The following definitions apply in this part.

Applicant An individual, partnership, company, corporation, association, or other organization, that designs, manufactures, assembles, or controls the assembly and that seeks a certificate of approval or preliminary testing of mobile diesel-powered transportation equipment as permissible.

Certificate of approval. A formal document issued by MSHA stating that the complete assembly has met the requirements of this part for mobile diesel-powered transportation equipment and authorizing the use and attachment of an official approval plate so indicating.

Component. A piece, part, or fixture of mobile diesel-powered transportation equipment that is essential to its operation as a permissible assembly.

Diesel engine. A compression-ignition, internal-combustion engine that utilizes diesel fuel.

Explosion proof. A component or subassembly that is so constructed and protected by an enclosure and/or flame arrester (s) that if a flammable mixture of gas is ignited within the enclosure it will withstand the resultant pressure without damage to the enclosure and/or flame arrester(s). Also the enclosure and/or flame arrester(s) shall prevent the discharge of flame or ignition of any flammable mixture that surrounds the enclosure.

Flame arrester. A device so constructed that flame or sparks from the diesel engine cannot propagate an explosion of a flammable mixture through it.

Flammable mixture. A mixture of gas, such as methane, natural gas, or similar hydrocarbon gas with normal air, that will propagate flame or explode violently when initiated by an incendive source.

Fuel-air ratio. The composition of the mixture of fuel and air in the combustion chamber of the diesel engine expressed as weight-pound of fuel per pound of air.

MSHA. The United States Department of Labor, Mine Safety and Health Administration.

Mobile diesel-powered transportation equipment. Equipment that is:

(1) Used for transporting the product being mined or excavated, or for transporting materials and supplies used in mining or excavating operations;

(2) Mounted on wheels or crawler treads (tracks); and

(3) Powered by a diesel engine as the prime mover.

Normal operation. When each component and the entire assembly of the mobile diesel-powered transportation equipment performs the functions for which they were designed.

Permissible. As applied to mobile diesel-powered transportation equipment, this means that the complete assembly conforms to the requirements of this part, and that a certificate of approval to that effect has been issued.

Subassembly. A group or combination of components.