MSHA - Code of Federal Regulations - 30 CFR 57.4000
Skip to content
MSHA - Title 30 CFR
30 CFR § 57.4000

The following definitions apply in this subpart.

Combustible liquids. Liquids having a flash point at or above 100°F (37.8 °C). They are divided into the following classes:

Class II liquids--those having flash points at or above 100 °F (37.8 °C) and below 140 °F (60 °C).

Class IIIA liquids--those having flash points at or above 140 °F (60 °C) and below 200 °F (93.4 °C).

Class IIIB--liquids those having flash points at or above 200 °F (93.4 °C).

Escapeway. A designated passageway by which persons can leave an underground mine.

Flash point. The minimum temperature at which sufficient vapor is released by a liquid to form a flammable vapor-air mixture near the surface of the liquid.

Main fan. A fan that controls the entire airflow of an underground mine or the airflow of one of the major air circuits of the mine.

Mine opening. Any opening or entrance from the surface into an underground mine.

Safety can. A container of not over five gallons capacity that is designed to safely relieve internal pressure when exposed to heat and has a spring-closing lid and spout cover.