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1 CFH = 1000 BTU of Natural Gas
= 2000 BTU of LP/Propane
(when exposed to the environment) |
Note: The vent shall be designed to prevent entry of water, insects, or other foreign materials that could cause blockage. ANSI Z223.1/NFPA 54 5.8.5.1 C2 - 2006
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Note: 12A04, 12A09, and 12A39 Vent Limiting Devices (when used) must be installed directly into vent tapping of regulator, and regulator must be in normal horizontal position with the stack to the sky.
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| Note: Heating value specific gravity may vary based on location. Please contact local utility or gas suplier. |
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Pressure Equivalents
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1" water column |
= 0.036 lb per sq inch
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1" water column |
= 0.577 ounces per sq inch |
1" water column |
= 0.0737" mercury column |
| 1 lb per sq inch |
= 27.7" water column |
1 ounce per sq inch |
= 1.73" water column
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1" mercury column |
= 13.56" water column
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Conversion Factors - Cubic feet per hour (ft³/h)
Simple Conversions - use the conversion factors for standard fuel gases. |
multiply |
by |
to get |
0.64 sp gr GAS* |
0.800 |
1.0 sp gr AIR |
1.00 sp gr AIR |
1.25 |
0.64 sp gr GAS* |
1.53 sp gr GAS** |
1.55 |
0.64 sp gr GAS* |
0.64 sp gr GAS* |
0.645 |
1.53 sp gr GAS** |
1.53 sp gr GAS** |
1.24 |
1.0 sp gr AIR |
1.0 sp gr AIR |
0.807 |
1.53 sp gr GAS** |
Example |
The 325-5AL will flow 338 ft³/h of 0.64 sp gr NAT gas at pressure drop of 7.0" w.c. |
Question |
How many ft³/h of 1.53 LP gas will flow at the same pressure drop? |
Solution |
338 x 0.645 = 218 ft³/h LP gas |
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| British thermal units per hour (Btu/hr) |
multiply |
by |
to get |
1000 Btu, 0.64 sp gr GAS* |
0.515 |
500 Btu, 0.60 sp gr GAS |
500 Btu, 0.60 sp gr GAS |
1.94 |
1000 Btu, 0.64 sp gr GAS* |
1000 Btu, 0.64 sp gr GAS* |
1.61 |
2500 Btu, 1.53 sp gr GAS** |
Example |
The 325-3L will flow 145,000 Btu/hr of 0.64 sp gr, 1000 Btu/ft³ NAT gas at pressure drop of 7.0" w.c. |
Question |
How many Btu/hr of 1.53 sp gr, 250 Btu/ft³ LP gas will flow at the same pressure drop? |
Solution |
145,000 x 1.61 = 233,500 Btu/hr LP gas |
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* Natural Gas typically 1000 Btu/ft³, 0.64 sp gr
** LP Gas typically 2500 Btu/ft³, 1.53 sp gr
sp gr = specific gravity
(from Servicing a Gas Pressure Regulator - Maxitrol Bulletin GPR_MI_EN_11.2006) |
