Downloaded from https://www.everyspec.com A AMCP MIN10 CHAPTER 6 ENVIRONMENTAL TESTING 6"1 INTRODUCTION 0A In environmental testing, an equipment is All environmental tests have the common tested under varlo s environmental conditions objectives of determining the effect of the of temperature, vibration, radiation, humidity, environmental conditions on an item or etc., in order4o determine or verify its caps- verifying that the item is capable of with- bility to operate satlsfnctorily when sub- standing them. These tests are now employed jected to stress.
Strnigth, lire, and perfor- in essentially all phases of hardware pro- mance tests, as we', as other basic test types, grams from the parts and materials level to may all involve environmental testing. In large systems. In programs relying primarily some hardware development programs, a on a "build and test" approach, they pro. particular phase of the testing program vide assurance in operational hardware, formally is designated as environmental testing, An alternative to environmental testing is testing under field conditions.
This alterna- The affect of environmental conditions, tive can provide the desired assurance, but whether man-made or not, on equipment is usally costs more (especially in the case of an important consideration in reliable design, complex, expensive items) and often delays Environmental testing is performed because the desired information. In field testing, of the uncertainty of the effects of the en- test conditions generally are not as well con- vironment, The uncertainty of the environ- trolled as in environnmental testing, so that SilOnt can only be accounted for by conser- cause and effect relationships may be ob- vative design practices and/or by adequate scured. field testing.
Environmental tasting ranges in sophis- In some environmental testing, there is a ticatiun from very crude methods, such as deliberate attempt to simulate as closely as using an improvised temperature chamber, to possible the environmental profile expected testig in very elaborate facilities permitting during equipment operation, This Is occa- many conbinations of conditions to be sim- sionally done, for example, in reliability dem- telated. Tests may be purposely destructive onstratlon with samples of prototype hard- (as in strength and life testing), or nonde- ware.
Usually, certain critical features of the structive (such as proof tests and burn-in), total operational environment are simulated at specific severity levels in order to uncover The appropriate test conditions must be design and material weaknesses and workman- carefully selected. Basic factors to consider ship errors, In still other cases (such as de- are: velopment tests), the operational environment may not be known and test conditions con- I. The possible environmental conditions sequently cover a wide range. during intended use of the equipment 4. I. .J VAI•, '•'.•;,,