixtures 24 

properties 22, 23 

Cv Circles 

16 

areas 57, 58 

circumferences 

Circumference 

57, 58 

of circles 57, 58 

Coefficients of Discharge 4 

Cones, Pyrometric 

Conversions 

50 

boilers 30 

h.p. & Btu/hr. 31 

general 64 thru 68 

oil viscosity 26 

pressure 69 

temperature, °F & °C 

Crucibles 

69 

capacities & dimensions 

Drills 

43 

sizes 59 

tap drill sizes 60 

Duct Velocity 17 

Efficiency, Thermal 

Electrical 

36 

formulas 33 

motor current 34 

motor starters 33 

NEMA enclosures 34 

ohm’s law 33 

symbols 62, 63 

wire specs 

Equivalent Length 

33 

pipe 14 

valves 14 

Fan Laws 

Fans 

see blowers 

19 

INDEX 

Flame Tip Temp. 

Flow 

52 

and Cv 16 

and duct velocity 17 

orifices 4 

Flue Gas Analysis 52 

Flue Sizing 

Fume Incineration 

53 

heat requirements 45 

sizing 

Furnaces 

46 

cold air infiltration 53 

flue sizing 53 

thermal head 53 

turndown 36 

Gas/Air Mixtures 

Gases 

24 

available heat 51 

combustion products 23 

constituents 22 

density 22 

flame temp. 23 

flame velocity 22 

flammability limits 22 

heat release 23 

heating value 23 

ignition temp. 22 

mixtures 24 

pipe, sizing 16 

properties 22-24,37 

specific gravity 22 

specific volume 22 

stoichiometric ratio 

Heat 

22 

available 35-36 

balance 

losses 

35-36 

general 35-36 

refractory 44 

spray washers 48 

tank 47 

net output 35-36 

required for processes 41 

storage, refractory 44 

storage, tank 47 

transfer, equations 

Heating Operations 

52 

temp. & heat req’d. 

Liquid Heating 

41-42 

sizing, burner 

Metals 

47 

thermal capacities 

Motors 

40 

current 34 

formulas 33 

NEMA size starters 33 

Natural Gas, Properties 22-23 

Net Heat Output 

Nozzles 

35-36 

spray capacities 48 

Ohm’s Law 

Oil 

33 

ANSI specs 25 

heating value & °API 27 

piping pressure losses 27, 28 

piping temp. losses 29 

s.g. & °API 27 

typical properties 26 

viscosity conversions 26 

72 

Orifices 

capacities 

high pressure 9-11 

low pressure 5-8 

coefficients of discharge 4 

flow formulas 4 

Pipe 

capacities 54 

dimensions 

fittings 

54 

dimensions 55 

equivalent length 14 

flange templates 

pressure losses 

60 

air 12 

natural gas 13, 14 

oil 

sizing 

27, 28 

air, gas & mixture 15 

air, quick method 15 

branch 16 

steam 32 

water 31 

Pressure, Conversions 

Propane 

69-71 

propane/air mixtures 24 

properties 

see also Gases 

22, 23 

Pyrometric Cones 50 

Radiant Tubes 43 

Radiation, Black Body 49 

Refractory 

Sheet Metal 

44 

gauges 56 

weights 

Spray Washers 

56 

heat loss factors 48 

heat requirements 48 

nozzle capacities 

Steam 

48 

pipe sizing 32 

properties 30 

terminology 

Symbols 

30 

electrical 

Temperature 

62, 63 

°F & °C 68 

flame tip 52 

refractory face 44 

required, various processes 

Thermal 

41 

capacities, metals & alloys 40 

efficiency 36 

head, furnaces 53 

properties, materials 

Turndown 

37 

furnace 

Valves 

36 

Cv and flow 16 

equivalent pipe length 14 

Velocity, Duct 

Washers, spray 

17 

heat requirements 

Wire 

48 

gauges 56 

specifications 33 

weights 56

Tech Notes 

Section 1-Eclipse Equipment (numbers correspond to Bulletin numbers) 

656 Selecting TVT Mixing Tees (Page 74) 

810/812 Sizing Pilots, Blasts Tips & Pilot Mixers with Flow Charts (Page 76) 

Section 2-Engineering Data 

Part A- Combustion Data 

A-1 Flue Gas Analysis vs. Excess Air (Page 80) 

A-2 Flame Temperatures vs. Air Preheat & % Oxygen (Page 81) 

A-3 Available Heat vs. Oxygen Enrichment (Page 82) 

A-4 Available Heat-Extended Chart (Page 83) 

Part C- Control systems 

C-1 Summary of Fuel-Air Ratio Control Systems for Nozzle Mixing Burners (Page 84) 

C-2 Ratio Control Using Proportioning Fixed Port Valves for Nozzle Mixing Burners (Page 85) 

C-3 Ratio Control Using Proportioning (Adjustable Characteristic) Valves for Nozzle Mixing Burners (Page 87) 

C-4 Ratio Control Using Cross-Connected Proportionators for Nozzle Mixing Burners (Page 89) 

C-5 Ratio Control Using Cross-Connected Proportionator with Bleed Fitting for Nozzle Mixing Burners (Page 91) 

C-6 Ratio Control Using Electronic Controllers for Nozzle Mixing Burners (Page 92) 

C-7 Excess Air Operation by Controlling Fuel Only for Nozzle Mixing Burners (Page 94) 

C-8 Excess Air Operation with Biased Proportionator for Nozzle Mixing Burners (Page 95) 

C-9 Excess Air Operation with Throttled Impulse (Adjustable Bleed) to Proportionator for Nozzle Mixing 

Burners (Page 96) 

C-10 Backpressure Compensation System for Cross-Connected Nozzle Mix Burner Systems (Page 97) 

Part E- Emissions 

E-2 Conversion Factors for Emissions Calculations (Page 98) 

E-3 Correcting Emissions Readings to 3% O 2 or 11% O 2 Basis (Page 100) 

Part H- Heat Recovery 

H-1 Recuperator Efficiency: Fuel Savings & Effectiveness (Page 101) 

Part R- Regulations & Codes 

R-1 NFPA Requirements for Gas Burner Systems (Page 103) 

R-2 IRI Requirements for Gas Burner Systems (Page 105) 

Section 3-Application Data 

Part I- Incineration 

I-1 Heating Values of Flammable Liquids (Page 108) 

Part L- Liquid Heating 

L-1 Immersion Tube Sizing (Page 110) 

L-2 Submerged Combustion (Page 112) 

L-3 Immersion Tubes-What Will The Stack Temperature Be? (Page 116) 

Part O- Ovens 

O-1 Determining % O 2 in a Recirculating System (Page 117) 

73 

Table Of Contents

Tech Notes 

Selecting TVT Mixing Tees—Bulletin 656 

General Remarks: 

Selection Data Required: 

Selection Procedure: 

Series TVT two-valve mixing tees lack a tapered discharge sleeve, so they are not as 

efficient as LP Proportional Mixers. Their performance will also be strongly affected 

by downstream piping, so use them only where gas pressure available at the mixer 

connection exceeds mixture pressure by: 

3" w.c. for natural or LP gas (except 166-24-TVT, which requires 7" w.c.) 

6" w.c. for coke oven gas 

8" w.c. for digester gas 

For coke oven or digester gas, do not use the 84-16, 124-24 or 166-24; their gas inlets 

are too small. Also, do not use any of these mixers with producer gas. Producer gas 

flows far exceed the capacity of the gas orifices and inlet connections. 

1. CFH air flow through the mixer (if customer specifies Btu/hr, divide by 100 to 

get cfh air). 

2. Air pressure available at mixer inlet, "w.c. 

3. Mixture pressure desired, "w.c. 

Section I 

Sheet 656 

1. Refer to Table I, page 75. Select a mixer whose maximum air capacity is higher 

than the required air flow. 

2. To size the air jet, subtract the mixture pressure from the air pressure. This 

gives you the air pressure drop available across the mixer. Then refer to the 

graph. Locate the desired air flow on the horizontal axis and the air pressure 

drop on the vertical axis. Locate the point where they intersect and then move 

right to the next diagonal line. That line represents the optimum jet size. 

3. Cross-check the air jet size against Table I to be sure it is within the range of 

sizes available for the mixer. If it isn’t, select the next larger size of mixer to 

avoid taking a higher pressure drop. 

74

Air ∆P Through Mixer, "w.c. 

Table I - TVT Mixer Data 

Range of 

Mixer Maximum Jet Sizes 

Catalog Air Flow, Air Jet 1/32nds of Use Mixer With 

No. scfh Part No. an inch These Gases 

44-17-TVT 900 0217- 10 - 16 Natural, LP, Coke Oven, Digester 



84-16-TVT 3500 0225- 18 - 36 Natural, LP 


124-24-TVT 8000 0695- 32 - 56 Natural, LP 


166-24-TVT 15,000 0994- 36 - 80 Natural, LP 

168-30-TVT 15,000 0994- 36 - 80 Natural, LP, Coke Oven, Digester 

Figure I - Air Jet Sizing Chart 

Air Jet Size 

21 23 25 27 29 31 33 35 37 39 42 46 50 54 

10 11 12 13 14 15 16 17 18 19 20 22 24 26 28 30 32 34 36 38 40 44 48 52 56 

30 

25 

58 

60 

20 

62 

64 

15 

66 

68 

70 

72 

10 

74 

9 

76 

8 

78 

7 

6 

80 

200 300 400 500 600 800 1000 1500 2000 3000 4000 5000 6000 8000 10,000 15,000 

Maximum 

For 44-17 TVT 

Maximum 

For 64-16 

& 66-24 TVT 

Max. For 

84-16 & 

86-24 TVT 

Air Flow Through Mixer, scfh 

75 

Maximum For 

124-24 & 

126-24 TVT 

Max. For 

166-24 & 

168-30 TVT

Tech Notes 

Sizing Pilots, Blast Tips & Pilot Mixers With Flow Charts 

Selection Factors 

Using The Charts Properly 

Air 

To select the right equipment, you need to know: 

1. Type and number of pilot or blast tips; 

2. Btu/hr. at which each tip will fire; 

3. Air pressure (P ) available at the mixer inlet. 

A 

1. From the tip capacity chart on page 77, find the required 

mixture pressure. Do not exceed 8" w.c. mixture pressure, 

unless you’ve chosen a Cumapart (CP) tip or blast tip. 

P A 

P M 

P P 

A- M = Mixture P 

Section I 

Sheet 810/812 

Desired Btu/hr. 

2. Subtract the mixture pressure (P M ) found in Step 1 from the air pressure 

(P A ) which is available at the mixer. The difference is the mixer 

pressure drop. 

3. Figure the total air flow through the mixer by the following equation: 

Btu/hr. per tip x number of tips 

cfh air = 100 

4. Next, refer to the mixer air capacity charts (page 78 for Series 121 mixers 

and page 79 for Series 131). To use the charts properly, follow the 

directions below: 

1 Locate the mixer 

pressure drop figure 

in Step 2, and read 

to the right. 

5. Do not use the Series 121 mixers above 300 scfh air or the Series 131 

mixers above 600 scfh air—otherwise pipe velocities are too high. 

76 

Pressure Drop 

Mixture Pressure 

ABC (1234) 

Air Flow 

2 Locate the air flow figured in Step 3 

and read up. 

3 

XXX 

Desired Tip 

YYY 

ZZZ 

From the point where 

these lines cross, move 

right to the nearest mixer 

flow curve. This curve is 

the proper size mixer to use. 

The air jet part number 

is in parentheses.

Mixture Pressure, "w.c. 

8 

6 

5 

4 

3 

2 

1 

1 2 3 4 5 6 

1-K 

Capacities Of Eclipse Pilot & Blast Tips 

2-K 

1CP 

77 

1F 

3-K 

4-K 

2CP 

20-ST 

10 20 30 40 50 60 100 

Btu/hr. x 1000 @ 10:1 Air/Gas Ratio 

5-K 

3RAFI 

2-N 

2F 

3RAF 

6-K 

3CP 

3EP 

4RAFI 

3F 

4RAF 

4EP 

4F 

5RAFI 

5RAF

ΔP P Across Mixer, "w.c. 

50 

40 

30 

20 

10 

6 

5 

4 

3 

2 

Series 121 Pilot Mixers 

Air Flow Capacity 

Mixer Catalog No. & 

(Air Jet Part No.) 

121-46 (14520-1) 

1 

10 15 20 30 40 50 60 80 100 150 200 300 

Combustion Air Flow Through Mixer, SCFH 

(Btu/hr. = SCFH Air x 100) 

78 

121-42 (14520-2) 

121-40 (14520-17) 

121-36 (14520-3) 

121-30 (14520-16) 

121-25 (14520-5) 

121-22 (14520-6) 

121-18 (14520-7) 

121-17 (14520-15) 

121-12 (14520-8) 

121-10 (14520-14) 

121-8 (14520-13) 

121-6 (14520-12) 

121-4 (14520-11) 

121-7/32 (14520-9) 

121-1 (14520-10)

ΔP P Across Mixer, "w.c. 

50 

40 

30 

20 

10 

6 

5 

4 

3 

2 

1 

20 30 40 50 60 

Series 131 Pilot Mixers 

Air Flow Capacity 

Mixer Catalog No. & 

(Air Jet Part No.) 

131-4 (10254-1) 

80 100 150 200 300 

Combustion Air Flow Through Mixer, SCFH 

(Btu/hr. = SCFH Air x 100) 

79 

131-5 (10254-2) 

131-6 (10254-3) 

131-11/64 (10254-14) 

131-13/64 (10254-8) 

400 500 600 

131-7 (10254-4) 

131-15/64 (10254-9) 

131-8 (10254-5) 

131-17/64 (10254-10) 

131-9 (10254-6) 

131-19/64 (10254-11) 

131-10 (10254-7) 

131-21/64 (10254-15)

Tech Notes 

Flue Gas Analysis vs. Excess Air 

Reference: 

Figure 1: 

Flue Gas Constituents 

vs. % Excess Air 

Eclipse Combustion Engineering Guide, p. 52 

Section 2 

Sheet A-1 

The graph below supplements the flue gas analysis chart on page 52 of the 

Combustion Engineering Guide, which extends to only 200% excess air. 

These curves are calculated for Birmingham Natural Gas, same as the 

Engineering Guide. 

% Flue Gas Constituent By Volume 

20 

15 

10 

5 

% Oxygen—Dry Sample 

% Oxygen—Saturated Sample 

% Carbon Dioxide—Natural Gas 

0 

200 400 600 800 1000 1200 1400 1600 1800 2000 

80 

% Excess Air

Tech Notes 

Flame Temperatures vs. Air Preheat & % Oxygen 


Figure 1: 

Theoretical Flame 

Temperature vs. Preheat 

Figure 2: 

Theoretical Flame 

Temperature vs. O 2 in Air 

Section 2 

Sheet A-2 

Both preheated air and oxygen enrichment increase the theoretical temperature 

of burner flames. The following graphs show their effect on the 

theoretical flame temperature of natural gas, which, with 60°F combustion 

air and 21% oxygen, would be about 3500 - 3550° F. 

Theoretical Flame Temp., °F 

Flame Temperature, °F 

4500 

4000 

3500 

0 

5200 

4800 

4400 

4000 

3600 

200 400 600 800 1000 1200 1400 1600 

Combustion Air Temperature, °F 

20 40 60 80 100 

81 

% Oxygen In Air

Tech Notes 

Available Heat vs. Oxygen Enrichment 

Section 2 

Sheet A-3 

General Remarks: The graph below shows available heat as a function of flue gas temperature 

and percent oxygen in the combustion air stream. These curves were calculated 

for natural gas with combustion air at 60°F. 

Figure 1: 

Available Heat vs. 

Oxygen Enrichment 

% Available Heat 

100 

80 

60 

40 

20 

0 

2000 

2200 

82 

2400 

2600 

Flue Gas Temperature, °F 

2800 

3000 

100% O 2 

35% O 2 

25% O 2 

20.9% O 2

Tech Notes 

Available Heat—Extended Chart 

Reference: 

Figure 1: 

Available Heat vs. Flue 

Gas Exit Temperature, °F 


Section 2 

Sheet A-4 

Page 51 of the Eclipse Combustion Engineering Guide carries two available 

heat charts, but unfortunately, the more useful one of the two doesn’t cover 

flue gas temperatures below 1000°F. The chart below, calculated from the 

same conditions as the Engineering guide chart, extends these curves down 

to 300°F flue gas temperature. 


100 

90 

80 

70 

60 

50 

40 

30 

20 

10 

350% 

400% 

500% 

600% 

800% 

1000% 

1200% 

Based On Birmingham Natural Gas (1002 Btu/Cu. ft., 0.6 Sp. Gr.) 

0% 

10% 

0 

0 200 600 1000 1400 1800 2200 2600 3000 

83 

250% 

300% 

200% 

150% 

% Excess Air 

100% 

Flue Gas Exit Temperature, °F 

50% 

25%

Tech Notes 

Summary of Fuel-Air Ratio Control Systems 

for Nozzle Mixing Burners 

Control System 

System 

Cost* 

Required 

Gas 

Pressure** 

Control Mode 

Hi-Low Modulating Firing Rate? 

* I=Inexpensive, M= Moderate, E=Expensive 

** L= Low, M=Moderate, H= High 

*** Depends on air and gas pressures at burner. See sheets for individual systems. 

† If bleeder vent is connected to combustion chamber. 

If backpressure 

fluctuates, does system 

maintain constant: 

Fuel-Air 

Ratio? 

On multiple burner 

zones, if one is 

shut off, do the 

others hold their 

ratio? 

On-ratio, linked valve 

On-ratio, 

I L • No *** No 

characterized valve 

On-ratio, cross connected 

M L to M • • No *** No 

proportionator 

On-ratio, cross connected 

M H • • No Yes Yes 

proportionator & bleeder M L to M • • No Yes Yes 

On-ratio, electronic 

Excess air, 

E M • • Yes Yes No 

fuel-only control 

Excess air, 

I M • • No *** No 

biased proportionator 

Excess air, 

M H • • No No Yes 

throttled impulse M H • • No Yes† Yes 

84 

Section 2 

Sheet C-1

Tech Notes 

Nozzle Mixing Burners 

Ratio Control Using Proportioning (Linked) Fixed Port Valves 

FUEL 

(continued on page 86) 

2 

1 

Section 2 

Sheet C-2 

Operating Principle Air and gas passages in the burner are the fixed resistances in the system. 

Control valves in the air and gas lines are the variable resistance. The two 

valves are connected by linkages to a common drive motor so that, in theory, 

they open and close in proportion, maintaining a fixed air-gas ratio over 

the system’s turndown range. 

Advantages 

• Valve operation can be readily understood—confidence builder for persons 

unfamiliar with control systems. 

• Working parts are visible—little chance that a hidden defect is present. 

• Can be used with low gas supply pressures. If a large enough gas valve is 

selected, the pressure required is only a little higher than the burner gas 

nozzle pressure (2 in above figure). 

• Inexpensive. 

85

Disadvantages 

• Differences in valve characteristic curves make it difficult or impossible 

to hold a fixed gas-air ratio across the entire turndown range. The system 

is best limited to high-low control. 

• Unless air and gas pressures at the burner (1 and 2 in the figure on page 

85) are equal, unforeseen changes in combustion chamber pressure will 

cause the burner to shift off-ratio according to the table below: 

If Air Pressure Is 

Goes More 

Positive (+), Then: 

And Chamber Pressure 

Stays The 

Same (o), Then: 

Goes More 

Negative (-), Then: 

Higher than gas pressure Burner goes leaner No change Burner goes richer 

Same as gas pressure No change No change No change 

Lower than gas pressure Burner goes richer No change Burner goes leaner 

If air pressure at the burner is higher than the gas pressure (this is usually 

the case), they can be made equal by installing a limiting orifice valve 

between the gas control valve and burner and adjusting it until pressure 

(2) equals pressure (1). However, this negates one of the advantages of 

linked valve systems—the low gas pressure requirement. 

• If the air supply becomes starved due to a dirty blower wheel or a plugged 

filter, the system will go rich. The gas valve responds only to the mechanical 

linkage, not to air flow changes. 

• If multiple burners are controlled by a single set of linked valves, and the 

fuel flow to one burner is throttled back manually or shut off entirely, 

that fuel will go to the other burners, forcing them to run rich. In addition 

to the safety hazard this presents, it makes multiple burners tedious to 

set up. Any gas adjustment made to one burner upsets the settings of the 

other burners in the zone. 

86

Tech Notes 


Ratio Control Using Proportioning (Adjustable Characteristic) Valves 

Section 2 

Sheet C-3 

Operating Principle Air and gas passages in the burner are the fixed resistances in the system. 

Control valves are the variable resistances and are connected in tandem to 

a common drive motor. Because it is practically impossible to get two fixed 

port valves to track together over their turndown range, at least one of the 

valves is fitted with an adjustable screw rack which makes the valve open 

faster or slower than the linkage calls for. This permits the valve’s flow 

curve to be adjusted to more closely match that of the fixed port valve. 

Advantages 

Disadvantages 

• Valve operation can be readily understood—confidence builder for persons 

unfamiliar with control systems. 

• Working parts are visible—little chance that a hidden defect is present. 

• Can be used with low gas supply pressures. 

• Can be used with proportioning or high-low control systems. 

• Adjustable characteristic valves are usually expensive. 

• Time consuming to set up. Most screw racks contain 8 to 12 adjustment 

points, which must be individually set when the burner is commissioned. 

• Unless air and gas pressures at the burner (1 and 2 in the figure below) 

are equal, unforeseen changes in combustion chamber pressure will cause 

the burner to shift off-ratio according to the table on page 88. 

FUEL 

87 

2 

1

Disadvantages (continued) 

If Air Pressure Is 

Goes More 

Positive (+), Then: 

And Chamber Pressure 

Stays The 

Same (o), Then: 

Goes More 

Negative (-), Then: 

Higher than gas pressure Burner goes leaner No change Burner goes richer 

Same as gas pressure No change No change No change 

Lower than gas pressure Burner goes richer No change Burner goes leaner 

If air pressure at the burner is higher than the gas pressure (this is usually 

the case), they can be made equal by installing a limiting orifice valve 

between the gas control valve and burner and adjusting it until pressure 

(2) equals pressure (1). However, this negates one of the advantages of 

linked valve systems—the low gas pressure requirement. 

• If the air supply becomes starved due to a dirty blower wheel or a plugged 

filter, the system will go rich. The gas valve responds only to the mechanical 

linkage, not to air flow changes. 

• If multiple burners are controlled by a single set of linked valves, and the 

fuel flow to one burner is throttled back manually or shut off entirely, 

that fuel will go to the other burners, forcing them to run rich. In addition 

to the safety hazard this presents, it makes multiple burners tedious to 

set up. Any gas adjustment made to one burner upsets the settings of the 

other burners in the zone. 

88

Tech Notes 


Ratio Control Using Cross-Connected Proportionators 

Section 2 

Sheet C-4 

Operating Principle Burner air passage is fixed resistance for air flow. Gas passages in the 

burner are usually too large to serve as the fixed resistance, so a limiting 

orifice valve is installed at the gas inlet . At setup, this valve is adjusted to 

provide the correct gas flow when gas pressure (2) is equal to air pressure 

(1). Low fire gas-air ratio is set with spring in Proportionator. 

Advantages 

FUEL 

• Easy to set up. Once high and low fire ratios are set, everything in between 

is taken care of. 

• Can be used with proportioning or high-low control systems. 

• No problem with mismatched valve flow curves. Proportionator is slave to 

air valve and automatically matches its characteristic curve. 

• Fuel-air ratio is unaffected by unforeseen changes in combustion chamber 

pressure. 

• Although air starvation due to a plugged filter or dirty blower wheel will 

cause a loss in firing capacity, it will not cause the system to go rich. The 

proportionator automatically reduces fuel flow as the air flow drops off. 

• On multiple burner systems fed from a single air control valve and 

proportionator, changing or shutting off the fuel flow to one burner will 

not upset the fuel flow to the others. This makes initial setup easier and 

eliminates the hazard of burners in a zone going rich because one of 

them has been misadjusted or shut off. 

• If proportionator permits, this system can be converted to an excess air 

system (see page 95) with a simple proportionator spring adjustment. 

89 

3 

Cross 

Connection 

Proportionator Limiting 

Orifice 

2 

1

Disadvantages 

• Requires higher gas pressures. Gas pressure at (3) in the figure on page 

89 must equal air pressure at (1) plus gas pressure drop through 

proportionator valve. 

• Operating principles of proportionator are poorly understood, especially 

in oven and air heating industry; operators don’t know how to set up 

systems. 

• Internal working of proportionator can’t be seen. Operators don’t know if 

it’s working correctly and, as a result, are afraid of it. 

90

Tech Notes 

Section 2 

Sheet C-5 


Ratio Control Using Cross-Connected Proportionator With Bleed Fitting 

Operating Principle Used where proportionator system is desired, but where gas pressure at (3) 

is insufficient to make a conventional proportionator system work (see page 

89). This set-up is also used where the loading pressure on the proportionator 

is equal to or higher than the maximum inlet gas pressure the proportionator 

can tolerate. An adjustable bleed fitting—basically a needle valve in a tee— 

reduces the loading pressure (4) on the proportionator to a pressure at 

least 2" w.c. lower than the inlet gas pressure (3). This permits the 

proportionator to respond to changes in air loading pressure (1) over the 

entire turndown range. 

Advantages 

Disadvantages 

FUEL 

Bleed Fitting 

3 

Cross 

Connection 


Orifice 

4 

If, for example, high fire air pressure (1) is 20" w.c., but gas supply (3) is 

only 13" w.c., the bleeder could be set to bleed off 50% of the air loading 

pressure, producing a pressure of 10" w.c. at (4) and (2). 

Same as the conventional proportionator system (see page 89), except that 

combustion chamber pressure fluctuations will cause the system to go offratio. 

Can be compensated by connecting the vent of the bleed fitting to the 

combustion chamber. 

• Same as the conventional proportionator system (see page 89), except 

that high inlet gas pressure is no longer required. 

• Bleed fittings contain small orifices which are susceptible to plugging by 

dirt. Filtered combustion air will alleviate the problem, but bleeders will 

always require frequent maintenance attention and they are subject to 

unauthorized tampering. 

91 

2 

1

Tech Notes 


Ratio Control Using Electronic Controllers 

Section 2 

Sheet C-6 

Operating Principle For all of its sophistication, a variation of the linked valve system. In this 

case, the linkage is electronic instead of mechanical. This system is also 

known as a “mass flow” control system, although this a misnomer—the 

flow signals fed to the controller are related either to pressure differential 

or to flow velocity. 

Advantages 

FUEL 

Air Flow 

Meter 

Fuel Flow 

Meter 

Cross 

Connection 

Primary 

Valve 

Electronic 

Controller 

Slave Valve 

The air and fuel lines each contain a motor-driven control valve and a flow 

metering device (orifice plate & ΔP transmitter, turbine meter, vortex-shedding 

flowmeter, etc.) One of the control valves is the primary valve, driven 

by the temperature controller. The second valve is slaved to the first through 

the electronic ratio controller. 

Flow meters in the air and fuel lines feed signals proportional to flow to the 

controller. The controller compares the signals and, if they are out of ratio, 

sends a correcting signal to the slave valve, which then alters its flow to 

restore the desired air-fuel ratio. 

• Extremely high accuracy inherent to electronic systems. 

• Can be integrated with master computer to control burner, as well as 

provide fuel consumption data. 

• If controller can be reprogrammed, can be reconfigured as an excess air 

system. 

• Will not allow the burner to go rich if air starvation occurs. 

• Provided that air and fuel supply pressures are adequate, will maintain a 

predetermined firing rate regardless of combustion chamber backpressure 

fluctuations. This is the only system that will do so. 

92 

TC

Disadvantages 

• Most expensive of all the ratio control systems. 

• No matter how sophisticated the electronics, the accuracy of the system 

is no better than the flow-sensing elements. If orifice plates are used to 

measure flows, accuracy degrades rapidly at turndown ratios greater than 

4:1 unless systems are individually calibrated in the field. 

• On a multiple burner system, turning the fuel of one burner down or off 

will cause the others to run rich—this system will try to maintain a gas 

flow proportional to airflow, regardless of where the gas has to go. 

93

Tech Notes 


Excess Air Operation By Controlling Fuel Only 

FUEL 

Optional Manual 

Trimming Valve 

Section 2 

Sheet C-7 

Operating Principle This system is known as the “fuel only control”, “fixed air” or “wild air” 

system; it is the simplest of all excess air systems. A motor-driven valve is 

placed in the fuel line, while the air has no flow controller—a manual 

trimming valve might be installed for servicing or limiting the high fire 

flow. 

Advantages 

Disadvantage 

• Low cost. 

• Permits attainment of the maximum excess air capability of the burner. 

• Suitable for high-low or proportioning control. 

• If multiple burners are controlled from a single fuel valve, reducing or 

shutting off the fuel flow to one of them causes the others to go richer. 

94

Tech Notes 


Excess Air Operation With Biased Proportionator 

Section 2 

Sheet C-8 

Operating Principle System installation is identical to conventional proportionator system 

(see page 89), but requires a proportionator whose spring can be adjusted 

to produce a significant negative bias. System is customarily set 

up to operate near stoichiometric ratio at high fire. As air valve closes, 

the proportionator—with its negative spring bias—causes fuel flow to 

decrease even more rapidly, producing increasing amounts of excess 

air. 

Advantages 

Disadvantages 

FUEL 

3 

Cross 

Connection 


Orifice 

• Better fuel economy than fuel-only control excess air system (see page 

94). 

• Suitable for high-low or proportioning control. 

• Unlike fuel-only control system, turning down or shutting off the gas 

flow to one burner in a multi-burner system will not cause the others 

to go rich. 

• Not capable of excess air rates as high as the fuel-only control system. 

• More expensive than fuel-only control system. 

95 

2 

1

Tech Notes 


Excess Air Operation With Throttled Impulse (Adjustable Bleed) To 

Proportionator 

Section 2 

Sheet C-9 

Operating Principle A variation on the cross-connected proportionator system (see page 89). 

There is no control valve in the combustion air line. Instead, the firing rate 

control valve is placed in the bleed leg of a tee in the impulse line to the 

proportionator, and the linkage is adjusted to make the bleed valve reverse-acting; 

i.e., the valve closes when the temperature controller calls 

for heat. The limiting orifice or needle valve in the loading line is closed 

partway to restrict air flow through the impulse line—this insures that the 

motor-driven bleed valve is able to control over its entire range. 

Advantage 

Disadvantages 

FUEL 

Cross 

Connection 

Small Limiting Orifice 

Or Needle Valve 

Tee 

Optional Manual 

Trimming Valve 


Orifice 

Motor-Driven 

Bleed Valve 

• Of all the excess air control systems, this one probably has the best 

combination of sensitivity and a wide operating range. 

• Like fixed bleed orifice sytems, this control system can be upset by accumulations 

of airborne dirtand unauthorized tampering. 

• The only valve proven suitable as a motor-driven bleed valve is the North 

American 3/8" Adjustable Port Valve. Even 3/8" motorized oil valves— 

whether Eclipse’s, Hauck’s or North American’s—lack the sensitivity for 

this application. 

96

Tech Notes 

Backpressure Compensation System 

For Cross-Connected Nozzle Mix Burner Systems 

Purpose: 

Method: 

Example: 

To maintain a constant burner firing rate and fuel-air ratio regardless of 

random fluctuations in combustion chamber backpressure. 

Hold a constant differential pressure between point “B” (upstream of main 

air control valve) and point “D” (combustion chamber), even if pressure at 

point “D” varies. This is done by putting two air control valves in series, one 

responding to the temperature controller, the other to the differential pressure 

between points “B” and “D”. 

Blower 

Power 

Supply 

Pressure 

Controller 

A 

ΔP Transducer 

PC 

Assume backpressure will vary uncontrollably between 0 & 10" w.c. 

Assume burner ΔP is 10" w.c. @ high fire, 1" w.c. @ low fire. 

Main air control valve ΔP is 5" w.c. @ high fire. 

Blower develops 30" w.c. static pressure. 

B 

Section 2 

Sheet C-10 

Static Pressures, Differential Pressures, Must Be 

Firing Back "W.C. "W.C. Constant 

Rate Press A B C D A-B B-C C-D A-C A-D B-D 

0" w.c. 30 15 10 0 15 5 10 20 30 15 

High 5" w.c. 30 20 15 5 10 5 10 15 25 15 

10" w.c. 30 25 20 10 5 5 10 10 20 15 

0" w.c. 30 15 1 0 15 14 1 29 30 15 

Low 5" w.c. 30 20 6 5 10 14 1 24 25 15 

10" w.c. 30 25 11 10 5 14 1 19 20 15 

97 

Motorized 

Trim Valve 

TC 

Main Air 

Control Valve 

Chamber Pressure Impulse Line 

Temperature 

Controller 

C 

ABP ALO 

D

Tech Notes 

Conversion Factors For Emissions Calculations 

Preparing emissions estimates for environmental authorities can be difficult 

because they often ask for emissions expressed in units not available 

through existing data. Here are the conversion procedures for some 

of the more commonly-used measurement systems: 

1) ppm at 3% O (15% excess air) in dry flue gases to lb./million Btu 

2 

(ppm)(F3) = lb./million Btu 

Values of multiplier F3 for various fuels and emissions 

NOX Aldehydes, Unburned Hydrocarbons, 

Measured Measured As Measured As: 

Various Fuels As NO2 CO Formaldehyde Methane Propane CO2 SO2 

Birmingham Nat. Gas* .001187 .000722 .000781 .000416 .001147 .001147 .001672 

Propane .001185 .000721 .000780 .000415 .001146 .001146 .001669 

Butane .001212 .000735 .000798 .000424 .001172 .001172 .001707 

#2 Oil** .001317 .000801 .000867 .000461 .001273 .001273 .001854 

2) lb./million Btu to ppm at 3% O (15% excess air) in dry flue 

2 

gases 

(lb./million Btu)(f3) = ppm @ 3% O2, dry 

Values of multiplier f3 for various fuels and emissions 




Birmingham Nat. Gas* 842 1385 1280 2404 872 872 598 

Propane 844 1387 1282 2410 873 873 599 

Butane 825 1361 1253 2358 853 853 586 

#2 Oil** 759 1248 1153 2169 786 786 539 

3) ppm at 0% O in dry flue gases to lb./million Btu 

2 

(ppm)(F0) = lb./million Btu 

Values of multiplier F0 for various fuels and emissions 




Birmingham Nat. Gas* .001017 .000617 .00067 .000356 .000983 .000983 .001432 

Propane .001018 .000619 .00067 .000356 .000984 .000984 .001434 

Butane .001042 .000634 .000686 .000365 .001007 .001007 .001468 

#2 Oil** .001133 .00069 .000746 .000397 .001096 .001096 .001596 

* 1002 Gross Btu/cubic foot, 8.48 Cubic feet dry flue products at stoichiometric ratio. 

** Calculated as heptadecane, C 17 H 36 , 19,270 Gross Btu/lb. 

98 


Section 2 

Sheet E-2

4) lb./million Btu to ppm at 0% O2 in dry flue gases 

(lb./million Btu)(f0) = ppm @ 0% O2, dry 

Values of multiplier f0 for various fuels and emissions 




Birmingham Nat. Gas* 983 1621 1493 2809 1017 1017 698 

Propane 982 1616 1493 2809 1016 1016 697 

Butane 960 1577 1458 2740 983 983 681 

#2 Oil** 883 1449 1340 2519 912 912 627 

5) ppm at 3% O or 0% O in dry flue gases to lb./year 

2 2 

First, calculate lb./million Btu with Step 1 or 3 on the first page. 

Then convert to lbs./year with the following relationship: 

(lb./million Btu) (Maximum Burner Input, million Btu/hr.) (operating 

hrs./year) = lb./year 

6) lb/year to ppm at 3% O or 0% O in dry flue gases 

2 2 

lb./year ÷ operating hrs./year ÷ Maximum Burner Input, million 

Btu/hr. = lb./million Btu 

Convert lb./million Btu to ppm with Step 2 or 4. 

7) ppm at 3% O 2 or 0% O 2 in dry flue gases to gm/Nm 3 

(ppm)(G) = gm/Nm 3 

Values of multiplier G for various emissions 



Emission As NO 2 CO Formaldehyde Methane Propane CO2 SO2 

G .002031 .001235 .001341 .000716 .001969 .001965 .002861 

8) gm/Nm3 to ppm at 3% O or 0% O in dry flue gases 

2 2 

(gm/Nm3 )(g) = ppm 

Values of multiplier g for various emissions 



Emission As NO2 CO Formaldehyde Methane Propane CO2 SO2 

g 492.4 809.7 745.7 1396.6 507.9 508.9 349.5 

* 1002 Gross Btu/cubic foot, 8.48 Cubic feet dry flue products at stoichiometric ratio. 

** Calculated as heptadecane, C 17 H 36 , 19,270 Gross Btu/lb. 

99

Tech Notes 

Section 2 

Sheet E-3 

Correcting Emissions Readings to 3% O 2 or 11% O 2 Basis 

Many environmental authorities, including 

the U.S. EPA and several European agencies, 

require that gaseous pollutants, like 

NO and CO, be reported in ppm (parts per 

x 

million by volume) corrected to a based of 

3% excess O —or 15% excess air—in the flue 

2 

gases. Japan, on the other hand, customarily 

uses a base of 11% O . 2 

Emission readings taken at different oxygen 

levels can be easily converted to a standard 

base using a multiplier: 

ppm = ppm x multiplier 

corrected test 

The multiplier is calculated from the oxygen 

reading taken during the test and the 

base oxygen reading required by the regulation: 

21 - % O base 

2 

multiplier = 

21 - % O test 2 

For your convenience, a table of multipliers 

is presented to the right. 

100 

Multiplier For: 

%O2 3%O2 11%O2 0 .86 .48 

1 .9 .5 

2 .95 .53 

3 1 .56 

4 1.06 .59 

5 1.13 .63 

6 1.2 .67 

7 1.29 .71 

8 1.38 .77 

9 1.5 .83 

10 1.64 .91 

11 1.8 1 

12 2.0 1.11 

13 2.25 1.25 

14 2.57 1.43 

15 3.0 1.67 

16 3.6 2 

17 4.5 2.5 

18 6 3.33 

18.5 7.2 4 

19 9 5 

19.5 12 6.67 

20 18 10 

20.2 22.5 12.5 

20.4 30 16.67 

20.6 45 25 

20.8 90 50

Tech Notes 

Recuperator Efficiency: Fuel Savings & Effectiveness 

Percent Fuel Savings 

Percent Effectiveness 

Section 2 

Sheet H-1 

There are two commonly-used methods for figuring recuperator efficiency: 

percent fuel savings and percent effectiveness. 

Percent savings is calculated by this relationship: 

( ) 

% Available Heat Less Recuperator 

% Savings= x100 

% Available Heat With Recuperator 

Because available heat figures vary with the composition of the fuel and 

the amount of excess air, one supplier’s fuel savings data may be different 

from another’s by one or two percentage points. More often than not, the 

tables will be based on natural gas at 10% excess air. 

Percent effectiveness measures the inherent heat transfer capabilities of 

the recuperator without regard to fuel composition or fuel/air ratio: 

( 

Combustion Air Temp Combustion Air Temp 

) 

Flue Gas Temp 

Entering Exchanger Entering Exchanger 

Leaving Exchanger - Entering Exchanger 

% Effectiveness= x100 

Combustion Air Temp 

- 

Basically, it compares the actual rise in combustion air temperature to the 

maximum that could possibly be achieved (combustion air preheated to 

the same temperature as the incoming flue gases). Since the maximum is 

unattainable, effectiveness is always less than 100%. 

The graph on page 102 relates combustion air temperature to flue gas temperature 

and recuperator effectiveness. 

To predict air preheat, read up from the flue gas temperature to the line 

representing the effectiveness of the exchanger, then left to air preheat. 

101

Figure 1: 

Heat Exchanger 

Effectiveness Curves 

Based on Combustion Air 

Entering at 60° F. 

Combustion Air Preheat, °F 

1500 

1000 

500 

0 

0 

500 

1000 

% Effectiveness 

90% 80% 70% 60% 50% 

1500 2000 

Flue Gas Temp. Entering Exchanger, °F 

102 

2500 

3000 

40% 

30% 

20% 

10%

TechNotes 

NFPA Requirements for Gas Burner Systems 

Reference: NFPA 86 – Ovens and Furnaces, 2003 Edition 


Section 2 

Sheet R-1 

The schematic and notes on the following page condense the gas burner system requirements of National Fire 

Protection Association (NFPA) 86 into an easy-to-use format. They should provide most of the engineering 

information required to lay out burner air and gas trains. Numbers in parentheses refer to the applicable 

paragraphs of the standard. 

In addition to the requirements shown on the schematic, NFPA 86 also requires that the combustion control 

system have the following features: 

1) All safety divices must be listed for their intended service (7.2.1), including purge and ignition timers 

(7.2.3). 

2) Safety control circuits must be single phase, one side grounded, with all breaking contacts in the 

“hot”, ungrounded, circuit protected line not exceeding 120V. (7.2.11) 

3) Prior to energizing spark or lighting pilot, a timed pre-purge of at least four standard cubic feet of air 

per cubic foot of heating chamber volume is required (7.4.1). 

a) Airflow must be proven & maintained during the purge. 

b) Safety shutoff valve must be closed and when the chamber input exceeds 400,000 Btu/hr 

(117 kW) it must be proved closed and interlocked. Proof of closure can be achieved by either a 

proof of closure switch on at least one valve or a valve proving system. 

4) Exceptions to a re-purge are allowed for momentary shutdowns if (any one): (7.4.1.5) 

a) Each burner is supervised, each has safety shutoff valves, and the fuel accumulation in the 

heating chamber can not exceed 25% of lower explosive limit. 

b) Each burner is supervised, each has safety shutoff valves, and at least one burner remains on in 

same chamber. 

c) The chamber temperature is more than 1400°F (760°C). 

5) Exception to the pre-purge is allowed for explosion resistant radiant tube systems. (7.4.1.4) 

6) All safety interlocks must be connected in series ahead of the safety shutoff valves. Interposing 

relays are allowed when the required load exceeds the rating of available safety contacts or where 

safety logic requires separate inputs, AND the contact goes to a safe state on loss of power, AND 

each relay serves only one interlock. (7.2.7) 

7) Any motor starters required for combustion must be interlocked into the safety circuit. (7.6.3) 

8) A listed manual reset excess temperature limit control is required except where the system design 

can not exceed the maximum safe temperature. (7.16) 

9) The user has the responsibility for establishing a program of inspection, testing, and maintenance 

with documentation performed at least annually. (7.2.5.2) 

The scope of NFPA 86 extends to all the factors involved in the safe operation of ovens and furnaces, and 

anyone designing or building them should be familiar with the entire standard. Copies can be purchased from: 

The National Fire Protection Association 

1 Batterymarch Park 

Quincy, MA 02269-9101 

800-344-3555 (508-895-8300 if outside U.S.) 

www.nfpa.org 

103

Gas 

1 

2 

3 

4 

Piping Schematic 

Item Description 

5 

6 

12 

7 

16 

10 

8 

9 9 

Air Flow 

Controls 

Gas Flow 

Controls 

Reference 

Paragraph 

6.2.5.3 

6.2.5.1 

6.2.5.3.3 

6.2.5.4 

6.2.5.4 

6.2.5.4.8 

7.7.1.8 

7.7.2.1 

7.7.1.9 

7.7.2.2 

7.7.2.3 

7.8.1 

7.8.2 

7.9.2 

7.9.2.1 

*Underwriters Laboratory (UL) listing is accepted throughout the United States. Listed products can be found in the UL Gas and Oil 

Equipment Directory, available from Underwriters Laboratory, Inc. Publications Stock, 333 Pfingsten Road, Northbrook, IL 60062-2096. 

Factory Mutual (FM) listed equipment is also acceptable in most jurisdictions and can be found in the FM Approval Guide available from 

Factory Mutual Research Corporation, 115 Boston-Providence Turnpike, Norwood, MA 02062. 

8 

11 11 

1 Facility to install drip leg or sediment trap for each fuel supply line. Must be a minimum of 3” long. 

2 Individual manual shutoff valve to each piece of equipment. 1/4 turn valves recommended. 

3 Filter or strainer to protect downstream safety shutoff valves. 

4 Pressure regulator required wherever plant supply pressure exceeds level required for proper burner function 

or is subject to excessive fluctuations. 

5 Regulator vent to safe location outside the building with water protection & bug screen. 

Vent piping not required for listed regulator/vent limiter combination. Vent piping not required for ratio 

regulator/zero governor. 

6 Gas pressure switches may be vented to regulator vent lines if backloading won’t occur. 

7 Over pressure protection required if gas pressure at regulator inlet exceeds rating of any downstream part. 

8 Two listed* safety shutoff valves required for each main and pilot gas burner system. A single valve can be 

used for explosion resistant radiant tube systems. 

9 Visual position indication required on safety shutoff valves to burners or pilots in excess of 150,000 Btu/hr 

(44 kW). 

10 Proof of closure switch or valve proving system required for capacities over 400,000 Btu/hr (117 kW). 

11 Permanent and ready means for checking leak tightness of safety shutoff valves. 

12 Listed* low gas pressure switch (normally open, makes on pressure rise). 

13 Listed* high gas pressure switch (normally closed, breaks on pressure rise). 

14 Flame Supervision: 

Piloted burners 

- Continuous pilot: Two flame sensors must be used, one for the pilot flame and one for the main burner flame. 

- Intermittent pilot: Can use a single flame sensor for self-piloted burners (from same port as main, or 

has a common flame base and has a common flame envelope with the main flame). 

- Interrupted pilot: A single flame sensor is allowed. 

Line, Pipe, Radiant burners 

- If the burners are adjacent and light safely and reliably from burner to burner, then a single sensor is 

allowed if it is located at the farthest end from the source of ignition. 

15 Spark Ignition: 

Except for explosion resistant radiant tube systems, direct spark igniters must be shut off after main burner 

trial-for-ignition. 

If a burner must be ignited at reduced input (forced low fire start), an ignition interlock must be provided to 

prove control valve position. 

Trial-for-ignition of the pilot or main must not exceed 15 seconds. An exception is allowed where fuel 

accumulation in the heating chamber can not exceed 25% of the lower explosive limit and the authority 

having jurisdiction approves a written request for extended time. 

16 Listed* combustion air flow or pressure proving switch (normally open, makes on pressure rise). 

10 

104 

11 

13 

15 

14 

7.9.2.2 

7.4.2.4 

7.15 

7.4.2 

7.6.2

Tech Notes 

IRI Requirements For Gas Burner Systems 

Reference: IM.4.2.0 & IM.4.2.1, June 1, 2000 


105 

Section 2 

Sheet R-2 

These schematic and notes condense the gas burner system requirements of GE Global Asset Protection 

Services - Industrial Risk Insurers (IRI) publications “IM.4.2.0 OVENS AND FURNACES - NFPA 86-1999” and 

“IM.4.2.1 HEAT TREAT FURNACES WITH INTERNAL QUENCH TANKS”. They should provide most of the 

engineering information required to lay out burner air and gas trains. IRI follows the requirements of NFPA 86 but 

makes additional clarifications and changes for increased safety. 

In addition to the requirements shown on the following schematic, IRI also requires that the combustion control 

system have the following features. Numbers in parenthesis reference the paragraphs in IM.4.2.0, IM.4.2.1, and 

NFPA 86. 

1) NFPA: Safety control circuits must be single phase, one side grounded, with all breaking contacts in the 

“hot”, ungrounded, circuit protected line and not exceed 120V. IRI: Any time delay used to avoid nuisance 

shutdowns from momentary power fluctuations cannot exceed 5 seconds and any timer must not be 

adjustable above this maximum. (5-2) 

2) NFPA: Prior to energizing spark or lighting pilot, a timed pre-purge of at least four standard cubic feet of 

air per cubic foot of heating chamber volume is required. IRI: Any adjustable purge timer must clearly 

show its setting, have limited access, and be periodically inspected. Any employee with access must be 

trained on its setting and consequences if not set properly. (5-4.1.2) 

a. NFPA: Airflow must be proven and maintained during the purge. IRI: The location of pressure 

switch sensing points must be analyzed against all other conditions (such as dirt accumulation 

and damper positions in the system) to assure it will truly prove the required airflow. (5-4.1.2.1) 

b. NFPA: Where the capacity exceeds 400,000 Btu/hr (117kW) at least one of the safety shutoff 

valves must be proved closed and interlocked to the purge. IRI: Both safety shutoff valves shall 

be proved closed and interlocked. (5-7.2.2) 

3) IRI: The trial for ignition for pilots or main burners must not exceed 10 seconds. (5-4.2.1, 5-4.2.2) 

Directly control the spark from a listed flame safeguard. (5-2.3) 

4) NFPA: All safety interlocks must be connected in series ahead of the safety shutoff valves. Interposing 

relays are allowed when the required load exceeds the rating of available safety contacts, or where the 

safety logic requires separate inputs, AND the contact goes to safe state on loss of power, AND each 

relay serves only one interlock. IRI: An interposing relay can be powered by more than one safety limit if 

the safety shutoff valves derive power in series through the limits. When one limit opens then the fuel is 

shutoff to all burners that use the interposing relay as a permissive. (5-2.7) 

5) NFPA: Any motor starters, circulation, and exhaust fans required for safe combustion or purge must be 

proven. (5-6.3) IRI: Use a rotation switch if pressure switches or sail switches are not suitable. (5-5.1) 

6) NFPA-IRI: A listed manual reset excess temperature limit control is required except where the system 

design cannot exceed the maximum safe temperature. (5-16) 

7) NFPA-IRI: Piping and electrical schematics of the proposed system must be submitted to the local IRI 

office in whose jurisdiction the system will be located. Drawings must include the various device settings, 

switch positions, configurations and notes on options. Stamped approval is required before construction 

begins. (1-4) 

8) NFPA-IRI: The user has the responsibility to establish a program of inspection, testing, and maintenance 

with documentation performed at least annually. (5-2.5.2)

1 

Gas 

2 

3 


4 

5 

6 

12 

Piping Schematic 

1 Facility to install drip leg or sediment trap for each fuel supply line. Must be a minimum of 3” long. 

7 

16 

2 Individual manual shutoff valve to each piece of equipment. 1/4 turn valves recommended. Must be in an 

accessible location near the floor. 

3 Filter or strainer to protect downstream safety shutoff valves. 

4 Pressure regulator required wherever plant supply pressure exceeds level required for proper burner function 

or is subject to excessive fluctuations. 

5 Regulator vent to safe location outside the building with water protection & bug screen. 

Vent piping can terminate inside the building when gas is lighter than air, vent contains restricted orifice, 

and there is sufficient building ventilation, where there are high clearances between the equipment and 

roof and there are no ignition sources. 

Vent piping not required for lighter than air gases at less than 1 psi, vent contains restricted orifice, and 

there is sufficient ventilation. Vent piping not required for ratio regulator. 

6 Gas pressure switches may be vented to regulator vent lines if backloading won’t occur. No vent line 

required if switch has no diaphragm. 

7 Relief valve required if gas pressure at regulator inlet exceeds rating of safety shutoff valve. Physical 

location can be upstream to meet application requirements. 

8 Two listed* safety shutoff valves required for each main and pilot gas burner system. Both safety shutoff 

valves must close after interruption of interlocks, combustion safeguard, or operating controls; no exceptions 

allowed for multiple burner systems. A single valve can be used for explosion resistant radiant tube systems. 

9 Position indication (not proof-of-closure) required on safety shutoff valves to burners or pilots in excess of 

150,000 Btu/hr (44 kW). Electrical indicators must not replace mechanical indicators. 

10 For capacities over 400,000 Btu/hr (117 kW) both safety shutoff valves must have a closed position switch to 

interlock with the pre-purge. 

11 Permanent and ready means for checking leak tightness of safety shutoff valves. Test in progressive 

intervals starting weekly, monthly, quarterly, then annually. 

12 Listed* low gas pressure switch (normally open, makes on pressure rise). 

13 Listed* high gas pressure switch (normally closed, breaks on pressure rise). 

14 Flame Supervision: 

Piloted burners 

- Continuous pilot: Two flame sensors must be used, one for the pilot flame and one for the main burner flame. 

- Intermittant pilot: Can use a single flame sensor for self-piloted burners (from same port as main, or 

has a common flame base and has a common flame envelope with the main flame). 

- Interrupted pilot: A single flame sensor is allowed. 

Line, Pipe, Radiant burners 

- If the burners are adjacent and light safely and reliably from burner to burner, then a single sensor is 

allowed if it is located at the farthest end from the source of ignition. 

Continuous (>24 hr) operation with UV scanners must use self checking style scanners (or use flame rods 

instead). 

10 

8 

9 

106 

17 

8 

10 

9 

Air Flow 

Controls 

11 

13 

Gas Flow 

Controls 

15 

14 

Reference 

Paragraph 

4-2.4.4 

4-2.4.1 

4-2.4.3 

4-2.4.5.1 

4-2.4.5.2 

4-2.4.5.5 

5-7.1.7 

5-7.2.1 

5-7.1.2 

5-7.1.8 

5-7.2.2 

5-7.2.3 

5-8.1 

5-8.2 

5-9 

5-9.2.1 

5-9.2.2 

5-9.2 

Continued on next page

Continued from previous page 


15 Spark Ignition: 

Except for explosion resistant radiant tube systems, direct spark igniters must be shut off after main 

burner trial-for-ignition. 

If a burner must be ignited at reduced input (forced low fire start), an ignition interlock must be provided to 

prove control valve position. 

Trial-for-ignition of the pilot or main must not exceed 10 seconds. An exception is allowed where fuel 

accumulation in the heating chamber can not exceed 25% of the lower explosive limit and the authority 

having jurisdiction approves a written request for extended time. 

Manual (pushbutton) ignition systems must be designed to prevent further spark after the trial-for-ignition 

until a full purge is first completed. 

16 Listed* combustion air flow or pressure proving switch (normally open, makes on pressure rise). 

17 A Listed* normally open (N.O.) vent valve with vent pipe run to a safe outside location is required when the line 

capacity exceeds 400,000Btu/hr (117kW). Do not manifold to other vent lines. Size the vent line according to the 

following table. 

Fuel Line Size Vent Line Size 

1½” 

2” 

2½” 

3½” 

4” 

5½” 

6½” 

8” 

*Underwriters Laboratory (UL) listing is accepted throughout the United States. Listed products can be found in the UL Gas and Oil 

Equipment Directory, available from Underwriters Laboratory, Inc. Publications Stock, 333 Pfingsten Road, Northbrook, IL 60062-2096. 

Factory Mutual (FM) listed equipment is also acceptable in most jurisdictions and can be found in the FM Approval Guide available from 

Factory Mutual Research Corporation, 115 Boston-Providence Turnpike, Norwood, MA 02062. 

107 

¾” 

1” 

1¼” 

1½” 

2” 

2½” 

3” 

3½” 

As an alternate to using a vent valve, use a valve tightness proving system that is automatically activated 

upon startup and shutdown 

More information can be obtained by contacting: 

Industrial Risk Insurers 

85 Woodland Street 

Hartford, CT 06102-5010 

860-520-7329 

860-520-7559 fax 

http://www.industrialrisk.com 

National Fire Protection Association 

1 Batterymarch Park 

Quincy, MA 02269-9101 

800-344-3555 

508-895-8300 

http://www.nfpa.org 

Reference 

Paragraph 

5-15.2 

5-15.1 

5-4.2.2 

5-15 

5-6.4 

5-7.2.1

Tech Notes 

Heating Values of Flammable Liquids 


Section 3 

Sheet I-1 

Designers of fume incinerators are sometimes concerned about the heating 

value of the solvents being incinerated. The table below lists approximate 

heating values of various commercial solvents and flammable liquids, 

calculated from the references at the bottom of page 109. 

Gross Heating Value 

Liquid Btu/U.S. Gallon Btu/lb. 

Acetone 87,360 13,040 

n-Amyl Acetate 105,670 14,410 

sec-Amyl Acetate 105,670 14,410 

Amyl Alcohol 110,290 16,220 

Benzene (Benzol) 132,150 18,100 

n-Butyl Acetate 97,480 13,250 

n-Butyl Alcohol 104,760 15,640 

sec-Butyl Alcohol 104,760 15,640 

Butyl Cellosolve (Glycol Monobutyl Ether) 105,630 14,040 

Butyl Propionate 106,060 14,130 

Camphor 143,010 17,150 

Carbon Disulfide 61,210 5,650 

Cellosolve (Ethylene Glycol Monoethyl) 91,960 11,790 

Cellosolve Acetate (Ethylene Glycol Monoethyl Ether Acetate) 

87,140 10,720 

Chlorobenzene-mono 105,420 11,490 

m- or p-Cresol 122,870 14,730 

Cyclohexane 130,300 20,050 

Cyclohexanone 117,900 15,710 

p-Cymene 146,000 19,450 

Denatured Alcohol 68,670 * 9,930 * 

Dibutyl Phthalate 109,630 13,150 

o-Dichlorobenzene 86,330 7,960 

N-Dimethyl Formamide 85,340 11,370 

p-Dioxane (Diethylene Dioxide) 89,380 10,720 

Ethyl Acetate 82,420 10,990 

Ethyl Alcohol 84,250 12,770 

Ethyl Ether 93,730 16,060 


* Approximate; liquid is a mixture whose composition may vary. 

108

References 

Gross Heating Value 

Liquid Btu/U.S. Gallon Btu/lb. 

Ethyl Lactate 78,990 9,470 

Ethyl Methyl Ether 86,700 14,850 

Ethyl Propionate 90,970 12,290 

Gasoline 129,000 * 21,050 * 

Hexane 113,850 20,700 

Kerosene (Fuel Oil #1) 131,000–137,000 * 19,700–19,900 * 

Methyl Acetate 71,610 9,300 

Methyl Alcohol 63,490 9,620 

Methyl Carbitol (Diethylene Glycol Methyl Ether) 89,650 10,340 

Methyl Cellosolve 81,190 10,080 

Methyl Cellosolve Acetate 79,530 9,470 

Methyl Ethyl Kerosene (2-Butanone) 97,710 14,580 

Methyl Lactate 80,160 8,810 

Nitrobenzene 90,170 9,010 

Nitroethane 50,190 5,470 

Nitromethane 17,010 1,850 

1-Nitropropane 66,290 7,950 

2-Nitropropane 65,760 7,950 

Propyl Acetate 85,770 11,430 

Propyl Alcohol 96,560 14,410 

iso-Propyl Alcohol 93,160 14,120 

n-Propyl Ether 109,280 17,470 

Pyridine 122,210 14,920 

Toluene 131,970 18,330 

Turpentine 163,500 * 20,000 * 

Vinyl Acetate 71,610 9,540 

o-Xylene 135,870 18,610 

* Approximate; liquid is a mixture whose composition may vary. 

NFPA 325M-1984, Fire Hazard Properties of Flammable Liquids, Gases, and 

Volatile Solids. 

Handbook of Chemistry and Physics, 40th Edition, 1959. 

109

Tech Notes 

Immersion Tube Sizing 

General Remarks 

Section 3 

Sheet L-1 

In 1944, AGA Testing Laboratories published Research Bulletin No. 24, “Research 

in Fundamentals of Immersion Tube Heating With Gas”. This landmark 

paper established beyond a doubt that the thermal efficiency of immersion 

tubes was strictly a function of their length—tube diameter had 

no effect. From their tests, AGA also developed an empirical relationship 

between thermal efficiency, effective tube length and burner firing rate for 

immersion tubes in boiling water: 

E =20log L2 

R +71 

where E = thermal efficiency, % 

L = effective tube length, ft. 

R = burner input rate, 1000’s of Btu/hr 

Effective tube length is the total centerline length of the tube immersed in 

water, including elbows, plus 1.1 feet for each elbow or return bend. 

This equation is the basis of the tube sizing charts in Eclipse literature. 

The fact that tube diameter had no effect on efficiency came as a shock to 

many people, but it makes sense when you think about it. Increasing the 

tube diameter increases the heat transfer surface, but it also produces 

lower gas velocity inside the tube, thus promoting a thicker gas boundary 

layer along the inside walls of the tube. This leads to poorer heat transfer. 

AGA’s studies determined that the loss in convection heat transfer almost 

exactly offset the gain in transfer surface. 

Over 40 years have passed since this paper was published. Far more sophisticated 

heat transfer equations have been developed, and we now have 

computers to perform the calculations, yet no one has been able to make a 

significant improvement to the speed and accuracy of AGA’s equation. 

The curves in the graph on page 111 were calculated from the AGA equation. 

110

Figure 1: 

Immersion Tube 

Efficiency vs. Length 

Burner Design 

Figure 2: 

Burner Design vs. 

Firing Rate 

Effective Tube Length, In Feet 

150 

100 

50 

% 

Efficiency 

60 

65 

70 

75 

80 

Heat Transfered To Tank, Btu/hr. (In Million’s) 

If heat transfer requirements don’t determine immersion tube diameters, 

what does? 

Burner design does—more specifically, the burner’s ability to fire against 

the back pressure of the immersion tube. 

Atmospheric burners operate at very low mixture pressures and depend on 

natural draft to pull secondary air into the tube. Consequently, the firing 

rate has to be kept low to avoid hot gases backing out of the tube around 

the burner head. 

Sealed, forced draft burners operate at higher pressures, so they can be 

used to push tubes to higher firing rates. The operating pressures of the 

combustion system determine just how hard the tube can be fired. That’s 

why Immerso-Jet small bore burner systems, with their high operating 

pressures, can operate satisfactorily at higher inputs per sq. in. of tube 

cross-section than packaged IP burners. Figure 2 lists approximate maximum 

firing rates in Btu/sq. in. of tube cross-section for various types of 

burner systems. 

60% 

0 0 1 2 3 4 5 

70% 

65% 

75% 

Max. Firing rate, 

Btu/Sq. In. of 

Burner System Type Tube Cross-Section 

Atmospheric, natural draft, 7' high stack 7000 - 8000 

Atmospheric with eductor, 0.2" w.c. draft 15,000 - 18,000 

Atmospheric with eductor, 0.4" w.c. draft 21,000 - 25,000 

Packaged forced draft, low pressure fan 15,000 - 35,000 

Sealed nozzle-mix, high pressure blower 30,000 - 85,000 

Small bore nozzle-mix 80,000 - 180,000 

111 

Effective 

Length, ft. 

.47r 

.771r 

1.273r 

2.113r 

3.523r 

where r = 

heat 

transferred 

to the tank, 

Btu/hr X 1000 

80% 

Efficiency

Tech Notes 

Submerged Combustion 

Section 3 

Sheet L-2 

Process Description: Submerged combustion is the practice of heating liquids by bubbling a 

burner’s hot combustion products through them. The process, which originated 

over 100 years ago, was first used to generate low pressure steam, 

but later became popular as a way to concentrate chemical solutions by 

evaporation. It is also viewed as an efficient way to heat water solutions to 

moderate temperatures, although its success has been somewhat spotty in 

this application. It agitates the bath and causes the water to become more 

acidic as CO 2 in the combustion products dissolves in the bath. Depending 

on the process, these features can be either advantages or drawbacks. 

Combustor Description: 

System Efficiency: 

Over the years a variety of designs have evolved, but most modern units 

are some version of either the single-tube or manifold design. 

Single Tube 

Combustor Manifold Type Combustor 

Single-tube units have a relatively small coverage area, so their use is restricted 

to tanks with fairly confined dimensions. On the other hand, manifold-type 

combustors can be custom-designed to fit tanks of any reasonable 

dimensions without the need to locate the combustor near the center 

of the tank. This permits submerged combustors to be used on dip tanks 

and other jobs where the tank volume must be free of obstructions. 

Submerged combustion gets its reputation for high efficiency from the fact 

that the combustion gases come into direct contact with the liquid, creating 

excellent heat transfer. Below about 140° F, all the water vapor in the 

combustion products condenses into the bath, releasing its latent heat of 

vaporization and producing thermal efficiencies of 90-95%, based on the 

higher heating value of the fuel. 

112

Figure 1: 

Thermal Efficiency 

of a Submerged 

Combustion System 

Burning Natural Gas at Sea Level 

System Design: 

Tank Depth: 

Combustor Tube: 

Above 140° F water begins to vaporize, and the efficiency drops quickly. 

One unusual effect of bubbling combustion products through water is that 

it lowers the water’s boiling point. For natural gas burned at sea level, the 

boiling point is about 190° F; for propane, it is about 180° F. Higher altitudes 

will depress the boiling point even further. If the purpose of the system 

is to boil water away, this is an asset, but if its purpose is only heating 

water, process thermal efficiency is zero at the boiling point. 

From the efficiency curve below, you can see that at 165° F liquid temper– 

ature, a submerged combustion system has a thermal efficiency of 70%, 

equivalent to a conventional immersion tube system. At higher temperatures, 

it is less efficient. To compete with an 80% efficient immersion tube 

such as the IJ Small Bore system, a submerged combustion system would 

have to operate at 155° F or less. 

% Thermal Efficiency 

100 

80 

60 

40 

20 

0 

60 80 100 120 140 160 180 200 

Water Temperature, °F 

Custom-built submerged combustion units are available, although many 

successful jobs have been done with standard burner equipment. 

The tank must be deep enough to provide at least 16-20" of bubble path 

through the liquid. Shallower tanks will not allow time for optimum heat 

transfer. Beyond 20", the improvement in heat transfer is negligible, but 

the tank may have to be deeper simply to accommodate the length of the 

combustion tube, which has to be large enough to allow completion of the 

flame. 

All portions of the tube immersed in the tank can be bare metal. Customary 

practice is to locate the burner mounting flange within a few inches of the 

liquid level so the entire tube can be left bare. Be sure to choose an alloy 

that won’t corrode in the solution. 

113

Distribution Tubes: 

Supply Pressures: 

Burner: 

Moisture Protection: 

Operating Sequence: 

Safety: 

Single-tube combustors are often provided with a perforated conical skirt 

on the bottom to aid in breaking up and distributing the flue gases. Manifold 

systems are subject to a lot of design variations, but a few general 

rules apply: 

• Large tanks will require distribution pipes to carry the combustion products 

throughout the tank. Don’t depend on a single combustor isolated 

in one corner to provide uniform tank heating. 

• Gas distribution openings in the pipe manifolds are most commonly 

single rows of drilled holes, although slot openings have also been used. 

There aren’t any universally accepted rules on hole sizing, but anything 

smaller than 1/4" diameter is probably a waste of effort. 

• The effect of hole location (facing up, down or sideways) on heat transfer 

is probably negligible. However, facing the holes downward aids draining 

the water out of the manifold when the system is started up. Be 

sure to provide a couple of inches clearance between the manifolds and 

the tank floor (more, if you expect sludge or debris to accumulate). 

• Total area of the distribution holes is, again, a matter of individual 

preference, but one square inch of opening for every 50-60,000 Btu/hr 

firing rate gives a good compromise between even distribution and low 

pressure drops. 

• Design the manifold so it is free to expand without constraint. Otherwise, 

broken welds and leaks are sure to result. 

• When filled with combustion gases, the distribution tube will become 

buoyant and try to float. Long, cantilevered tubes will vibrate and thrash 

around the tank. Be sure they’re properly anchored to the tank bottom. 

Remember that the head pressure of the liquid in the tank has to be added 

to all the normal air and gas supply pressures. 

Nozzle mix burners are strongly preferred; the flashback tendencies of premix 

burners can be aggravated by fluctuations in system back pressure. 

Flame length should be no more than 1/2 to 2/3 the length of the combustor 

tube, or the flame is apt to be quenched, forming CO and aldehydes. 

High levels of humidity are normal around tanks heated with submerged 

combustors. Condensation will tend to collect on spark igniters, flame rods 

and scanner cells. Provide them with air purging if this is expected to be a 

problem. Use weather-resistant boots on electrode connectors, and all electrical 

wiring and control boxes should be selected or situated to exclude 

moisture. Combustion air blowers should be located where they won’t draw 

in excessively humid air. 

This will be dictated in part by safety requirements, but all systems should 

have a prepurge to remove the water from the combustor tube and distribution 

manifold. Regardless of burner capacity, low fire lightoff is strongly 

recommended. 

Depending on the tank volume and the area over which the combustion 

gases are bubbled, the liquid surface will be agitated anywhere from a gentle 

rolling motion to a violent boil. Splashing and spilling over the sides of the 

tank can occur, and precaution should be taken to avoid exposing workers 

and equipment to hot and/or corrosive liquid. 

114

References: 

Thermal Manual of Submerged Combustion, Thermal Research & Engineering 

Corp., Conshohocken, PA 1961. 

“Tank & Solution Heaters for the Chemical Industry” AGA Information letter 

No. 115, N.E. Keith, A.G.A., New York, 1960. 

115

Tech Notes 

Immersion Tubes–What Will The Stack Temperature Be? 

Reference: 

Figure 1: 

Available Heat vs. Flue 

Gas Exit Temperature, °F 


Section 3 

Sheet L-3 

Customers laying out immersion tube systems frequently ask what stack 

temperatures they should expect. You can make a good approximation from 

the available heat chart below. The heat transferred through an immersion 

tube is the available heat in that system; everything else is flue gas loss, so 

it’s easy to calculate flue gas temperature by working backward on the 

available heat chart. All you need to know is the tube efficiency and the 

amount of excess air at high fire. 

For example, let’s say you had an immersion system operating at 70% 

thermal efficiency and 25% excess air at high fire. Starting at 70% available 

heat (with available heat equal to efficiency), read across until you hit 

the 25% excess air curve and then drop straight down to get the flue gas 

exit temperature, which, in this case, is 950°F. 


100 

90 

80 

70 

60 

50 

40 

30 

20 

10 

350% 

400% 

500% 

600% 

800% 

1000% 

1200% 

Based On Birmingham Natural Gas (1002 Btu/Cu. ft., 0.6 Sp. Gr.) 

0% 

10% 

0 

0 200 600 1000 1400 1800 2200 2600 3000 

116 

250% 

300% 

200% 

150% 

% Excess Air 

100% 

Flue Gas Exit Temperature, °F 

50% 

25%

Tech Notes 

Determining % O 2 in a Recirculating System 

Data Needed: 

Fresh 

Makeup 

Air 

Q M 

Combustion 

Air 

Q A 

Burner 

Section 3 

Sheet O-1 

To determine O 2 content in a recirculating system, you need to know: 

Q X =oven exhaust volume, acfm 

T X =oven exhaust temperature 

Fuel 

Q F 

Oven 

Q F =maximum fuel flow to burner, scfm 

Exhaust, Q at Temperature, 

X 

TX R =stoichiometric air-fuel ratio (e.g., 10:1 for natural gas, 25:1 for propane, 

or whatever) 

117 

(continued on page 118)

Procedure: 1. Determine scfm of exhaust. 

Example 

Q E in scfm = Q X in acfm x 

520 

T X + 460 

The temperature correction factor, 

520 

TX + 460 

, equals the specific gravity 

of the exhaust at temperature T . X 

For simplicity’s sake, assume the exhaust has properties nearly equal 

to air. Then you can use the specific gravity figures on page 21 of the 

Eclipse Combustion Engineering Guide. 

2. For the oven to be balanced, the sum of fuel to the burner (Q F ), air to 

the burner (Q A ), and fresh makeup air (Q M ) must equal the exhaust 

volume: 

Q E =Q F+Q A +Q M 

3. Determine the portion of makeup and combustion air which is consumed 

in burning the fuel. This equals: 

RxQ F 

The remaining unconsumed fresh air determines the oxygen level in 

the oven. It equals: 

Q E –Q F– Rx Q F 

4. Calculate oxygen content in oven, assuming 20.8% oxygen in the fresh 

air stream. 

%O 2 = 20.8 x Q E –Q F– Rx Q F 

Q E 

or in its simplest form: 

%O 2 = 20.8 x Q E – 1+R Q F 

Q E 

For example, we have an oven exhausting 2000 acfm at 600° F. The 

burner is rated at 1.8 million Btu/hr on 1000 Btu/cu.ft. natural gas 

(10:1 stoichiometric ratio). 

At 600° F, the specific gravity of air is .500, so Q E = (2000) (.500) = 1000 

scfm 

Q F , the maximum fuel input, is 1,800,000 Btu/hr divided by 1000 Btu/ 

cu.ft. = 1800 scfh. 1800 cfh divided by 60 minutes = 30 scfm 

R, the stoichiometric air-gas ratio, is given as 10:1, so: 

%O 2 = 20.8 x 

118 

1000 – 1 +10 30 

1000 

= 20.8 x 

670 

1000 = 13.94%O 2

Litho in U.S.A.

Eclipse Engineering Guide

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