ES&H Manual

Flammable Gas Supplement

 

 

 

Chapter 7 – Heats of Combustion

 

 

 

Hydrogen equivalent, Q

The heat of combustion for other gases is used to determine the hydrogen equivalent mass, Q, for use in Figure 1 in the Flammable Gas Supplement Chapter 1 Storage/Use of Flammable Gases.  For example the table indicates that ethane has 0.36 times the heat of combustion of hydrogen per unit mass.  Therefore 1.7 kg of ethane is equivalent to 0.6 kg of hydrogen in determining Risk Class.

 

Heats of Combustion

The following table of heats of combustion may be useful for calculating hydrogen equivalents.  The heats of combustion can be found in, for example, The Handbook of Chemistry and Physics, 77th Edition, 1997.

 

 

 

Gross Heat of Combustion

Gas

Molecular Weight

(kj/g)

Relative to that of Hydrogen

hydrogen-H2

2

143

1.00

deuterium- D2

4

72

.50

methane-CH4

16

55

.39

acetylene-C2H2

26

50

.35

ethane-C2H6

30

51

.36

propane-C3H8

44

50

.35

isobutane-C4H10

58

49

.34

dimethyl ether- (CH3)2O

46

32

.22

 

 

 

ISSUING AUTHORITY

TECHNICAL

POINT-OF-CONTACT

APPROVAL DATE

EXPIRATION DATE

REV.

 

 

ESH&Q Division

Jack Segal

June 15, 2011

June 15, 2016

1

 

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