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.
comparable to flammable natural or manufactured gas. The
explosive range is 2.16 to 9.6 percent by volume of air-gas
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
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
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,