California Code of Regulations (Last Updated: August 6, 2014) |
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 107. Dusts, Fumes, Mists, Vapors and Gases |
§ 5152. Ventilation and Personal Protective Equipment Requirements for Grinding, Polishing, and Buffing Operations.
Latest version.
- (a) General. Every establishment performing dry grinding, dry polishing, or buffing shall provide suitable hoods or enclosures that are connected to exhaust systems which are run continuously during operations.Exception: When the concentration at the operator's breathing zone of any airborne contaminant generated by such an operation is below the applicable limit prescribed in Section 5155 or any other section of Title 8.(b) Hood and Branch Duct Performance Requirements.(1) Hoods connected to exhaust systems shall be used, and such hoods shall be designed, located, and placed so that the dust or dirt particles shall fall or be projected into the hoods in the direction of the air flow. No wheels, discs, straps, or belts shall be operated in such manner and in such direction as to cause the dust and dirt particles to be thrown into the operator's breathing zone.(2) Wheels and belts shall have not less than the minimum exhaust volumes shown in the following tables:TABLE V-1.GRINDING AND ABRASIVE CUTTING-OFF WHEELS.Wheel DiameterWheel WidthMinimum Exhaust Volume(Inches)(Inches)(Cubic Feet/Min.)To 91 1/2220Over 9 to 162390Over 16 to 193500Over 19 to 244610Over 24 to 305880Over 30 to 3661200HISTORY1. New section filed 7-18-75; effective thirtieth day thereafter (Register 75, No. 29).2. Amendment filed 7-16-76; effective thirtieth day thereafter (Register 76, No. 29).3. Amendment of subsection (a) filed 4-27-79; effective thirtieth day thereafter (Register 79, No. 17).4. Change without regulatory effect providing more legible illustrations for Figures V-1, V-2, V-3, V-4, V-5, V-6, V-7 and V-8 filed 3-2-2009 pursuant to section 100, title 1, California Code of Regulations (Register 2009, No. 10).
Note
Note: For any wheel wider than that shown, increase the table exhaust volume by the ratio of the actual width to the table width. Example: For wheel width = 4 1/2 inches. Minimum Exhaust Volume = 4.5/4 x 610 = 686 (rounded to 690).TABLE V-2BUFFING, POLISHING, AND SCRATCH-BRUSH WHEELSWheel DiameterWheel WidthMinimum Exhaust(Inches)(Inches)(Cubic Feet/Min.)To 92300Over 9 to 163500Over 16 to 194610Over 19 to 245740Over 24 to 3061040Over 30 to 3661200TABLE V-3HORIZONTAL SPINDLE DISC GRINDERWheel DiameterMinimum Exhaust Volume(Inches)(Cubic Feet/Min.)Single SpindleDouble SpindleUp to 12220610Over 12 to 19390610Over 19 to 25610880Over 25 to 306101200Over 30 to 538801770Over 53 to 728806280TABLE V-4VERTICAL SPINDLE DISC GRINDERDisc DiameterOne-half or More of Disc CoveredDisc not Covered(Inches)Exhaust VolumeExhaust VolumeNumber [FN1](Cubic Feet/Min.)Number [FN1](Cubic Feet/Min.)Up to 2015002780Over 20 to 30278021480Over 30 to 532177043530Over 53 to 722314056010[FN1] Number of exhaust outlets around periphery of hood, or equal distribution provided by other means.TABLE V-5GRINDING AND POLISHING BELTSBelts WidthExhaust Volume(Inches)(Cubic Feet/Min.)Up to 3220Over 3 to 5300Over 5 to 7390Over 7 to 9500Over 9 to 11610Over 11 to 13740(3) Cradles requiring partial enclosures to house the complete operation shall be ventilated sufficiently such that a minimum air velocity of 150 feet per minute shall be maintained over the entire opening of the enclosure.(c) Hood Design.(1) Vertical-spindle disc grinders shall be encircled with a hood so constructed 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 V-1.(2) Exhaust hoods for floor stands, pedestals, and bench grinders shall be designed as effective as Figure V-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.(3) Swing-frame grinders shall be exhausted in the same manner as provided for cradles, and shall be provided with exhaust booths as indicated in Figure V-3.(4) Hoods for polishing and buffing and scratch-brush wheels shall be constructed to conform as closely to Figure V-4 as the nature of the work will permit.(5) Cradle grinding and polishing operations shall be performed within a partial enclosure similar to Figure V-5. The operator shall be positioned outside the working face of the opening of the enclosure. Cradle enclosures shall be ventilated sufficiently such that a minimum air velocity of 150 feet per minute shall be maintained over the entire opening of the enclosure.(6) Hoods for horizontal single-spindle disc grinders shall be constructed to conform as closely as possible to the hood shown in Figure V-6.(7) Horizontal double-spindle disc grinders shall have a hood encircling the wheels and grinding chamber similar to that illustrated in Figure V-7. The openings for passing the work into the grinding chamber should be kept as small as possible, but must never be less than twice the area of the branch outlets.(8) 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 wide openings should be provided on either side. Figure V-8 shows a typical hood for a belt operation.(d) Portable Operations.Portable grinding, polishing, and buffing operations, whenever the nature of the work permits, shall be conducted within a partial enclosure over which an average face air velocity of not less than 200 feet per minute shall be maintained, or a low volume, high velocity local exhaust hood attachment shall be used. (Title 24, T8-5152)FIGURE V-1VERTICAL SPINDLE DISC GRINDER EXHAUST HOOD AND BRANCH PIPE CONNECTIONSFIGURE V-2STANDARD GRINDER HOODFIGURE V-3A METHOD OF APPLYING AN EXHAUSTENCLOSURE TO SWING-FRAME GRINDERSNote: Baffle to reduce front opening as much as possible.FIGURE V-4STANDARD BUFFING AND POLISHING HOODFIGURE V-5CRADLE POLISHING OR GRINDING ENCLOSUREEntry Loss = 0.45 velocity pressure for tapered takeoffFIGURE V-6HORIZONTAL SINGLE-SPINDLE DISC GRINDEREXHAUST HOOD AND BRANCH PIPE CONNECTIONSNote: If grinding wheels are used for disc grinding purposes, hoods must conform to structural strength and materials as described in 9.1.Entry Loss = 0.45 velocity pressure for tapered takeoff.FIGURE V-7HORIZONTAL DOUBLE-SPINDLE DISC GRINDEREXHAUST HOOD AND BRANCH PIPE CONNECTIONSFIGURE V-8A TYPICAL HOOD FOR A BELT OPERATIONBelt Width W, inchesExhaust Volume, ft3/min.up to 32203 to 53005 to 73907 to 95009 to 1161011 to 13740Minimum duct velocity = 4,500 ft/min branch, 3,500 ft/min main.Entry loss =0.45 velocity pressure for tapered takeoff.0.65 velocity pressure for straight takeoff.Note: Authority and reference cited: Section 142.3, Labor Code.