13
fuel Pipe sizing
There are numerous on-line or otherwise-published
references for fuel pipe sizing. For example, NFPA 54 -
National 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.
• A manual fuel shut-off valve located in the interior of
the building.
• Where local conditions include earthquake,
tornado, unstable ground, or flood hazards, special
consideration shall be given to increase strength and
flexibility of piping supports and connections.
• Piping must be of the correct size to maintain the
required supply pressures and volume flow under
varying generator load conditions with all gas
appliances connected to the fuel system turned on
and operating.
• Use a pipe sealant or joint compound approved for
use with NG/LPG on all threaded fittings to reduce the
possibility of leakage.
• Installed piping must be properly purged and
leak tested, in accordance with applicable codes
and standards.
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.
Maximum pressure with engine OFF at No Load is 13.85 psi.
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 m) above sea level and 1% for each
10° F (5.6°C) above 77°F (25°C). Generators located in these
conditions must have their transfer switch programmed
appropriately for this power decrease.
Not
for
Reproduction
