Fuel Consumption; Natural Gas; Fuel Pressure; Power Loss - Briggs & Stratton 40336 Manual De Instalación

Fuel Consumption

Estimated fuel supply requirements at half and full load for
natural gas and LP vapor fuels are shown below.
20kW

Natural Gas

1/2 Load Full Load
160 C 215 C
160,000 B 215,000 B
C = Cubic feet per hour
B = BTU's per hour
16kW
Natural Gas
1/2 Load Full Load
145 C 186 C
145,000 B 186,000 B
C = Cubic feet per hour
B = BTU's per hour
15kW (California Only)
Natural Gas
1/2 Load Full Load
134 C 174 C
134,000 B 174,000 B
C = Cubic feet per hour
B = BTU's per hour
LP Vapor
1/2 Load Full Load
69 C 108 C
172,000 B 270,000 B
LP Vapor
1/2 Load Full Load
56 C 85 C
140,000 B 211,000 B
LP Vapor
1/2 Load Full Load
56 C 78 C
140,000 B 195,000 B
Physical Properties
Normal Atmospheric State
Boiling Point (in °F):
Initial
End
Heating Value:
BTU per gallon (Net LHV*)
BTU per gallon (gross**)
Cubic feet (gas)
Density***
Weight†
Octane Number:
Research
Motor
* LHV (Low Heat Value) is the more realistic rating.
** Gross heat value does not consider heat lost in the form of water
during combustion.
*** Density is given in "Cubic Feet of Gas per Gallon of Liquid".
† Weight is given in "Pounds per Gallon of Liquid".

Fuel Pressure

Both LP vapor and natural gas fuel supply pressure at the
generator's fuel inlet port should be between the following
levels at full load with all gas appliances turned on
and operating.
• NG is 5-7" W.C.
• LP is 11-14" W.C.
Ensure that all gas line shutoff valves are OPEN and that
adequate fuel pressure is available whenever automatic
operation is desired.

Power Loss

Air density is less at high altitudes, resulting in less available
engine power. Specifically, engine power will decrease 3.5%
for each 1,000 feet (300 meters) above sea level and 1% for
each 10° F (5.6°C) above 77°F (25°C). Make sure you and
your installer consider these factors when determining total
generator load.

Fuel Pipe Sizing

There are numerous on-line or otherwise-published
references for fuel pip sizing. For example, NFPA 54-Natural
Fuel Gas Code, 2006 (Item #: 320-6031-06) is a
common resource.
The installer should consider the specific gravity of gas and
compensate for a nominal amount of restriction from bends,
fittings, etc. If an unusual number of fittings, bends, or other
restrictions are used, refer to federal and local codes
for guidance.
LP Vapor Natural
Gas
Gas Gas
-44 -259
-44 -259
83,340 63,310
91,547
2,500 1,000
36.39 57.75
4.24 2.65
110+ 110+
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