Section 9 – Explosive Atmosphere:
This test is designed to demonstrate equipment’s capability to operate as intended in a environment where flammable conditions exist, without causing an explosion, or to confirm equipment is able to prevent an explosion from spreading outside of the enclosure of the equipment. This test is considered a sequential reference test when using a single test article for a multi test program.
Specific Test Types
Non-ignition Test (equipment does not ignite surrounding flammable vapors)
Containment Test (internal explosion does not propagate outside equipment )
Components or Surface Temperature Test (verifies hotspots do not ignite vapor)
Equipment Environments
Environment I (continuous/intermittent flammable vapors, e.g. fuel tanks)
Atmosphere where uncovered flammable fluids or vapors exist, or can exist, either continuously or intermittently such as in fuel tanks or within fuel systems.
Environment II (flammable vapers present only due to faults/leaks)
Atmosphere where flammable fluids or vapor mixtures can be expected to occur only as a result of a fault-causing spillage or leaking.
Environment III (designated fire zones)
Atmosphere within a known, designated fire zone.
Equipment Categories
Category A
Equipment designed to operate based on these requirements:
- Normal intended operation where the temperature of any surface will not rise to a level capable of causing ignition, nor will any operating part cause ignition.
- Ignition of an explosive mixture must be contained within the equipment without igniting explosive atmosphere surrounding equipment.
- During normal operation, or as a result of any fault, the temperature of any external surface will not rise to a level capable of causing ignition.
Category E
Equipment that is not hermetically sealed and not contained in those cases, designed to prevent flame and explosion propagation. This type of equipment is not intended for installation or use in Environment I. Equipment shall be designed so that during operation, the temperature of any internal or external surface will not rise to a level capable of causing ignition, and will not allow for any operating internal part to cause ignition so that it meets the non ignition test.
Category H (non-spark producing, hot spot monitoring)
Equipment, including hermetically sealed equipment, does not contain hot spot surfaces (external or internal) and will not produce sparks producing normal operating conditions. Equipment shall be designed so that under normal operation conditions, the temperature of any internal or external surface will not rise to a level that can cause ignition so that it meets the components or surface temperature test. Any hermitically sealed equipment meeting temperature requirements on external
surface shall be identified as Category H equipment.
DLS provides support for the RTCA DO 160G sections on EMI/EMC Electromagnetic Interference and Compatibility, EMI/EMC RTCA-DO-160 Testing.
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