Physical Properties Quick Reference

Density, viscosity, specific heat, and thermal conductivity for common process fluids and utilities.

Hydrocarbons

Hydrocarbon Physical Properties

Compound	Formula	MW (g/mol)	NBP (°F)	SG (60°F/60°F)	Liquid Cp (BTU/lb·°F)	Hv @ NBP (BTU/lb)	API Gravity	Auto-Ignition (°F)
Methane	CH4	16.04	-258.7	0.3	0.526	219	—	999
Ethane	C2H6	30.07	-127.5	0.356	0.41	210	—	882
Propane	C3H8	44.1	-43.7	0.507	0.388	184	—	842
n-Butane	nC4H10	58.12	31.1	0.584	0.382	166	110.6	761
i-Butane	iC4H10	58.12	10.9	0.563	0.387	157	119.3	864
n-Pentane	nC5H12	72.15	96.9	0.631	0.388	153	92.7	500
i-Pentane	iC5H12	72.15	82.1	0.624	0.385	147	95.5	788
n-Hexane	C6H14	86.18	155.7	0.664	0.386	144	81.1	437
n-Heptane	C7H16	100.2	209.2	0.688	0.386	136	72.6	419
n-Octane	C8H18	114.2	258.2	0.707	0.387	131	65.5	403
n-Nonane	C9H20	128.3	303.5	0.722	0.388	127	59.7	401
n-Decane	C10H22	142.3	345.5	0.734	0.39	123	55.1	410
Ethylene	C2H4	28.05	-154.7	0.34	0.37	207	—	842
Propylene	C3H6	42.08	-53.9	0.522	0.365	188	—	851
1-Butene	C4H8	56.11	20.8	0.6	0.37	167	—	725
Benzene	C6H6	78.11	176.2	0.884	0.267	169	28	928
Toluene	C7H8	92.14	231.1	0.872	0.264	156	31.1	896
Ethylbenzene	C8H10	106.2	277.2	0.871	0.269	147	31.4	810
o-Xylene	C8H10	106.2	291.9	0.884	0.268	149	28	867
p-Xylene	C8H10	106.2	281.1	0.866	0.268	147	32.6	867
Cyclopentane	C5H10	70.13	120.7	0.751	0.297	153	57.1	682
Cyclohexane	C6H12	84.16	177.3	0.783	0.299	153	49	473
Hydrogen	H2	2.016	-423	0.071	—	192	—	932
H2S	H2S	34.08	-76.5	0.79	0.243	234	—	500
CO2	CO2	44.01	-109.3	0.817	—	100	—	—
Nitrogen	N2	28.01	-320.4	0.808	—	86	—	—
Water	H2O	18.02	212	1	1	970	—	—

Common Gases

Common Gas Properties

Gas	Formula	MW	Tc (°F)	Pc (psia)	NHV (BTU/SCF)	GHV (BTU/SCF)	Gas Density (lb/ft³ @ STP)
Hydrogen	H2	2.016	-399.8	188	275	325	0.00531
Methane	CH4	16.04	-116.6	668	912	1012	0.0423
Ethane	C2H6	30.07	89.9	708	1630	1783	0.0793
Ethylene	C2H4	28.05	48.6	731	1513	1614	0.074
Propane	C3H8	44.1	206.2	617	2371	2573	0.1162
Propylene	C3H6	42.08	197.2	668	2185	2336	0.111
n-Butane	nC4H10	58.12	305.6	551	3113	3365	0.1532
i-Butane	iC4H10	58.12	274.4	529	3113	3365	0.1532
Carbon Monoxide	CO	28.01	-220.4	507	321	321	0.0739
Carbon Dioxide	CO2	44.01	87.8	1071	0	0	0.116
Hydrogen Sulfide	H2S	34.08	212.4	1300	596	647	0.0899
Nitrogen	N2	28.01	-232.5	492	0	0	0.0739
Oxygen	O2	32	-181.1	731	0	0	0.0843
Ammonia	NH3	17.03	270.1	1636	364	434	0.0449
Water Vapor	H2O	18.02	705.4	3206	0	0	0.0475

Water & Steam

Saturated Steam Properties

Pressure (psig)	Pressure (psia)	Sat Temp (°F)	Hf (BTU/lb)	Hfg (BTU/lb)	Hg (BTU/lb)	Specific Vol (ft³/lb)
0	14.696	212	180.2	970.3	1150.5	26.8
5	19.696	227.9	196.3	960	1156.3	20.39
10	24.696	239.4	208.5	952.1	1160.6	16.5
15	29.696	249.8	218.9	945.2	1164.1	13.88
25	39.696	266.8	236.1	933.6	1169.7	10.66
50	64.696	297.7	267.5	912	1179.5	6.75
75	89.696	320.3	290.6	894.8	1185.4	4.99
100	114.696	337.9	308.8	880	1188.8	3.89
125	139.696	352.6	324	867	1191	3.22
150	164.696	365.9	338.5	854.2	1192.7	2.75
200	214.696	387.8	361.9	834.3	1196.2	2.13
250	264.696	406	381.6	817.2	1198.8	1.74
300	314.696	421.7	398.4	802	1200.4	1.46
400	414.696	448.1	427.4	774.5	1201.9	1.1
500	514.696	470.1	452	749.8	1201.8	0.88
600	614.696	488.8	473.5	727.3	1200.8	0.73
750	764.696	510.9	499.8	698.8	1198.6	0.58
900	914.696	532	526.6	668.8	1195.4	0.47
1200	1214.7	567.2	571.5	616.8	1188.3	0.34
1500	1514.7	596.2	611.5	564	1175.5	0.26

Conversions

Unit Conversion Factors

From	To	Multiply By	Category
psi	kPa	6.8948	Pressure
psi	bar	0.06895	Pressure
psi	atm	0.06805	Pressure
atm	psi	14.696	Pressure
bar	psi	14.504	Pressure
inH2O	psi	0.03613	Pressure
inHg	psi	0.4912	Pressure
mmHg (torr)	psi	0.01934	Pressure
°F	°C	(°F-32)/1.8	Temperature
°C	°F	°C×1.8+32	Temperature
°F	°R	°F+459.67	Temperature
°C	K	°C+273.15	Temperature
GPM	m³/hr	0.2271	Flow
GPM	BPD	34.286	Flow
BPD	GPM	0.02917	Flow
BPD	m³/day	0.159	Flow
SCFM	Nm³/hr	1.589	Flow
lb/hr	kg/hr	0.4536	Flow
inch	mm	25.4	Length
ft	m	0.3048	Length
mile	km	1.6093	Length
lb	kg	0.4536	Mass
short ton	kg	907.2	Mass
long ton	kg	1016	Mass
metric ton	lb	2205	Mass
BTU	kJ	1.0551	Energy
BTU	kcal	0.252	Energy
HP	kW	0.7457	Energy
MMBTU/hr	MW	0.2931	Energy
BTU/lb	kJ/kg	2.326	Energy
US gallon	liter	3.7854	Volume
barrel (42 gal)	liter	158.99	Volume
ft³	m³	0.02832	Volume
ft³	gallon	7.4805	Volume

Constants

Engineering Constants & Standard Conditions

Constant	Value	Units	Notes
Universal Gas Constant (R)	1545	ft·lbf/(lbmol·°R)	Also: 10.73 psia·ft³/(lbmol·°R)
R (SI)	8.314	J/(mol·K)	Also: 8.314 kPa·L/(mol·K)
R (psia·ft³)	10.73	psia·ft³/(lbmol·°R)	PV=nRT form
Gravitational Constant (g)	32.174	ft/s²	Standard gravity
gc (gravitational conversion)	32.174	lbm·ft/(lbf·s²)
Standard Temperature	60	°F	API / petroleum standard
Standard Pressure	14.696	psia	1 atmosphere
Normal Temperature (SI)	32	°F (0°C)	IUPAC normal conditions
Normal Pressure (SI)	14.696	psia (101.325 kPa)
Molar Volume @ STP	379.5	SCF/lbmol	At 60°F, 14.696 psia
Molar Volume (SI)	22.414	L/mol @ NTP	At 0°C, 101.325 kPa
Water Density @ 60°F	62.37	lb/ft³
Water Density @ 60°F	8.337	lb/gal
Water Specific Gravity	1	@ 60°F/60°F	Reference
Speed of Sound in Air	1125	ft/s	At 68°F, 1 atm
Atmospheric Pressure	14.696	psia	At sea level
Atmospheric Pressure	29.92	inHg	At sea level
Atmospheric Pressure	407.2	inH2O	At sea level
Stefan-Boltzmann Constant	1.714e-09	BTU/(hr·ft²·°R⁴)	Radiation
Absolute Zero	-459.67	°F	0 °R
Pi (π)	3.14159
Euler's Number (e)	2.71828
API Gravity Formula	141.5/SG - 131.5		SG at 60°F/60°F
Barrel	42	US gallons	Petroleum barrel
Head to Pressure	2.31	ft H2O per psi	For SG=1.0 water

Source: Physical_Properties_Quick_Reference_v1.xlsx

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