Downloaded from https://www.everyspec.com MIL-STD-81OD 19 July 1983 during which the given temperature is equalled or surpassed. For example, the 20 percent probability of occurrence of a temperature of -51‘C means that”-51° C o or lower temperatures may be expected to occur 20 percent of the hours during the most extreme month in the most extreme cold area of the world (excluding Antarctica). -51OrJL/ (-GoOF) 20% -540c (-650F) 10% -570C (-710F) -610c (-780F) 1% The 20 percent probability of occurrence is used for most applications with normal development cost consideration; however, other values may be choeen to satisfy specific applications or test requirements.
(3) Liorldwideuse with extended s oraae oeriOd& t If materiel is to be stored for extended periods (years) without shelter or protection in areas that experience very low temperatures, such ae the “cold pole” of northeast Siberia or central Greenland, there is an increaeed chance that the test item may experience much lower temperature (approaching -650C.(-850F) or less). ,CSuch prolonged exposure to extreme low temperatures can affect the safety of items such as munitions, life support equipment, etC. b. of exDosure to lDW Le-atureti. The period of time that the low-temperature exposure exists may be a factor.
o (1) rdous or non-safetv-related (non llfeDoort tVDe~ Meet materiel in this category (in a nonoperating mode), with the possible exception of organic plastice (1-2h “and I-3.2b(2)), will not experience deterioration following temperature Stabilizatim of the test item at low temperatures. FDllOWing temperature stabilization of the test item, a storage period of 4 hours will be used for this materiel if no other value is available. (2) Explosives. mun1 DhS t. s. ate. These items may cmtinue to deteriorate following temperature stabilization; consequently, it is neceaaary to test them at lDW temperatures for 10ng periDdS Of time.
A minimum storage period of 72 hours is recommended, since extreme temperatures have existed for at least that length of time. ~ Y Corresponds to Severe Cold condition. METHOD 502.2 19 JUIY 1983 502.2-6