MIL-HDBK-1022A
10.2.2
General Design Considerations. LPG is odorless,
colorless, non-toxic, heavier than air, and explosive. To
permit easier leak detection, an artificial odor may be
introduced when shipped from a refinery. Under standard
atmospheric conditions, LPG is in a vapor phase, but it is
liquefied under moderate pressure for shipping and storage.
The maximum vapor pressure for LPG design is 215 psig (1480
kPa) at 100 degrees F (38 degrees C). All LPG purchased by
the military should emit a distinct odor at a concentration
required by NFPA 58. See Facility Plate Nos. 030 through 033.
10.2.2.1 Fire Hazards. In the vapor phase, LPG is a hazard
comparable to flammable natural or manufactured gas. The
explosive range is 2.16 to 9.6 percent by volume of air-gas
mixture.
a) Provide ventilation in accordance with NFPA 58.
b) In the liquid phase, LPG is a highly volatile,
flammable liquid. Because of rapid vaporization, an LPG fire
is basically a gas fire. Therefore, in the event of a fire,
provide means to automatically shut off the LPG supply feeding
the fire.
c) Provide emergency shut-off consisting of the
combination of three modes: manual shut-off, remote shut-off,
and thermal shut-off. Remote shut-off normally consists of a
nitrogen system with plastic tubing at the controlled point so
that the pressure holds open the valve. The plastic tubing
acts as a fusible link. Provide a cable release shut-off with
remote shut-off for combination shut-off. Refer to MIL-HDBK-
1027/1 and API Std 2510.
d) Provide leak detection in accordance with NFPA
59.
e) For LPG equipment located inside buildings where
there is a potential for loss of LPG, provide an
alarm/detection system with local and remote alarms (audible
and visual), high and low ventilation, doors with panic
hardware, a leak detector readout with the readout outside,
and a leak detector kit located outside.
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