UFC 4-390-01
23 July 2003
B.8.2.1.4 Filters. Compressor outlet filters are to be located
downstream of the moisture separator and backpressure regulator
and upstream of the rest of the system. All installed filter
housings (except compressor inlet housings) should be
hydrostatically tested. The periodicity for hydrostatic testing
should be negotiated with the SCA. Depending on system design,
additional particulate filters may be required to protect
sensitive system components.
Components should have a working pressure that is greater than
the maximum system pressure and the purification chambers should
conform to ASME Code for unfired pressure vessels, Section VIII,
Division 1.
B.8.2.1.5 Valves. For guidance on the selection of valves for a
particular application refer to MIL-STD-777, NSTM Chapter 505,
ASME B31.1 or NAVFAC DM-39.
Valves utilizing a soft seat design are preferable to those
employing a metal-to-metal seat design.
Periodic inspection and maintenance should be performed in
accordance with PMS. Pressure boundary hydrostatic and seat
tightness testing of valves should be in accordance with NSTM
Chapter 505.
B.8.2.1.6 Receivers and Volume Tanks. All air systems that are
supplied air from a compressor should incorporate medium or low-
pressure receivers or volume tanks. These components help to
eliminate pulsations in the compressor discharge, and act as
storage tanks, allowing the compressor to shut down during
periods of light load. Receivers and volume tanks should be
fabricated using approved specifications for pressure vessels
described in Section B-5.1. In general, receivers and volume
tanks are fabricated in accordance with Section VIII of the ASME
Boiler and Pressure Vessel Code. All receivers and volume tanks
should be equipped with pressure gages, drain valves and relief
valves. Receivers and volume tanks should be inspected in
accordance with MIL-HDBK-1152, Inspection and Certification of
Boilers and Unfired Pressure Vessels. More information on
receivers and volume tanks can be found in NSTM Chapter 551.
B.8.2.1.7 Flasks. If high-pressure gas cylinders or flasks are
installed, they should be designed and fabricated in accordance
with DOD-approved specifications such as MIL-F-22606, Flask
Compressed Gas and End Plugs for Air, Oxygen and Nitrogen or
standards of DOT or ASME. Each gas flask should have a readily
accessible isolation valve to stop gas flow to the system. The
flask isolation valve must be able to withstand full flask
pressure. Each air flask should incorporate a method for
periodically draining moisture from its interior (i.e., drain
valve, dip tube). MIL-F-22606 system air/gas flasks should be
periodically inspected and undergo either nondestructive testing
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