(C) Where employees are exposed to hazardous concentrations of air contaminants, the air contaminants shall be minimized by at least one of the following methods:
(1) Substitute a non-hazardous, or less hazardous material;
(2) Confine or isolate the contaminants;
(3) Remove at or near source;
(4) Dilution ventilation;
(5) Exhaust ventilation;
(6) Using wet methods to allay dusts. Note: Good housekeeping is of definite value in minimizing air contaminants created by dusts.
(D) Exhaust systems: machinery and equipment.
(1) Grinding, polishing and buffing.
(a) Abrasive wheels and belts.
(i) Abrasive wheels and belts shall be hooded and exhausted when there is a hazardous concentration of air contaminants.
(ii) This does not apply to abrasive wheels or belts:
(a) Upon which water, oil, or other liquid substance is used at the point of the grinding contact; or
(b) To small abrasive wheels used occasionally for tool grinding.
(b) Separate exhaust systems.
Abrasive wheel and buffing wheel exhaust systems shall be separate when the dust from the buffing wheel is of flammable material.
(2) Generation of toxic materials.
When toxic materials are generated in hazardous concentrations during their application, drying, or handling, they shall be minimized or eliminated by at least one of the methods described in paragraph (C) of this rule.
(3) Internal combustion engines.
Hazardous concentrations of air contaminants produced by internal combustion engines shall be exhausted.
(E) Exhaust systems - structural requirements.
(1) Exhaust or ventilating fan.
Each exhaust or ventilating fan located less than seven feet above the floor or normal working level shall be guarded.
Exhaust ductwork shall be sized in accordance with good design practice which shall include consideration of fan capacity, length of duct, number of turns and elbows, variation in size, volume, and character of materials being exhausted.
The outlet from every separator or (collector) shall discharge the air contaminants collected by the exhaust system, in such manner that the discharged materials shall not re-enter the working area in hazardous concentrations.
(4) Location of air supply openings or inlets.
Air supply openings or inlets through which air enters the building or room in which the local exhaust system is in operation shall be isolated from any known source of contamination from outside of the building.
Five Year Review (FYR) Dates: 03/14/2016 and 06/01/2021
Promulgated Under: 119.03
Statutory Authority: 4121.12, 4121.121, 4121.13
Rule Amplifies: 4121.47
Prior Effective Dates: 4/1/64; 8/1/77; 1/1/86, 4/10/11