Use Environment per MIL HDBK-217F (Ground):
Ground, Benign: Nonmobile, temperature and humidity controlled environments readily accessible to maintenance; includes laboratory instruments and test equipment, medical electronic equipment, business and scientific computer complexes, and missiles and support equipment in ground silos.
Ground, Fixed: Moderately controlled environments such as installation in permanent racks with adequate cooling air and possible installation in unheated buildings; includes permanent installation of air traffic control radar and communications facilities.
Ground, Mobile: Equipment installed on wheeled or tracked vehicles and equipment manually transported; includes tactical missile ground support equipment, mobile communication equipment, tactical fire direction systems, handheld communications equipment, laser designations and range finders.
Back to the Mean Time Between Failure Definition, or the Military Specifications page.
Engineering Key Words: Failure Mode Analysis, Reliability Prediction, MIL-HDBK-217, Bellcore
/ Telcordia, IEC 62380
