Michigan Administrative Code › Department - Labor and Economic Opportunity › MIOSHA › General Industry and Construction Safety and Occupational Health Standards › Occupational Health Standards › Part 525 - GRINDING, POLISHING, AND BUFFING OPERATIONS › Section R. 325.52506 - Hood and enclosure design

Current through Vol. 24-12, July 15, 2024
Rule 6.
(1) It
					 is the dual function of grinding and abrasive cutting-off wheel hoods to
					 protect the operator from the hazards of bursting wheels and to provide a means
					 for the removal of dust and dirt generated. All hoods shall be not less in
					 structural strength than specified in the American National Standard Safety
					 Code for the Use, Care, and Protection of Abrasive Wheels, B7.1-1970. ANSI
					 B7.1-1970 is adopted by reference in this rule. Printed copies of ANSI
					 B7.1-1970 are available from Global Engineering Documents, 15 Inverness Way
					 East, Englewood, Colorado 80112, telephone number 1-800-854-7179, website:
					 www.global.ihs.com [File Link Not Available], at a cost as of the time of
					 adoption of these rules of $45.00 or is available for inspection at the
					 Michigan Department of Consumer and Industry Services, Standards Division, 7150
					 Harris Drive, P.O. Box 30643, Lansing, Michigan 48909.
(2) Due to the variety of work and types of
					 grinding machines employed, hoods shall adapt to the particular machine in
					 question, and such hoods shall be located as close as possible to the
					 operation.
(3) Exhaust hoods for
					 floor stands, pedestals, and bench grinders shall be designed in accordance
					 with Figure G-2. The adjustable tongue shown in the figure shall be kept in
					 working order and shall be adjusted within one-fourth inch of the wheel
					 periphery at all times.
(4)
					 Swing-frame grinders shall be provided with exhaust booths as indicated in
					 Figure G-3.
(5) Portable grinding
					 operations, whenever the nature of the work permits, shall be conducted within
					 a partial enclosure. The opening in the enclosure shall not be larger than is
					 actually required in the operation and an average face air velocity of not less
					 than 200 feet per minute shall be maintained.
(6) Hoods for polishing and buffing and
					 scratch-brush wheels shall be constructed to conform as closely to Figure G-4
					 as the nature of the work will permit.
(7) Cradle grinding and polishing operations
					 shall be performed with a partial enclosure similar to Figure G-5. The operator
					 shall be positioned outside the working face of the opening of the enclosure.
					 The face opening of the enclosure should not be greater in area than that
					 required for the performance of the operation, and the average air velocity
					 into the working face of the enclosure shall not be less than 150 feet per
					 minute.
(8) Hoods for horizontal
					 single-spindle disc grinders shall be constructed to conform as closely as
					 possible to the hood shown in Figure G-6. There shall be a space between the
					 back of the wheel and the hood, and a space around the periphery of the wheel
					 of at least 1 inch to permit the suction to act around the wheel periphery. The
					 opening on the side of the disc shall not be larger than is required for the
					 grinding operation, but shall not be less than twice the area of the branch
					 outlet.
(9) Horizontal
					 double-spindle disc grinders shall have a hood encircling the wheels and
					 grinding chamber similar to that illustrated in Figure G-7. The openings for
					 passing the work into the grinding chamber should be kept as small as possible,
					 but shall not be less than twice the area of the branch outlets.
(10) Vertical-spindle disc grinders shall be
					 encircled with a hood constructed so that the heavy dust is drawn off a surface
					 of the disc and the lighter dust exhausted through a continuous slot at the top
					 of the hood as shown in Figure G-1.
(11) Grinding and polishing belt hoods shall
					 be constructed as close to the operation as possible. The hood should extend
					 almost to the belt, and 1-inch openings should be provided on either side.
					 Figure G-8 shows a typical hood for a belt operation. R. 325.52506 Tables and
					 Charts
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Figure G-1
Vertical Splndla Disc Grinder Exhaust Hood and
						Branch Pipe Connections
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Figure G-2
Standard Grinder Hood
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Figure G-3
A Method of Applying an Exhaust Encloser Swing-frame
						Grinders
Note: Baffle to reduce front opening as much as
						possible.
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Figure G-4
Standard Buffing and polishing Hood
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Figure G-5
Cradle Polishing or Grinding
						Enclosure
Entry loss " 0.44 velocity pressure for tapered
						takeoff.
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Figure G-6
Horizontal Single-Spindle Disc Grinder Exhaust
						flood and Branch Pipe Connections
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Figure G-7
Rorlsontal Double-Splndle Disc Grinder Exhaust Hood
						and Branch Pipe Connections
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Figure G-8
A Typical Hood for a belt Oparation
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