California Code of Regulations › Title 8 - Industrial Relations › Division 1 - Department of Industrial Relations › Chapter 4 - Division of Industrial Safety › Subchapter 7 - General Industry Safety Orders › Group 16 - Control of Hazardous Substances › Article 109 - Hazardous Substances and Processes › Section 5174 - Combustible Dusts-General

Current through Register 2024 Notice Reg. No. 28, July 12, 2024
(a) Any action which liberates combustible
						dust that exceeds or may reasonably be expected to exceed a concentration of 25
						percent of its lower explosive limit in air shall not be permitted unless all
						sources of ignition are eliminated or are identified and specifically
						controlled.
NOTE: Most combustible materials and some materials not
						  usually considered combustible when reduced to dust or powder form, present an
						  explosion hazard when mixed with air.
(b) No source of ignition shall be permitted
						in locations where a hazard of dust explosion exists until all dust-producing
						operations have been stopped, airborne dust allowed to settle, and accumulated
						dust removed to an extent which will remove the hazard of the dust
						explosion.
(c) All machines,
						conveyors, housings, and conductive surfaces in locations where combustible
						dusts are generated or are present shall be electrically bonded to ground to
						prevent the accumulation of electrostatic charges which are sufficient to
						potentially cause dust ignition.
(d) Hoses and nozzles used in the collection
						or blowing of dusts shall have electrical continuity maintained along the
						entire length from coupling to nozzle and shall be bonded to ground.
(e) Static electricity shall be removed from
						belts by grounded metal combs or other effective static elimination devices.
NOTE: Ground/grounded see definition of Grounded,
						  Effectively in Section
						  3207.
(See Electrical Safety Orders for regulations governing
						  electrical installations in locations where combustible dusts are generated, or
						  are present.)
(f) All
						enclosed areas wherein combustible dusts are generated or are present, except
						in closed or covered containers shall be cleaned as often as necessary to
						prevent accumulation of dust on floors, ledges, beams, equipment, machines or
						elsewhere which may present a fire or explosion hazard. Safe means of access
						for cleaning of all surfaces shall be provided.
NOTE:
(1) The
						cleaning of surfaces by a permanently installed grounded vacuum cleaning system
						is the preferable method. Soft push brooms or brushes may be used without
						serious hazard except where brushed dust may form explosive clouds in air.
						(Warning: Brush bristles of synthetic fiber have a tendency to accumulate
						strong electrostatic charges.) Blowing dust with compressed air may create
						dangerous dust clouds and such cleaning should be done only when other methods
						cannot be used and after all possible sources of ignition have been eliminated,
						including bonding hoses and nozzles to ground.
NOTE:
(2) See Section
						5144 for respiratory protective
						equipment requirements.