30 CFR § 7.502
The following definitions apply in this subpart:
. A measure of relative discomfort due to the
combined effects of air movement, heat, and humidity on the human body.
. Oxygen that is at least 99 percent pure with no
. A fire that rapidly spreads through a diffuse fuel,
such as airborne coal dust or methane, without producing damaging
. Material, such as concrete or steel, that
will not ignite, burn, support combustion, or release flammable vapors
when subjected to fire or heat.
. The highest pressure over the background atmospheric
pressure that could result from an explosion, which includes the impact
of the pressure wave on an object.
. A protected, secure space with an isolated
atmosphere and integrated components that create a life-sustaining
environment for persons trapped in an underground coal mine.