Meeting & Exceeding Standards: Environmental Contaminants

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Previously, we reviewed water resistance and temperature testing in military standard MIL-STD-810G for environmental engineering. Further testing evaluates a device’s ability to withstand contaminants found in various environments.

Contamination by Fluids

For the purposes of this part of the standard, fluids refers to liquids beyond water, including but not limited to fuels, lubricating oils, solvents, cleaning fluids, anti-freeze, insecticides, coolants and fire extinguishants.

Large Items: For aircraft systems, wheeled and track vehicles, watercraft and others

For items exposed to occasional contamination
Fluids are applied to the entire surface of the item and allowed to drain for five to 10 minutes. The test item is left at standard ambient temperature for eight hours, then cleaned and inspected. If testing more than one fluid, multiple fluids are applied and allowed to drain without cleaning between applications.

For items exposed to intermittent contamination
Fluids are applied to the entire surface of the item and maintained for eight hours, then allowed to dry for 16 hours. The test chamber is kept at a temperature corresponding to the operational environment. After drying, the test item is stabilized at standard ambient temperature, cleaned and inspected before testing additional fluids.

For items exposed to extended contamination
The test item is immersed in fluid for a period according to the operational environment or at least 24 hours and then removed and allowed to drain for five to 10 minutes. The item is kept in the test chamber at a temperature corresponding to the operational environment for eight hours. Steps are repeated to test for prolonged exposure. Multiple fluids are applied without cleaning between applications.

Small Items: For weaponry, clothing, gas masks, ammunition, binoculars and other equipment

Fluid, including multiples, is applied to the item and maintained for one hour. The item is then inspected, and fluid is reapplied and maintained for an additional seven hours. The item is left to dry for a maximum of 24 hours.

Salt Fog in Marine Environments

Equipment is placed in the test chamber and temperature is set to 35°C and left for at least two hours. A salt solution is introduced into the chamber for 24 hours at a fall rate between 1 and 3 ml/80cm²/hr. The equipment dries at ambient temperature and at a humidity less than 50% for 24 hours. The entire process is repeated at least once.

Sand and Dust

Blowing Dust

Equipment is placed in the test chamber and wind velocity is set to approximately 9 m/s (1750 ft/min). Dust particles the size of < 150µm are introduced at a concentration of approximately 10 g/m3 (0.3 g/ft3) and maintained for at least six hours. The dust feed is ended and wind velocity reduced, and equipment is left to stabilize for one hour. Dust and wind velocity measures are reintroduced and maintained for at least six hours.

Blowing Sand

Equipment is placed in the test chamber and wind velocity is set between 18-29 m/s (40-65 mph). Sand particles between the size of 150-850µm are introduced at concentrations dependent on expected environment and hazardous nature of equipment tested. Equipment is rotated and blowing sand is maintained for 90 minutes per surface.

Fungal Growth in Humid Environments

Equipment is placed in the test chamber with any covers removed. Temperature is set to 30°C (86°F) and humidity is held between 90-99% for at least four hours. Equipment is sprayed with a mix of fungal spores. Covers of the equipment are replaced but not fastened and left to incubate for at least 28 days at maintained temperature and humidity.

Sealevel Environmental Testing

Sealevel performs rigorous in-house testing and designs solutions for equipment operating in hazardous conditions, including dust-tight products.