The BestTest Newsletter

Whenever someone thinks of environmental tests, the age-old MIL-STD-810, entitled "Department of Defense Test Method Standard for Environmental Engineering Considerations and Laboratory Tests" comes to mind. It is issued by the United States Army's Developmental Test Command, to specify various environmental tests to prove that equipment qualified to the standard will survive in the field. The current revision, as of 2006, is revision F, issued January 1, 2000, superseding revision E from 1989. The standard is thus commonly referred to as MIL-STD-810F.

Revisions up to Rev C used fairly generic tests for various classes of gear. Once Rev D came around (Circa 1985) the testing, in particular shock and vibration were more tailored for the actual expected operating environment.

It is important to know what exactly you are testing for in each of the cases. A complete list of Laboratory Test Methods is shown in the Table below:

Test	Description
500	Low Pressure (Altitude)
501	High Temperature (Both storage and operating)
502	Low Temperature (Both storage and operating)
503	Temperature Shock (How well does the device handle going from high to low temps, and back)
504	Contamination by Fluids
505	Solar Radiation (Sunshine)
506	Rain (How does the device do in wind blown rain)
507	Humidity (Can it handle high Humidity?)
508	Fungus (Device is exposed to warm moist air in the presence of Fungus to see if it grows on the device)
509	Salt Fog (Does it rust/fail when exposed to salt fog?)
510	Sand and Dust (How well does the unit work when exposed to - you guessed it - sand and dust)
511	Explosive Atmosphere (Does it create enough sparks/etc to cause an explosive atmosphere to blow up?)
512	Immersion
513	Acceleration (Constant acceleration)
514	Vibration
515	Acoustic Noise
516	Shock (Either Shock Response Spectrums, or Triangle/sine/square wave shocks) - also Transport Shock
517	Pyroshock
518	Acidic Atmosphere
519	Gunfire
520	Temperature, Humidity, Vibration, and Altitude (Traditionally sine wave (pre D) - later random vibration - combined with Temp testing)
521	Icing/Freezing Rain
522	Ballistic Shock
523	Vibro-Acoustic/Temperature

Environmental test reports are produced at various points in the acquisition process. Specifications for conducting development and operational tests and formats for resulting reports are provided by development and operational test agencies. This task pertains mainly to the results of materiel tests performed in environmental testing laboratories. The ETR defines the test purpose, lists test issues/criteria, lists or describes test equipment/facilities/instrumentation, explains the test design/set-up, contains detailed test data/logs, provides failure analyses, and interprets test results. The laboratory ETR is appropriate for design evaluation tests, operational worthiness tests, and qualification tests. Data from these laboratory tests serve as early warnings of unanticipated deviations from performance requirements. They support failure analyses and corrective actions related to the ability of materiel to withstand specific environmental conditions. These laboratory test data do not serve as substitutes for development or operational tests conducted in natural field/fleet environments.

Design engineers conduct engineering analyses that predict responses of materiel to the stresses of the environmental life cycle. These analyses are used to prepare materiel designs that incorporate necessary resistances to environmental stresses, to modify test criteria to account for factors that cannot be fully accounted for in laboratory testing, and to interpret test results during failure analyses and redesign.

Test engineers develop test implementation plans/instructions that are carried out by other engineers or facility operators. Facility operators conduct tests according to direction established in system test planning and assessment documents and specific instructions prepared by test engineers/scientists who base their procedures on the environmental tailoring process. As a result of the tailoring process, laboratory testers will conduct only those tests that are appropriate, using exposure levels that will be neither too high nor too low because they will have been established according to the environments and levels that the materiel would be expected to see throughout its service life. In the same manner, field/fleet testers will conduct tests in those natural environments in which the materiel is expected to operate.

MIL-STD-810 provides tolerances for temperature, pressure, humidity, vibration amplitude and frequency, acceleration, time, air velocity and water purity.