JOTP-011
5 December 2014
APPENDIX A. BACKGROUND/RATIONALE
ANNEX 1. ENVIRONMENTAL TESTS
are likely such as those related to constant strain at cold temperatures, then longer durations may
be required and guidance should be sought from the munition designer. If the munition under test
could be susceptible to thermo-mechanical stresses due to low temperature fluctuations, the C2
low temperature cycle or that defined in the LCEP should be used.
The low-temperature cycling test is intended to determine the effects of low-temperature
operational environments on the munition (storage at extreme cold is addressed by the cold
temperature storage test). The temperatures associated with the low-temperature cycling test are
created by meteorological air temperatures (note that at this temperature extreme, the
meteorological and induced diurnal cycles become aligned). The induced air temperature diurnal
cycle (C2) for Category C storage and transit conditions given in MIL-STD-810, Method 502 is
considered to adequately encompass most conceivable situations.
A.1-2.2.2 High Temperature Storage and Cycling (Appendix C, Annex 1, Paragraphs C.1-3 and
C.1-4).
The high temperature cycling test is intended to determine the effects of thermo-mechanical
stresses on the munition. The induced air temperature diurnal cycle for Category A1 storage and
transit conditions given in MIL-STD-810 Method 501 is considered to adequately encompass most
conceivable situations. For other environments, such as Naval controlled environments, other
storage categories may be considered and are LCEP dependent.
The high temperature storage test is intended to accelerate chemical and physical based
degradation mechanisms via a period of testing using a constant elevated temperature. A constant
temperature of +71 °C is the maximum temperature that should be considered since this reflects
the peak temperatures likely to be encountered during field storage or deployment in an A1 climate
zone. Alternatively, a constant temperature of +58 °C may be more appropriate where the use of
+71 °C is thought to generate unrealistic degradation.
For most munitions, 28 hot A1 induced diurnal cycles are considered sufficient to induce thermo-
mechanical stressing representative of that which could occur in service. For chemical and/or
physical ageing processes (e.g., stabilizer depletion or diffusion of chemical substances) longer
durations are necessary to produce sufficient observable change; and 56 hot diurnal cycles have
historically provided sufficient confidence to support an initial deployment of up to at least 6
months tactical storage. Chemical and physical processes may be simulated by constant
temperature stressing, but care must be exercised since such stressing may induce unrepresentative
failure modes or may not adequately exercise potential failure modes. Consideration must be given
to the design of the munition and any design limitations. For example, gas cracking, phase changes
or changes in the chemical reaction mechanism can occur during constant temperature ageing
which may not occur during diurnal cycling or in service. This test should not be conducted instead
of high temperature cycling, but may be used to supplement the chemical ageing effects of diurnal
cycling tests. If the munition under test could be susceptible to high temperature fluctuations, then
the A1 storage and transit (induced) cycle or that defined in the LCEP should be used.
A.1-4
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