Testing & Certification

Purpose of Tests

The first procedure

determines if a product will operate in an explosive atmosphere without igniting the vapors. This is important in aircraft or confined spaces where there isn’t much ventilation, creating the potential for a mixture of fuel and fuel air. The test makes sure there isn’t an ignition source in the environment. To do this test, the article goes into a chamber with a hexane and air fuel mixture, and the temperature is elevated. Then the equipment is fully operated by activating some switches and turning things on and off to see if there are any sparks or ignition sources that ignite the fuel air mixture. The latter is done remotely to avoid getting inside the chamber. This applies primarily to military applications. The oil and gas industry uses a completely different spec, ATEX, to test for explosive atmosphere.

The second procedure

tests to determine if the article will come apart if there’s fuel inside the unit and an ignition source.

Effects of explosive atmosphere environments.

Low levels of electrical energy discharge or electrical arcing by devices as simple as pocket transistor radios can ignite mixtures of fuel vapor and air. A "hot spot" on the surface of the case of a hermetically sealed, apparently inert materiel case can ignite fuel-air mixtures. Fuel vapors in confined spaces can be ignited by a low energy discharge such as a spark from a short circuited flashlight cell, switch contacts, electrostatic discharge, etc