R 408.42402 Tar kettle construction.

Rule 2402. (1) A tar kettle vat for molten material shall be of welded construction and all other materials of the tar kettle, except tires, used in its construction shall be noncombustible. A tanker for molten material shall be braced and baffled to contain the load. (2) A cover for a tar kettle vessel shall be hinged, close fitting, and capable of smothering a fire inside the vessel, when in a closed position. (3) A discharge valve from a tar kettle vessel shall be a quick closing type with standard pipe thread. (4) Pipe, tubing, hose, and conductors used for hot material from a tar kettle or tanker shall be supported when above ground or floor level. Hose, tubing, pipe, and conductors running horizontally shall be supported at intervals that will prevent sagging. Connections shall be made with unions or couplings and shall be maintained free of leaks. (5) Where a pump unit is mounted on a tar kettle and the fuel container is an integral part of the pump, the pump unit shall be shielded from the tar kettle by a barrier of rigid noncombustible material.