GPA Standard 2145-09
Table of Physical Properties
for Hydrocarbons and Other
Compounds of Interest to the
Natural Gas Industry
Adopted 1942
Revised 1957,1962, 1966, 1971, 1975, 1977, 1982, 1983, 1984, 1985, 1986, 1988,
1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 2000, 2003, 2005, 2007, 2009
Reprinted 1997, 1998
Gas Processors Association
6526 East 60th Street
Tulsa, Oklahoma 74145
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Copyright Gas Processors Association
Not for Resale, 09/09/2008 12:58:57 MDT
Licensee=BP International/5928366101
FOREWORD
The Table of Physical Properties for Hydrocarbons and Other Components of Interest to the Natural
Gas Industry, GPA Publication Standard 2145, provides the gas processing industry with a convenient
compilation of authoritative numerical values for the paraffin hydrocarbons and other compounds
occurring in natural gas and natural gas liquids as well as for a few other compounds of interest to the
industry. The physical properties selected are those considered most valuable for engineering and
analytical computations in gas processing plants and laboratories. Most properties are based upon two
NIST Standard Reference Databases: the Web Thermo Tables, WTT, (NIST SRSD-3) and the
Reference Fluid Thermodynamic and Transport Properties Database, REFPROP, (NIST SRD-23). The
data in this publication were checked, evaluated, and recalculated when necessary by Robert Chirico
and Eric Lemmon of the Physical and Chemical Properties Division of the Chemical Science and
Technology Laboratory at NIST in Boulder, Colorado. The listed flammability limits and octane
numbers were not evaluated at NIST and sources for these properties are provided in the references.
Some of the listed values result from other values in the tables by simple calculation. Numbers obtained
from such related data may differ from the tabulated values in the last digit because of numerical round
off, but the differences are within the standard uncertainty of the data. The value of the gas constant
used in the tables is 8.314472 J/(K·mol). Numerous values were updated from the previous edition of
GPA-2145 to provide full thermodynamic consistency between properties. This was accomplished
through consistent use of properties derived with the equations of state underlying the NIST REFPROP
database. Properties derived with these equations of state are inherently consistent. This publication
represents the first time for which thermodynamic consistency is assured for all properties listed in GPA2145. Required enthalpies of combustion at 298.15 K were taken from the NIST Web Thermo Tables
(WTT). These enthalpies of combustion are reprinted in the notes of this document. All adjustments of
these values to the selected temperatures of GPA-2145 were completed using consistent thermophysical
property values from the NIST REFPROP program.
The values of the physical properties for the components in GPA 2145, as well as those for many more
compounds, appear in the GPSA Engineering Data Book. Property values for compounds listed here in
GPA 2145-09 supersede those listed in the GPSA Engineering Data Book. For components not listed in
GPA 2145, the property values in GPA TP-17 may be used.
DISCLAIMER
GPA publications necessarily address problems of a general nature and may be used by anyone desiring
to do so. Every effort has been made by GPA to assure accuracy and reliability of the information
contained in its publications. With respect to particular circumstances, local, state, and federal laws and
regulations should be reviewed. It is not the intent of GPA to assume the duties of employers,
manufacturers, or suppliers to warn and properly train employees or others exposed, concerning health
and safety risks or precautions.
GPA makes no representation, warranty, or guarantee in connection with this publication and hereby
expressly disclaims any liability or responsibility for loss or damage resulting from its use or for the
violation of any federal, state, or municipal regulation with which this publication may conflict, or for
any infringement of letters of patent regarding apparatus, equipment, or method so covered.
"Copyright ©2008 by Gas Processors Association. All rights reserved.
No part of this Report may be reproduced without written
consent of the Gas Processors Association."
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Copyright Gas Processors Association
Not for Resale, 09/09/2008 12:58:57 MDT
by IHS under license with GPA
GPA 2145Provided
Page
2
Licensee=BP International/5928366101
PHYSICAL PROPERTIES OF SELECTED HYDROCARBONS
GPA STANDARD 2145-09 (FPS) becomes effective January 1, 2009
Component
Methane
Ethane
Propane
i-Butane
n-Butane
i-Pentane
n-Pentane
Molar Mass
Boiling Temperature *
16.0425
30.0690
44.0956
58.1222
58.1222
72.1488
72.1488
at 14.696 psia, °F
-258.66
-127.44
-43.80
10.85
31.12
82.09
96.91
-296.42
-297.01
-305.72
-254.96
-216.85
-256.90
-201.42
5000
800
188.62
72.644
51.567
20.474
15.576
0.3
340
2.5
0.35628
265.66
2.9704
0.50719
147.49
4.2285
0.56283
119.91
4.6925
0.58420
110.71
4.8706
0.62514
94.848
5.2120
0.63071
92.850
5.2584
0.5539
42.27
1.0382
79.24
1.5225
116.20
2.0068
153.16
2.0068
153.16
2.4911
190.12
2.4911
190.12
0.0116
0.0238
0.0347
0.0441
0.0470
0.0576
0.0606
6.417
59.138
442.38
10.123
37.488
280.43
10.428
36.391
272.22
12.386
30.637
229.18
11.933
31.801
237.89
13.843
27.414
205.07
13.721
27.658
206.89
-116.66
667.1
89.91
706.7
206.13
616.6
274.39
526.3
305.56
550.6
368.96
489.9
385.79
488.8
23892
1010.0
59729
22185
65897
22334
1769.7
66340
21491
90875
21654
2516.1
91563
21081
98924
21232
3251.9
99630
21137
102950
21300
3262.3
103740
20891
108880
21044
4000.9
109680
20923
110020
21085
4008.7
110870
909.4
1619
2315
3000
3011
3699
3707
9.548
16.710
23.871
31.032
31.032
38.193
38.193
219.6
210.4
183.0
157.0
165.8
147.6
153.7
0.5266
0.4028
1.3073
0.4079
0.3418
1.1932
0.9664
0.3873
0.3423
1.1316
0.6183
0.3866
0.3525
1.0969
0.5641
0.3949
0.3608
1.0947
0.5692
0.3828
0.3553
1.0775
0.5311
0.3879
0.3603
1.0764
0.5427
5.0
15.0
2.9
13.0
2.0
9.5
1.8
8.5
1.5
9.0
1.3
8.0
1.4
8.3
0.05
1.6
97.1
1.8
97.6
0.1
89.6
93.8
90.3
92.3
62.6
61.7
Triple Point Temperature
°F
Vapor Pressure *
at 100 °F, psia
Density of Liquid *
at 60 °F, 14.696 psia
Relative density at 60 °F/60 °F
API Gravity
Absolute density, lbm/gal
Density of Ideal Gas
at 60 °F, 14.696 psia
Relative density, air = 1.0
Density lbm/(1000 ft3)
Summation Factor
at 60 °F, psia-1
Volume *
at 60 °F, 14.696 psia
Liquid, gal/lbmol
Ft3 ideal gas/gal liquid
Ratio, ideal gas/liquid
Critical Conditions
Temperature, °F
Pressure, psia
Gross Heating Value *
at 60 °F, ideal reaction
Btu/lbm, fuel as liquid
Btu/gal, fuel as liquid
Btu/lbm, fuel as ideal gas
Btu/ft 3, fuel as ideal gas
Btu/gal, fuel as ideal gas
Net Heating Value
at 60 °F, ideal reaction
Btu/ft 3, fuel as ideal gas
Volume of Air to Burn One
Volume of Ideal Gas
Heat of Vaporization *
at 14.696 psia, °F
Btu/lbm at the boiling point
Specific Heat *
at 60 °F, 14.696 psia
C P , Btu/(lbm °F), ideal gas
C V , Btu/(lbm °F), ideal gas
k = C P /C V , ideal gas
C S , Btu/(lbm °F), sat. liq.
Flammability Limits
at 100 °F, 14.696 psia
Lower, volume % In air
Upper, volume % in air
Octane Number
Motor clear
Research clear
* For some compounds, values within this property group are for conditions different from those given in the row heading. See the notes
on pages 6 through 8 for details. Values in boldface type are different from those in the previous version of GPA-2145.
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Copyright Gas Processors Association
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GPA 2145
page 3
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PHYSICAL PROPERTIES OF SELECTED HYDROCARBONS
GPA STANDARD 2145-09 (FPS) becomes effective January 1, 2009
Component
Molar Mass
Boiling Temperature *
at 14.696 psia, °F
n-Hexane
n-Heptane
n-Octane
n-Nonane
n-Decane
Ethylene
Propylene
86.1754
100.2019
114.2285
128.2551
142.2817
28.0532
42.0797
155.68
209.08
258.12
303.37
345.42
-154.79
-53.72
-139.58
-131.08
-70.20
-64.21
-21.37
-272.49
-301.35
4.961
1.619
0.5349
0.1809
0.06148
227.3
0.66406
81.582
5.5364
0.68823
74.101
5.7379
0.70655
68.768
5.8907
0.72224
64.418
6.0215
0.73458
61.127
6.1244
0.52260
139.260
4.3571
2.9754
227.09
3.4597
264.05
3.9440
301.01
4.4283
337.97
4.9126
374.93
0.9686
73.92
1.4529
110.89
0.0776
0.0951
0.1128
0.1307
0.1556
0.0207
0.0327
15.565
24.380
182.38
17.463
21.730
162.56
19.391
19.570
146.39
21.300
17.816
133.28
23.232
16.334
122.19
453.8
436.9
512.56
396.8
564.22
360.7
610.52
330.8
652.19
305.0
20783
115060
20943
4755.9
115950
20680
118660
20839
5502.6
119570
20601
121350
20760
6249.0
122290
20543
123700
20701
6996.3
124650
20494
125510
20651
7742.9
126480
4404
5100
5796
6493
7190
1499
2182
45.355
52.516
59.677
66.839
74.000
14.323
21.484
144.0
136.2
129.9
124.1
118.8
207.4
188.7
0.3857
0.3626
1.0635
0.5285
0.3841
0.3643
1.0544
0.5268
0.3829
0.3655
1.0476
0.5240
0.3820
0.3665
1.0423
0.5192
0.3813
0.3673
1.0380
0.5155
0.3573
0.2865
1.2471
0.3567
0.3095
1.1525
0.6020
1.1
7.7
1.0
7.0
0.8
6.5
0.7
5.6
0.7
5.4
2.9
32.0
2.1
11.1
Triple Point Temperature
°F
Vapor Pressure *
at 100 °F, psia
Density of Liquid *
at 60 °F, 14.696 psia
Relative density at 60 °F/60 °F
API Gravity
Absolute density, lbm/gal
Density of Ideal Gas
at 60 °F, 14.696 psia
Relative density, air = 1.0
Density lbm/(1000 ft3)
Summation Factor
at 60 °F, psia-1
Volume *
at 60 °F, 14.696 psia
Liquid, gal/lbmol
Ft3 ideal gas/gal liquid
Ratio, ideal gas/liquid
9.6578
39.293
293.93
Critical Conditions
Temperature, °F
Pressure, psia
48.56
731.3
195.91
660.6
Gross Heating Value *
at 60 °F, ideal reaction
Btu/lbm, fuel as liquid
Btu/gal, fuel as liquid
Btu/lbm, fuel as ideal gas
Btu/ft 3, fuel as ideal gas
Btu/gal, fuel as ideal gas
21640
1599.7
20875
90954
21040
2333.0
91672
Net Heating Value
at 60 °F, ideal reaction
Btu/ft 3, fuel as ideal gas
Volume of Air to Burn One
Volume of Ideal Gas
Heat of Vaporization *
at 14.696 psia, °F
Btu/lbm at the boiling point
Specific Heat *
at 60 °F, 14.696 psia
C P , Btu/(lbm °F), ideal gas
C V , Btu/(lbm °F), ideal gas
k = C P /C V , ideal gas
C S , Btu/(lbm °F), sat. liq.
Flammability Limits
at 100 °F, 14.696 psia
Lower, volume % In air
Upper, volume % in air
Octane Number
Motor clear
Research clear
26
24.8
All values in this table are on the International Temperature Scale 1990 (ITS-90).
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Page 4
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PHYSICAL PROPERTIES OF SELECTED HYDROCARBONS
GPA STANDARD 2145-09 (FPS) becomes effective January 1, 2009
Component
Molar Mass
Boiling Temperature *
at 14.696 psia, °F
Carbon
Dioxide
44.0095
Hydrogen
Sulfide
34.0809
-109.24
-69.81
Nitrogen
Oxygen
Helium
Air
Water
28.0134
31.9988
4.0026
28.9625
18.0153
-76.54
-320.43
-297.33
-452.06
-317.64
211.95
-121.81
-346.00
-361.82
-455.75
-352.12
32.018
Triple Point Temperature
°F
Vapor Pressure *
395.0
at 100 °F, psia
0.95050
Density of Liquid *
at 60 °F, 14.696 psia
Relative density at 60 °F/60 °F
API Gravity
Absolute density, lbm/gal
0.81716
41.660
6.8129
0.79886
45.628
6.6602
0.80687
43.868
6.7271
1.1423
-7.630
9.5238
0.12486
1002
1.041
0.87586
30.055
7.3022
1.00000
10.000
8.3372
1.5195
115.97
1.1767
89.81
0.9672
73.820
1.1048
84.322
0.1382
10.547
1.0000
76.321
0.62202
47.473
0.0195
0.0239
0.00442
0.0072
0.00537
0.06510
6.4598
58.746
439.45
5.1171
74.16
554.76
4.1643
91.128
681.69
3.3599
112.95
844.89
3.8451
98.693
738.27
3.9663
95.678
715.72
2.1608
175.62
1313.7
87.76
1070.0
211.91
1305.3
-232.53
492.5
-181.43
731.4
-450.32
33.0
-221.12
549.1
705.11
3200.1
Density of Ideal Gas
at 60 °F, 14.696 psia
Relative density, air = 1.0
Density lbm/(1000 ft3)
Summation Factor
at 60 °F, psia-1
at 60 °F, 14.696 psia
Liquid, gal/lbmol
Ft3 ideal gas/gal liquid
Ratio, ideal gas/liquid
Critical Conditions
Temperature, °F
Pressure, psia
Gross Heating Value *
at 60 °F, ideal reaction
Btu/lbm, fuel as liquid
Btu/gal, fuel as liquid
Btu/lbm, fuel as ideal gas
Btu/ft 3, fuel as ideal gas
Btu/gal, fuel as ideal gas
6892.4
45905
7094.0
637.10
47248
1059.8
50.310
8835.4
Net Heating Value
at 60 °F, ideal reaction
Btu/ft 3, fuel as ideal gas
586.79
Volume of Air to Burn One
Volume of Ideal Gas
Heat of Vaporization *
at 14.696 psia, °F
Btu/lbm at the boiling point
7.1613
246.5
234.9
85.63
91.60
8.922
88.07
970.12
0.1992
0.1541
1.2929
0.6857
0.2383
0.1800
1.3236
0.5088
0.2483
0.1774
1.3996
0.2189
0.1569
1.3956
1.2404
0.7442
1.6667
0.2399
0.1714
1.4002
0.44478
0.33455
1.3295
1.0003
Specific Heat *
at 60 °F, 14.696 psia
C P , Btu/(lbm °F), ideal gas
C V , Btu/(lbm °F), ideal gas
k = C P /C V , ideal gas
C S , Btu/(lbm °F), sat. liq.
Flammability Limits
at 100 °F, 14.696 psia
Lower, volume % In air
Upper, volume % in air
4.3
45.5
Octane Number
Motor clear
Research clear
* For some compounds, values within this property group are for conditions different from those given in the row heading. See the notes
on pages 6 through 8 for details. Values in boldface type are different from those in the previous version of GPA-2145.
Copyright Gas Processors Association
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GPA 2145
Page 5
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No reproduction or networking permitted without license from IHS
Volume *
TABLE FOR NOTES AND REFERENCES
GPA STANDARD
Component
C1
C2
2
b
b
2
2
2
b
b
b
All
Molar Mass
Boiling Temperature
1
at 14.696 psia, °F
2
C3
i-C4
n-C4
i-C5
n-C5
n-C6
n-C7
d
d
d
d
b
b
d
d
d
d
d
d
d
d
2
2
2
2
2
2
2
2
2
2
2
2
2
2
3
3
2
2
3
d
d
3
d
d
3
d
d
3
d
d
3
3
3
3
3
l
l, m
l, m
l, m
m
m
Triple Point Temperature
2
°F
Vapor Pressure
at 100 °F, psia
Density of Liquid
at 60 °F, 14.696 psia
Relative density at 60 °F/60 °F
API Gravity
Absolute density, lbm/gal
Density of Ideal Gas
at 60 °F, 14.696 psia
Relative density, air = 1.0
Density lbm/(1000 ft3)
f
Summation Factor
at 60 °F, psia-1
2
Volume
at 60 °F, 14.696 psia
Liquid, gal/lbmol
Ft3 ideal gas/gal liquid
Ratio, ideal gas/liquid
g
g
g
Critical Conditions
Temperature, °F
Pressure, psia
Gross Heating Value
--```,`,``,`,,`,,,``,,`,,```,,``-`-`,,`,,`,`,,`---
at 60 °F, ideal reaction
Btu/lbm, fuel as liquid
Btu/gal, fuel as liquid
Btu/lbm, fuel as ideal gas
Btu/ft3, fuel as ideal gas
Btu/gal, fuel as ideal gas
i
g
Net Heating Value
at 60 °F, ideal reaction
Btu/ft3, fuel as ideal gas
Volume to Burn One Volume of Ideal
Gas
Heat of Vaporization
at 14.696 psia, °F
Btu/lbm at the boiling point
k
2
Specific Heat
at 60 °F, 14.696 psia
C P , Btu/(lbm °F), ideal gas
C V , Btu/(lbm °F), ideal gas
k = C P /C V , ideal gas
C S , Btu/(lbm °F), sat. liq.
2
2
c
Flammability Limits
at 100 °F, 14.696 psia
Lower, volume % In air
Upper, volume % in air
4
4
Octane Number
Motor clear
Research clear
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m
m
2145-09 (FPS)
n-C8
n-C9
n-C10
C 2=
C3 =
CO2
H2S
N2
O2
He
Air
H2O
a
c
c
c
c
d
3
3
2
2
2
2
2
2
2
2
3
3
3
c
c
3
d
d
3
c
c
c
c
d
d
d,e
d,e
d,e
d,e
d
d
d
d
e
h
h
e
h
h
e
h
h
e
h
h
2
2
2
2
2
2
2
2
2
2
2
2
d
d
3
j
j
j
n
c
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2
2
c
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c
c
c
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c
Molar Mass of Dry Atmospheric Air (g)
Mole Fraction (x i) Molar Mass (M )
Component
nitrogen
0.78102
28.0134
0.20946
31.9988
oxygen
argon
0.00916
39.948
carbon dioxide
0.00033
44.0095
neon
0.0000182
20.1797
0.0000052
4.0026
helium
methane
0.0000015
16.0425
0.0000011
83.798
krypton
0.0000005
2.01588
hydrogen
nitrous oxide
0.0000003
44.0128
carbon monoxide
0.0000002
28.0101
0.0000001
131.293
xenon
AIR
b
c
d
e
x i·M
21.87903
6.70247
0.365924
0.014523
0.000367
0.000021
0.000024
0.000092
0.000001
0.000013
0.000006
0.000013
28.9625
Shaded values were estimated by GPA for the hypothetical liquid state and were not re-evaluated
The referenced temperature is above the critical temperature.
The property is that of the liquid component at saturation pressure rather than at 14.696 psia.
Densities of liquid at the normal boiling temperature
f Gas constant R = 8.314472 J mol-1 K-1. [10.7316 psia ft3/(lbmol oR)] and 1 Btu = 1055.056 J
g Algebraically derived from the absolute density of the liquid
h Gas at 60 °F and liquid at the normal boiling point
i The basis for gross heating value is dry gas at 60 °F and 14.696 psia based upon the ideal
reaction, see GPA 2172 for conversion to other bases. Conversion of enthalpies of combustion at
T = 298.15 K given in reference 3 were converted to the conditions specified here with the
property values from reference 2. Heating values for H2S are based on SO2(g) and H2O as
products.
j Enthalpy of vaporization to the ideal-gas state
k Values are based on an oxygen mole fraction of 0.20946 for air.
l The + sign and number specify the number of cm3 of TEL (tetraethyl lead) added per gallon to
achieve the ASTM octane number of 100, corresponding to that of 2,2,4-trimethylpentane.
m Average value from octane numbers using more than one sample
n Enthalpy of sublimation
o For components not listed in GPA-2145, the property values listed in TP-17 may be used.
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NOTES FOR GPA STANDARD 2145-09 (FPS)
a ''The Molar Mass of Air is fixed by GPA to be 28.9625 in order to harmonize with ISO 6976-95
'Natural gas -- Calculation of calorific value, density, relative density and Wobbe index from
composition' and AGA 5-07 'Fuel Gas Energy Metering'. Individual components in Air may
change over time based on empirical data but the Molar Mass of Air, calculated from the table
shown below, will remain constant within this document for the purposes of, but not limited to,
the calculation of Gas Relative Density. The information in the table below should not be used
for individual component calculations. For information on individual components refer to the
appropriate Component Data Table.'' AGA 5-07 TABLE 7.17.1 follows.
PHYSICAL PROPERTIES OF SELECTED HYDROCARBONS
GPA STANDARD 2145-09 (SI) becomes effective January 1, 2009
Component
Molar Mass
Boiling Temperature *
at 101.325 kPa(abs), K
Methane
Ethane
Propane
i-Butane
n-Butane
i-Pentane
n-Pentane
16.0425
30.0690
44.0956
58.1222
58.1222
72.1488
72.1488
111.67
184.57
231.04
261.40
272.66
300.98
309.21
90.69
90.37
85.53
113.73
134.90
112.65
143.47
35000
5500
1369.4
531.21
378.49
151.51
115.67
0.3
300
0.35817
357.85
0.50796
507.50
0.56346
562.95
0.58478
584.25
0.62564
625.08
0.63119
630.62
0.5539
0.67848
1.0382
1.2717
1.5225
1.8649
2.0068
2.4581
2.0068
2.4581
2.4911
3.0514
2.4911
3.0514
0.00442
0.00910
0.0132
0.0168
0.0179
0.0220
0.0232
53.475
442.17
84.027
281.40
86.888
272.13
103.25
229.02
99.482
237.68
115.42
204.85
114.41
206.67
190.56
4599
305.32
4872.2
369.89
4251.2
407.81
3629
425.13
3796
460.35
3378
469.70
3370
55.575
37.706
51.604
18467
51.951
66.066
49.990
25370
50.369
93.934
49.038
27606
49.388
121.40
49.166
28725
49.546
121.79
48.593
30375
48.950
149.36
48.668
30691
49.045
149.65
33.95
60.43
86.42
112.0
112.4
138.1
138.4
9.548
16.710
23.871
31.032
31.032
38.193
38.193
510.8
489.4
425.6
365.1
385.7
343.3
357.6
2.2036
1.6853
1.3075
1.7054
1.4289
1.1935
4.0050
1.6191
1.4305
1.1318
2.5840
1.6162
1.4731
1.0971
2.3586
1.6511
1.5080
1.0949
2.3805
1.6003
1.4851
1.0776
2.2208
1.6216
1.5064
1.0765
2.2698
5.0
15.0
2.9
13.0
2.0
9.5
1.8
8.5
1.5
9.0
1.3
8.0
1.4
8.3
0.05
1.6
97.1
1.8
97.6
0.1
89.6
93.8
90.3
92.3
62.6
61.7
Triple Point Temperature
K
Vapor Pressure *
at 313.15 K, kPa(abs)
Density of Liquid *
at 288.15 K, 101.325 kPa(abs)
Relative density at 15 °C/15 °C
Absolute density, kg m-3
Density of Ideal Gas
at 288.15 K, 101.325 kPa(abs)
Relative density, air = 1.0
Density kg m-3
Summation Factor
at 288.15 K, kPa -1
Volume *
at 288.15 K, 101.325 kPa(abs)
Liquid, cm3 mol-1
Ratio, ideal gas/liquid
Critical Conditions
Temperature, K
Pressure, kPa(abs)
Gross Heating Value *
at 288.15 K, ideal reaction
MJ kg-1, fuel as liquid
MJ m-3, fuel as liquid
MJ kg-1, fuel as ideal gas
MJ m-3, fuel as ideal gas
Net Heating Value
at 288.15 K, ideal reaction
MJ m-3, fuel as ideal gas
Volume of Air to Burn One
Volume of Ideal Gas
Heat of Vaporization *
at 101.325 kPa(abs)
kJ kg-1 at the boiling point
Specific Heat *
--```,`,``,`,,`,,,``,,`,,```,,``-`-`,,`,,`,`,,`---
at 288.15 K, 101.325 kPa(abs)
C P , kJ kg-1 K-1, ideal gas
C V , kJ kg-1 K-1, ideal gas
k = C P /C V , ideal gas
C S , kJ kg-1 K-1, sat. liq.
Flammability Limits
at 310.93 K, 101.325 kPa(abs)
Lower, volume % In air
Upper, volume % in air
Octane Number
Motor clear
Research clear
* For some compounds, values within this property group are for conditions different from those given in the row heading. See the notes
on pages 12 through 14 for details. Values in boldface type are different from those in the previous version of GPA-2145.
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PHYSICAL PROPERTIES OF SELECTED HYDROCARBONS
GPA STANDARD 2145-09 (SI) becomes effective January 1, 2009
Component
Molar Mass
Boiling Temperature *
at 101.325 kPa(abs), K
n-Hexane
n-Heptane
n-Octane
n-Nonane
n-Decane
Ethylene
Propylene
86.1754
100.2019
114.2285
128.2551
142.2817
28.0532
42.0797
341.86
371.53
398.77
423.91
447.27
169.38
225.53
177.83
182.55
216.37
219.70
243.50
103.99
87.95
37.292
12.326
4.1263
1.414
0.4867
1648.5
0.66452
663.92
0.68864
688.02
0.70693
706.30
0.72262
721.97
0.73496
734.30
0.52346
522.99
2.9754
3.6446
3.4597
4.2378
3.9440
4.8310
4.4283
5.4242
4.9126
6.0174
0.9686
1.1864
1.4529
1.7797
0.0296
0.0364
0.0431
0.0500
0.0595
0.0079
0.0125
129.80
182.17
145.64
162.35
161.73
146.20
177.65
133.10
193.77
122.03
507.50
3012
540.13
2736
568.83
2487
594.6
2281
617.7
2103
48.342
32095
48.715
177.55
48.103
33096
48.474
205.42
47.919
33845
48.290
233.29
47.784
34498
48.152
261.19
164.39
190.39
216.38
45.355
52.516
334.9
Triple Point Temperature
K
Vapor Pressure *
at 313.15 K, kPa(abs)
Density of Liquid *
at 288.15 K, 101.325 kPa(abs)
Relative density at 15 °C/15 °C
Absolute density, kg m-3
Density of Ideal Gas
at 288.15 K, 101.325 kPa(abs)
Relative density, air = 1.0
Density kg m-3
Summation Factor
at 288.15 K, kPa -1
Volume *
at 288.15 K, 101.325 kPa(abs)
Liquid, cm3 mol-1
Ratio, ideal gas/liquid
80.46
293.9
Critical Conditions
Temperature, K
Pressure, kPa(abs)
282.35
5042
364.21
4555
47.671
35004
48.037
289.06
50.337
59.721
48.557
25395
48.941
87.097
242.40
268.39
55.96
81.46
59.677
66.839
74.000
14.323
21.484
316.9
302.2
288.6
276.4
482.4
439.0
1.6125
1.5160
1.0636
2.2104
1.6057
1.5227
1.0545
2.2038
1.6008
1.5280
1.0476
2.1918
1.5967
1.5319
1.0423
2.1719
1.5938
1.5354
1.0381
2.1562
1.4941
1.1977
1.2475
1.4916
1.2940
1.1527
2.5161
1.1
7.7
1.0
7.0
0.8
6.5
0.7
5.6
0.7
5.4
2.9
32.0
2.1
11.1
Gross Heating Value *
at 288.15 K, ideal reaction
MJ kg-1, fuel as liquid
MJ m-3, fuel as liquid
MJ kg-1, fuel as ideal gas
MJ m-3, fuel as ideal gas
Net Heating Value
--```,`,``,`,,`,,,``,,`,,```,,``-`-`,,`,,`,`,,`---
at 288.15 K, ideal reaction
MJ m-3, fuel as ideal gas
Volume of Air to Burn One
Volume of Ideal Gas
Heat of Vaporization *
at 101.325 kPa(abs)
kJ kg-1 at the boiling point
Specific Heat *
at 288.15 K, 101.325 kPa(abs)
C P , kJ kg-1 K-1, ideal gas
C V , kJ kg-1 K-1, ideal gas
k = C P /C V , ideal gas
C S , kJ kg-1 K-1, sat. liq.
Flammability Limits
at 310.93 K, 101.325 kPa(abs)
Lower, volume % In air
Upper, volume % in air
Octane Number
Motor clear
Research clear
26
24.8
All values in this table are on the International Temperature Scale 1990 (ITS-90).
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PHYSICAL PROPERTIES OF SELECTED HYDROCARBONS
GPA STANDARD 2145-09 (SI) becomes effective January 1, 2009
Component
Molar Mass
Boiling Temperature *
at 101.325 kPa(abs), K
Carbon
Dioxide
44.0095
Hydrogen
Sulfide
34.0809
194.69
216.59
Nitrogen
Oxygen
Helium
Air
Water
28.0134
31.9988
4.0026
28.9625
18.0153
212.85
77.355
90.188
4.230
78.90
373.12
187.70
63.151
54.361
2.177
59.75
273.16
Triple Point Temperature
K
Vapor Pressure *
7.3849
2863
at 313.15 K, kPa(abs)
Density of Liquid *
at 288.15 K, 101.325 kPa(abs)
Relative density at 15 °C/15 °C
Absolute density, kg m-3
0.82195
821.2
0.8001
799.4
0.80680
806.1
1.1422
1141.2
0.1248
124.7
0.87579
875.0
1.0000
999.102
1.5195
1.8613
1.1767
1.4414
0.9672
1.1848
1.1048
1.3533
0.1382
0.1693
1.0000
1.2249
0.62202
0.76191
0.00745
0.00913
0.00170
0.00275
0.00206
0.02495
53.59
441.2
42.63
554.6
34.753
680.4
28.040
843.3
32.089
736.9
33.10
714.3
18.031
1311.3
304.1
7377
373.1
9000
126.19
3396
154.58
5043
5.195
227.46
132.53
3786.0
647.10
22064
Density of Ideal Gas
at 288.15 K, 101.325 kPa(abs)
Relative density, air = 1.0
Density kg m-3
Volume *
at 288.15 K, 101.325 kPa(abs)
Liquid, cm3 mol-1
Ratio, ideal gas/liquid
Critical Conditions
Temperature, K
Pressure, kPa(abs)
Gross Heating Value *
at 288.15 K, ideal reaction
MJ kg-1, fuel as liquid
MJ m-3, fuel as liquid
MJ kg-1, fuel as ideal gas
MJ m-3, fuel as ideal gas
16.031
12815
16.501
23.784
2.4662
1.8790
Net Heating Value
at 288.15 K, ideal reaction
MJ m-3, fuel as ideal gas
21.905
Volume of Air to Burn One
Volume of Ideal Gas
Heat of Vaporization *
at 101.325 kPa(abs)
kJ kg-1 at the boiling point
7.161
573.3
546.4
199.2
213.1
20.75
204.9
2256.5
0.8334
0.6445
1.2931
2.8376
0.9976
0.7536
1.3237
2.1277
1.0395
0.7427
1.3996
0.9166
0.6568
1.3956
5.1931
3.1158
1.6667
1.0045
0.7174
1.4002
1.8620
1.4005
1.3295
4.1888
Specific Heat *
at 288.15 K, 101.325 kPa(abs)
C P , kJ kg-1 K-1, ideal gas
C V , kJ kg-1 K-1, ideal gas
k = C P /C V , ideal gas
C S , kJ kg-1 K-1, sat. liq.
Flammability Limits
at 310.93 K, 101.325 kPa(abs)
Lower, volume % In air
Upper, volume % in air
4.3
45.5
Octane Number
Motor clear
Research clear
* For some compounds, values within this property group are for conditions different from those given in the row heading. See the notes
on pages 12 through 14 for details. Values in boldface type are different from those in the previous version of GPA-2145.
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Summation Factor
at 288.15 K, kPa -1
TABLE FOR NOTES AND REFERENCES
GPA STANDARD
Component
C1
C2
2
b
b
2
2
b
b
All
Molar Mass
Boiling Temperature
1
at 101.325 kPa(abs), K
2
C3
i-C4
n-C4
i-C5
n-C5
n-C6
n-C7
d
d
d
d
b
b
d
d
d
d
d
d
d
d
2
2
2
2
2
2
2
2
2
2
2
2
2
2
3
3
2
2
3
d
d
3
d
d
3
d
d
3
d
d
3
3
3
3
3
l
l, m
l, m
l, m
m
m
Triple Point Temperature
2
K
Vapor Pressure
at 313.15 K, kPa(abs)
Density of Liquid
at 288.15 K, 101.325 kPa(abs)
Relative density at 15 °C/15 °C
Absolute density, kg m-3
Density of Ideal Gas
at 288.15 K, 101.325 kPa(abs)
Relative density, air = 1.0
Density kg m-3
f
Summation Factor
at 288.15 K, kPa -1
2
Volume
at 288.15 K, 101.325 kPa(abs)
Liquid, cm3 mol-1
Ratio, ideal gas/liquid
g
g
Critical Conditions
--```,`,``,`,,`,,,``,,`,,```,,``-`-`,,`,,`,`,,`---
Temperature, K
Pressure, kPa(abs)
Gross Heating Value
at 288.15 K, ideal reaction
MJ kg-1, fuel as liquid
MJ m-3, fuel as liquid
MJ kg-1, fuel as ideal gas
MJ m-3, fuel as ideal gas
i
g
Net Heating Value
at 288.15 K, ideal reaction
MJ m-3, fuel as ideal gas
Volume of Air to Burn One
Volume of Ideal Gas
Heat of Vaporization
at 101.325 kPa(abs)
kJ kg-1 at the boiling point
k
2
Specific Heat
at 288.15 K, 101.325 kPa(abs)
C P , kJ kg-1 K-1, ideal gas
C V , kJ kg-1 K-1, ideal gas
k = C P /C V , ideal gas
C S , kJ kg-1 K-1, sat. liq.
2
2
c
Flammability Limits
at 310.93 K, 101.325 kPa(abs)
Lower, volume % In air
Upper, volume % in air
4
4
Octane Number
Motor clear
Research clear
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m
m
2145-09 (SI)
n-C8
n-C9
n-C10
C 2=
C3 =
CO2
H2S
N2
O2
He
Air
H2O
a
c
c
c
d
c
c
3
3
2
2
2
2
2
2
2
2
3
3
3
c
c
3
d
d
3
c
c
c
c
d
d
d, e
d, e
d, e
d, e
d
d
d
d
h
h
h
h
h
h
h
h
2
2
2
2
2
2
2
2
2
2
2
2
d
d
3
j
j
n
c
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c
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c
c
c
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c
Molar Mass of Dry Atmospheric Air (g)
Component
Mole Fraction (x i)
nitrogen
0.78102
0.20946
oxygen
argon
0.00916
carbon dioxide
0.00033
neon
0.0000182
0.0000052
helium
methane
0.0000015
0.0000011
krypton
0.0000005
hydrogen
nitrous oxide
0.0000003
carbon monoxide
0.0000002
0.0000001
xenon
AIR
Molar Mass (M )
28.0134
31.9988
39.948
44.0095
20.1797
4.0026
16.0425
83.798
2.01588
44.0128
28.0101
131.293
x i·M
21.87903
6.70247
0.365924
0.014523
0.000367
0.000021
0.000024
0.000092
0.000001
0.000013
0.000006
0.000013
28.9625
b Shaded values were estimated by GPA for the hypothetical liquid state, and were not reevaluated in this revision of GPA-2145.
c The referenced temperature is above the critical temperature.
d The property is that of the liquid component at saturation pressure rather than at 101.325
e kDensities of liquid at the normal boiling temperature
f Gas constant R = 8.314472 J mol-1 K-1
g Algebraically derived from the absolute density of the liquid
h Gas at T = 288.15 K and liquid at the normal boiling point
i The basis for gross heating value is dry gas at T = 288.15 K and p = 101.325 kPa based
upon the ideal reaction. See GPA 2172 for conversion to other bases. Conversion of
enthalpies of combustion at T = 298.15 K from reference 3 were converted to the conditions
specified here with the property values from reference 2. Heating values for H2S are based on
SO2(g) and H2O as products.
j Enthalpy of vaporization to the ideal-gas state
k Values are based on an oxygen mole fraction of 0.20946 for air.
l The + sign and number specify the number of cm3 of TEL (tetraethyl lead) added per gallon
to achieve the ASTM octane number of 100, corresponding to that of 2,2,4-trimethylpentane.
m Average value from octane numbers using more than one sample
n Enthalpy of sublimation
o For components not listed in GPA-2145, the property values listed in TP-17 may be used.
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NOTES FOR GPA STANDARD 2145-08 (SI)
a The Molar Mass of Air is fixed by GPA to be 28.9625 in order to harmonize with ISO 697695, 'Natural gas -- Calculation of calorific value, density, relative density and Wobbe index
from composition' and AGA 5-07, 'Fuel Gas Energy Metering'. Individual components in Air
may change over time based on empirical data but the Molar Mass of Air, calculated from
the table shown below, will remain constant within this document for the purposes of, but
not limited to, the calculation of Gas Relative Density. The information in the table below
should not be used for individual component calculations. For information on individual
components refer to the appropriate Component Data Table. AGA 5-07 TABLE 7.17.1
follows.
References
1
M.E. Wieser, Pure Appl. Chem., 78, 2051-2066, 2006. All molar masses are listed with 4
decimal places without consideration of their uncertainties past the third decimal point.
2
E.W. Lemmon, M.L. Huber, and M.O. McLinden, Reference Fluid and Thermodynamic
and Transport Properties (REFPROP), NIST Standard Reference Database 23 (Version 8,
2007). NIST Standard Reference Data Program, Gaithersburg, MD. This database includes
the "The IAPWS Formulation 1995 for the Thermodynamic Properties of Ordinary Water
Substance for General and Scientific Use," J. Phys. Chem. Ref. Data , 31(2), 387-535,
2002.
3
A.F. Kazakov, C.D. Muzny, R.D. Chirico, V. Diky, R.A. Stevenson, and M. Frenkel,
NIST/TRC Web Thermo Tables (WTT) - Professional Edition, NIST Standard Reference
Subscription Database 3 (Version 1, 2007). NIST Standard Reference Data Program,
Gaithersburg, MD.
The critically evaluated enthalpies of combustion from WTT are all for T = 298.15 K with
liquid water as a product, in accord with how the values are determined experimentally.
Enthalpies of combustion for the hydrocarbon gases are based upon the following general
reaction:
--```,`,``,`,,`,,,``,,`,,```,,``-`-`,,`,,`,`,,`---
Hydrocarbon(gas) + oxygen(gas) = carbon dioxide(gas) + water(liquid)
Values (in J/g of hydrocarbon) used to derive the quantities listed in GPA-2145 are:
methane (-55517), ethane (-51903), propane (-50325), i-butane (-49347),
n-butane (-49505), ethylene (-50303), and propylene (-48907).
Enthalpies of combustion for the hydrocarbon liquids are based upon the following general
reaction:
Hydrocarbon(liquid) + oxygen(gas) = carbon dioxide(gas) + water(liquid)
Values (in J/g of hydrocarbon) used to derive the quantities listed in GPA-2145 are:
i-pentane (-48560), n-pentane (-48635), n-hexane (-48310), n-heptane (-48071),
n-octane (-47888), n-nonane (-47753), and n-decane (-47640).
The enthalpy of combustion for hydrogen sulfide is based upon the following reaction:
Hydrogen sulfide(gas) + 1.5 oxygen(gas) = sulfur dioxide(gas) + water(liquid)
The value (in J/g of hydrogen sulfide) is -16490.5.
4
Engineering Sciences Data Unit, "Fire Hazard Properties: Flash Points, Flammability
Limits and Autoignition Temperatures," ESDU 82030, September 1983.
5
E.F. Obert, "Internal Combustion Engines and Air Pollution," Harper & Row: NewYork,
1973.
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