This printed copy is only valid for 17/04/2018 RICHARDS BAY MINERALS
EFFECTIVE DATE: 31 July 2012 Applicable to All divisions Number E 54 GP 001 Revision No. 4 Page 1 of 5 SAFE USE OF ANGLE GRINDERS
Cutting, Grinding, Sanding and Polishing. Compiled by: Reliability Engineer: RMM Final Products
Review By: Manager: Reliability and Asset Management
1. OBJECTIVE
Angle grinders are considered potentially dangerous tools and the activity of grinding or cutting with angle grinders have resulted in numerous harm incidents. These tools however can be safely applied in the work place provided that good safety practises are followed.
2. STATEMENT OF OBJECTIVE
The objective of this procedure is to provide guidelines for the safe use of all Angle grinders at RBM.
3. DEFINITIONS
Dead man switch: A switch on the handle that requires pressure to be applied for the operation of the unit and will automatically return to the off position when pressure is released.
Spindle lock: A mechanical device incorporated to lock the spindle to assist with the disc changing
Soft start: An electronically controlled system to control the ramp up speed at start up (electric grinders).
Anti vibration handle: Handle to reduce the vibration stress transferred to the users’ hand. Brake system: A system to reduce the run on time after the machine has been switched off.
4. ROLES AND RESPONSIBILITIES
It is the responsibility of each person that uses, operates, maintains, cleans, inspects and observes the function of an angle grinder to apply all aspects of this GP.
5. THE MAIN CAUSES OF INJURIES ASSOCIATED WITH ANGLE GRINDERS Metal particles lodging in the operators eye
Kick back, where the grinder is thrust back violently towards the operator due to the jamming of the disc in the work piece
Disc shattering and sending pieces flying in all directions.
Inhalation of dust and fumes generated during grinding and cutting Noise during grinding and cutting
This printed copy is only valid for 17/04/2018 Electric shock from ill maintained supply cord
Cuts and lacerations from placing the grinder down before the disc stops spinning Improper body positioning
6. PERSONAL PROTECTIVE EQUIPMENT Hard hat
Gloves
Safety glasses
Overalls with long sleeves and long pants, avoid any form of loose clothing Safety boots
Hearing protection
Breathing apparatus where dust or fumes may be generated
Where, grinding machines are used, a face shield is to be worn as extra protection to the safety glasses.
Certain tasks may require the use of a leather apron as determined by a risk assessment.
7. CUTTING TASKS
A 230mm angle grinder may not be used for free cutting purposes. The Plant Engineer (2.13.3.1 appointee) may approve exceptions only if alternative methods evaluated proved more hazardous or no alternative exists. The risk assessment for the task should then specifically include mitigating measures to ensure the safest possible way of performing the task.
Alternatives for consideration.
The use of a 115 or 125mm ” Baby” grinder
The use of a plasma cutter, guillotine, power hacksaw, shear or nibbler, CNC saw or cut off machine with slow moving metal blade.
A grinder positioned in a stand designed for that make of grinder and purpose. 8. GRINDING TASKS
The use of 230mm angle grinders for grinding purposes is acceptable, however should this form of grinding be required the 115mm or 125mm grinders would be preferable.
9. SANDING, POLISHING AND WIRE BRUSHING
When sanding/polishing and wire brushing tasks are to be done, it must be done using a machine designed for the purpose such as Bosch GPO12/E or equivalent.
Note: An angle grinder shall not be used for this purpose
10. MACHINE REQUIREMENTS FOR ALL USES
All Angle grinders must have a dead man switch incorporated with a pressure switch in the handle.
This printed copy is only valid for 17/04/2018
A 230mm electrical angle grinder units must incorporate a soft start to reduce the starting strain and a braking system to reduce run on after the unit has been switched off.
A spindle lock to assist with changing the disc or grinding wheel
Anti vibration handles are recommended to further reduce the stress if used for extended periods.
Angle grinders to be equipped and operated with disc guarding at all times
11. CUTTING AND GRINDING DISCS
Before use and mounting of discs it is essential to check the safety codes and specifications printed on the upper side of the disc. Such specifications include the following:
Revolutions per minute (RPM). The allowable speed of the disc must be equal or greater than the maximum achievable speed of the grinder.
Disc physical dimensions (Metric/ Imperial) to meet grinder specification.
The disc must be suitable for the material type to be cut/ ground as indicated on the disk
Cutting discs must never be used for grinding or vice versa 12. DISC MOUNTING
It is critical that the correct disc mounting procedure is followed. Check machine spindle, backup washer and thread.
Check the condition of spindle nut - ensure spanner drive holes are not elongated.
Ensure spindle nut spanner is the recommended tool by machine manufacturers. Do not use a hammer, pipe or chisel to tighten nut or apply additional mechanical
advantage to nut torque. A firm "nip" is sufficient to retain disc.
Ensure spindle diameter is suited to disc bore. Excessive clearance will cause machine to vibrate due to eccentricity.
Check to see that nut and backup washer do not "bottom out". This will result in the disc not being correctly clamped on the spindle.
Ensure the spindle speed is marked on the grinder and this it is less than the allowable disc speed.
13. COMPETENCY REQUIREMENTS
Employees required to use angle grinders must be assessed by the relevant supervisor to determine competency.
The technical training centre can provide training and perform competency assessment if required.
14. PROCUREMENT
Grinders
No specific SANS standard currently regulates the manufacture of hand held Angle grinders, however “Bosch” angle grinders meet all the requirements of this GP. Other manufactures will be considered should they conform to these standards in future. These manufacturers must be approved by the RMM manager before used on site.
This printed copy is only valid for 17/04/2018 Discs
Only the "Pferd" brand discs are to be used.
Website www.kiloton.co.za for information on Pferd discs. 15. STORAGE OF GRINDERS AND DISCS
Grinders will be stored without the discs fitted.
Discs will be stored on a peg as shown in the drawing below.
Discs will always be dry and free of oil. Any discs that get wet or absorb oil are to be disposed of.
16. INSPECTIONS AND RECORD KEEPING
The equipment will be identified, registered and inspected in accordance with the requirements of COP 54.
17. REFERENCES
RA\SWA\JTA – General grinding. This is a generic document to assist the team in identifying the hazards before any cutting or grinding takes place.
COP 54 – Portable, Moveable and fixed electrical equipment
Bosch Operating instruction Manual GP0 12/E – available on the Bosch Internet site – www.bosch-professional.com
This general procedure supersedes the following procedures o SEP Use of Grinding and Cutting ZZ SEP 022 o SOP Use of grinding and cutting discs ESBSSOP09
10
0To suit spindle
This printed copy is only valid for 17/04/2018 18. REVIEW HISTORY
REV NO DESCRIPTION PAGES (S) DATE
0 First Draft All January 2008
1 Added Point 4 - Roles and
Responsibilities
Included 150mm grinder in section 6,7 & 9
1 & 2 1 December 2009
2 Deleted 150mm and 180mm grinder in section 7,8 and 10
2 February 2011
3 Item 9 - Added polisher, and change the sentence to include Bosch unit Item 17 - Added reference to Bosch manual
2
4
August 2011
4 Item 14 on pages 3 & 4
Correct spelling of “Bosch” angle grinders and “Pferd” discs.
Added website to find more information on “Pferd” discs.
APPROVAL
POSITION NAME DATE SIGNATURE
Manager Reliability & Asset Management
