LPG Data

THEORETICAL COMPATIBLE PROPANE/AIR MIXTURES

The table below shows Propane/Air mixtures, compatible with natural gas with several different specific gravities and calorific values.
All figures are approximate and are given for Propane with specific gravity of 1.53 and calorific value of 2516 BTU/cuft.

Natural Gas		Propane / Air Mixture
SGU	BTU/cuft	% LPG	% Air	SGU	BTU/cuft
0.56	800	47.54	52.46	1.252	1196
	850	50.87	49.13	1.270	1280
	900	54.24	45.76	1.287	1365
	950	57.65	42.35	1.306	1450
	1000	61.11	38.89	1.324	1538
	1050	64.62	35.38	1.342	1626
	1100	68.16	31.84	1.361	1715
	1150	71.76	28.24	1.380	1805
	1200	75.40	24.60	1.400	1897
0.58	800	46.62	53.38	1.247	1173
	850	49.88	50.12	1.264	1254
	900	53.18	46.82	1.282	1338
	950	56.52	43.48	1.300	1422
	1000	59.90	40.10	1.317	1507
	1050	63.33	36.67	1.336	1593
	1100	66.80	33.20	1.354	1681
	1150	70.32	29.68	1.373	1769
	1200	73.88	26.12	1.392	1859
0.60	800	45.76	54.24	1.243	1151
	850	48.95	51.05	1.259	1232
	900	52.18	47.82	1.276	1313
	950	55.45	44.55	1.294	1395
	1000	58.76	41.24	1.311	1478
	1050	62.12	37.88	1.329	1563
	1100	65.51	34.49	1.347	1648
	1150	68.95	31.05	1.365	1735
	1200	72.43	27.57	1.384	1822

Natural Gas		Propane / Air Mixture
SGU	BTU/cuft	% LPG	% Air	SGU	BTU/cuft
0.62	800	44.93	55.07	1.238	1130
	850	48.06	51.94	1.255	1209
	900	51.23	48.77	1.272	1289
	950	54.43	45.57	1.288	1369
	1000	57.68	42.32	1.306	1451
	1050	60.97	39.03	1.323	1534
	1100	64.29	35.71	1.341	1618
	1150	67.66	32.34	1.359	1702
	1200	71.07	28.93	1.377	1788
0.64	800	44.15	55.85	1.234	1111
	850	47.22	52.78	1.250	1188
	900	50.32	49.68	1.267	1266
	950	53.47	46.53	1.283	1345
	1000	56.65	43.35	1.300	1425
	1050	59.87	40.13	1.317	1506
	1100	63.13	36.87	1.335	1588
	1150	66.44	33.56	1.352	1672
	1200	69.78	30.22	1.370	1756
0.66	800	43.41	56.59	1.230	1092
	850	46.42	53.58	1.246	1168
	900	49.47	50.53	1.262	1245
	950	52.55	47.45	1.262	1322
	1000	55.68	44.32	1.295	1401
	1050	58.84	41.16	1.312	1480
	1100	62.04	37.96	1.329	1561
	1150	65.27	34.73	1.346	1642
	1200	68.55	31.45	1.363	1725

Properties of		Natural Gas	Propane	Butane
Chemical formula		CH₄	C₃H₈	C₄H₁₀
Boiling point of liquid at atmospheric pressure	°F °C	-259 -162	-44 -42	32 0
Specific Gravity of vapor (Air = 1)		0.6	1.53	2.00
Specific Gravity of liquid (Water = 1)		0.6	0.51	0.58
Calorific value @ 60 °F (15°C)	BTU/cuft kcal/m³	1012 9005	2516 22,390	3280 29,190
	BTU/gal kcal/liter		91,690 6,100	102,032 6,790
	BTU/lb kcal/kg		21,591 11,995	21,221 11,790
Latent heat of vaporization	BTU/gal kcal/kg		785	808
Liquid weight	lbs/gal kg/liter		4.24 0.508	4.81 0.576
Vapor volume from 1 gallon of liquid at 60 °F Vapor volume from 1 liter of liquid at 15 °C	cuft m³		36.39 0.272	31.26 0.234
Vapor volume from 1 lb. of liquid at 60 °F Vapor volume from 1 kg of liquid at 15 °C	cuft m³		8.547 0.534	6.506 0.406
Combustible limits	% of gas in air	5 - 15	2.4 - 9.6	1.9 - 8.6
Amount of air required to burn 1 cuft. of gas Amount of air required to burn 1 m³ of gas	cuft m³	9.53	23.86	31.02
Ignition temperature in air	°F °C	1200 650	920 - 1020 490 - 550	900 - 1000 480 - 540
Maximum flame temperature in air	°F °C	3568 1964	3595 1980	3615 1991
Octane Number		100	Over 100	92
All data is approximate. For actual properties of any particular batch, contact your fuel supplier.

Approximate Vapor Pressure in psig
Temperature		Propane ----> To ----> Butane
° F	° C	100%	95/5*	80/20	60/40	50/50	40/60	20/80	100%
-40	-40.0	3.6	1.3
-30	-34.4	8	5.5	4.5
-20	-28.9	14	11	9.2	4.9	1.9
-10	-23.3	20	17	16	9	6	3.5
0	-17.8	28	24	22	15	11	7.3
10	-12.2	37	32	29	20	17	13	3.4
20	-6.7	47	41	36	28	23	18	7.4
30	-1.1	58	52	45	35	29	24	13
40	4.4	72	63	58	44	37	32	18	3
50	10.0	86	77	69	53	46	40	24	6.9
60	15.6	102	93	80	65	56	49	30	12
70	21.1	127	109	95	78	68	59	38	17
80	26.7	140	128	125	90	80	70	46	23
90	32.2	165	149	140	112	95	82	56	29
100	37.8	196	172	168	137	123	100	69	36
110	43.3	220	197	185	165	148	130	80	45
* HD5, Commercial Grade Propane

Temperature Conversion Table

°F

°C

- 50

- 45.6

- 40

- 40.0

- 30

- 34.1

- 20

- 28.9

- 10

- 23.3

- 17.8

+ 10

- 12.2

- 6.7

- 1.1

+ 4.4

10.0

15.6

21.1

26.7

32.2

100

37.8

110

43.3

120

48.9

130

54.4

140

60.0

150

65.6

160

71.1

170

76.7

180

82.2

190

87.8

200

93.3

212

100

Formula:

Degrees C = (°F - 32) x 5/9
Degrees F = 9/5 x °C + 32

BTU content of common fuels
	Per Pound	Per Gallon
Propane	21,591	91,690
Butane	21,221	102,032
Gasoline	20,930	110,250
Fuel Oil #1	16,960	135,425
Diesel	18,500	142,800

Butane Equivalents
Unit	BTU	Pound	Therm	Dekatherm	Cuft.	Gallon
1 Pound =	21,221	1	0.212	0.0212	6.50	0.208
1 Therm =	100,000	4.714	1	0.1	30.64	0.98
1 Dekatherm =	1,000,000	47.14	10	1	306.4	9.8
1 Cuft. =	3,280	0.1537	0.032	0.0032	1	0.03199
1 Gallon =	102,032	4.81	1.02	0.1020	31.26	1

General Information
1 Lb. Steam	970 BTU
1 Boiler HP (per hr)	33,475 BTU
1 Kilowatt Hour	3,412 BTU
1 Gallon, Water	8.337 lbs
1 Cubic Foot, Water	7.481 gallons
1 Cubic Foot	1,728 cubic inches
1 Gallon	231 cubic inches

Propane Equivalents
Unit	BTU	Pound	Therm	Dekatherm	Cuft.	Gallon
1 Pound =	21,591	1	0.216	0.0216	8.58	0.239
1 Therm =	100,000	4.622	1	0.1	39.7	1.10
1 Dekatherm =	1,000,000	46.22	10	1	397	11.0
1 Cuft. =	2,516	0.1164	0.025	0.0025	1	0.027
1 Gallon =	91,690	4.24	0.917	0.0917	36.39	1

Specific Gravity and Heat Content by Volume of LP Gas-Air Mixtures

Propane - Air Mixtures
% Propane	% Air	Specific Gravity	Gross BTU/cuft
100	0	1.530	2516
95	5	1.504	2390
90	10	1.477	2264
85	15	1.451	2139
80	20	1.424	2013
75	25	1.398	1887
70	30	1.371	1761
65	35	1.345	1635
60	40	1.318	1510
59	41	1.313	1484
58	42	1.307	1459
57	43	1.302	1434
56	44	1.297	1409
55	45	1.292	1384
54	46	1.286	1359
53	47	1.281	1333
52	48	1.276	1308
51	49	1.270	1283
50	50	1.265	1258
49	51	1.260	1233