3.4.1 Standard parts. MS and AN standard parts shall be used where they
suit the purpose. When MS or AN standard parts are used, they shall be oxygen
3.4.2 Metal parts. All metal parts shall be of a corrosion resistant
material or treated in a manner to render them adequately resistant to corrosion.
184.108.40.206 Dissimilar metals. Unless suitably protected against electrolytic
corrosion, dissimilar metals shall not be used in intimate contact with each
other. Dissimilar metals are defined in MIL-STD-889.
220.127.116.11 Finish. Aluminum and aluminum alloy parts shall be protected in
accordance with MIL-A-8625 or MIL-C-5541.
3.4.3 Elastomer parts. Any elastomer part that is adversely affected by
continued use with oxygen shall not be used.
18.104.22.168 Age. Elastomer parts except silicone shall be not more than 12
months old from the date of manufacture to the date of delivery to any Government
service or to any airframe or accessory manufacturer.
22.214.171.124 Ozone resistance. The elastomer parts shall be composed of ozone
resistant materials, which shall not bloom, and shall meet the specified ozone
resistance performance requirements.
126.96.36.199 Storage life. Elastomeric materials selected shall have an expected
shelf storage life of 8 years or more based on the guidelines of MIL-HDBK-695
when such materials will provide the required physical, mechanical, and chemical
3.4.4 Organic parts. All organic parts, regardless of state or
modification, used in the regulator construction shall not support fungoid
growth, as defined in MIL-STD-810, Method 508.
3.4.5 Protective treatment. When materials used in the construction of the
regulator are subject to deterioration when exposed to environmental conditions
likely to occur during service usage, they shall be protected against such
deterioration in a manner that shall in no way prevent compliance with the
performance requirements of this specification. Protective coating which might
crack, chip or scale during normal service life or under extremes of
environmental conditions shall not be used.
3.4.6 Adhesives. The regulator shall not contain glue, varnish or other
such coatings or adhesives to secure parts (except labels) or to seal leaks.
188.8.131.52 Degreasing. Prior to assembling the regulator and its
subassemblies, all internal surfaces shall be degreased in accordance with MIL-
184.108.40.206 Lubricants. Lubricants qualified to MIL-G-27617 may be used
sparingly on seals and straight threads if assembly difficulty is encountered.
3.4.8 Toxic materials. Materials that produce toxic or corrosive substances
shall not be used in the construction of the regulator.