Explosive atmospheres testing for defence

The commonly used explosive atmosphere test for military applications is taken from MIL-STD 810F. The test of method 511.4 is performed to demonstrate the ability of equipment to operate in fuel-air explosive atmospheres without causing ignition. This method applies to all equipment designed for use in the vicinity of fuel-air explosive atmospheres associated with aircraft, automotive, and marine fuels at or above sea level (up to 12,200 metres).

Testing in the UK
Elevated ambient temperatures up to 70ºC
Standard chamber for equipment <0.5m³
Special chambers for larger equipment >0.5m³
TRaC testing currently available at sea level only (altitude testing available soon)

Generally, explosive atmosphere test for military applications is conducted on sub-assemblies and smaller items of equipment (<1m³). TRaC can test most sizes of equipment and we specialise in testing larger items. Please contact us for more information on special tests.

The explosive atmosphere test is a conservative test. If the test item does not ignite the test fuel-air mixture, there is a low probability that it will ignite prevailing fuel vapour mixtures in service. Conversely, the ignition of the test fuel-air mixture by the test item does not mean that it will always ignite fuel vapours that occur in actual use.

The test of method 511.4 is usually applied after completion of environmental stress tests (detailed elsewhere in MIL-STD 810F). This ensures that seals and enclosures are representative of service use. The test is normally conducted at highest operating service ambient conditions.

The effect of altitude is taken into account during this test because the energy required to ignite a fuel-air mixture increases as pressure decreases. Tests are normally performed with at least two explosive atmosphere steps, one at the highest anticipated operating altitude of the equipment (not to exceed 12,200 metres where the possibility of an explosion begins to dissipate) and one which is representative of most ground ambient pressures.

« back to top