Section R. 408.10121 - General requirementsRule 121.
(1) An abrasive wheel shall be provided with a guard, except as noted in this subrule, which shall cover the spindle end, nut, and flange projections, as well as the periphery, other than where work is to be performed (see figures). Exceptions are as follows:(a) Wheels used for internal grinding while advancing or retracting the work or while within the work.(b) Mounted wheels that are not more than 2 inches in diameter.(c) Plug and cones that are not more than 3 inches in diameter or 5 inches in length.(d) A type l reinforced wheel which is not more than 3 inches in diameter and 1/4 inch thick and with which safety glasses and face shield protection are provided and used as prescribed in Part 33. Personal Protective Equipment, being R 408.13301 et seq. of the Michigan Administrative Code.(e) Lapidary grinding. A metal diamond lapidary blade which is notched, segmented, or continuous rim and which is used within a coolant deflector does not require guards for speeds of not more than 3,500 sfpm.(f) Tuck point wheel, masonry, or concrete saws may have the spindle end, nut, and flange exposed as per figures 1 and 2 of R 408.10198.(2) The guard shall be constructed of material that is capable of retaining pieces of a broken wheel. See material tables. The guard shall be mounted so as to maintain alignment with the abrasive wheel to contain wheel breakage, and the strength of the fastenings shall exceed the strength of the guard. The guard shall be in position before starting the wheel.(3) Where flying particles or fragments are a hazard to employees other than the grinder operator, an enclosure or barrier shall be provided to isolate the operation from the remaining working area.(4) When openings in the wheel safety guard assemblies are required for dressing, a means shall be provided to protect the operator and other personnel from the hazards of flying particles, sparks, or wheel fragments.Mich. Admin. Code R. 408.10121
1979 AC; 1983 AACS; 1990 AACS