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Environmental Health & Safety Office
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THIS PROCEDURE APPLIES TO THE FORCIBLE APPLICATION OF AN ABRASIVE TO A SURFACE BY PNEUMATIC PRESSURE, HYDRAULIC PRESSURE, OR CENTRIFUGAL FORCE.
I. Personal Protective Equipment
A. Abrasive blasting respirators are continuous flow, air line respirators constructed so that they cover the head, neck and shoulders to protect from rebounding abrasives.
B. All abrasive blasting operators must wear respirators:
1. When using silica sand in manual blasting operations,
2. Where concentrations of other toxic dusts are present.
C. Dust-filter respirators may be used for outside abrasive-blasting operations where nonsilica abrasives are used on low toxic materials.
D. Operators must be equipped with heavy canvas or leather gloves and aprons or equivalent protection.
E. Safety shoes are mandatory when heavy pieces of work are handled.
F. Eye and face protection are required when the respirator design does not provide such protection for:
1. Abrasive-blasting operators
2. Any other personnel working in the vicinity
G. Use of respirators must be in compliance with the UNC Charlotte Respiratory Protection Program.
II. Air Supply
A. The air for abrasive-blasting respirators must be free of harmful qualities of dusts, or noxious gases.
B. Air must meet requirements for Grade D breathing air.
C. Compressors for supplying air should be breathing air type and:
1. Must be equipped with necessary safety and standby devices.
2. Must be constructed and situated to avoid entry of contaminated air.
3. Must have suitable in-line air purifying sorbent filters.
4. Must have alarms to indicate compressor failure and overheating.
D. Oil-lubricated compressors must have a high temperature and carbon monoxide alarm.
III. Mechanical Precautions
A. Machines and hoses are to be inspected frequently and all parts showing excessive wear should be repaired or replaced.
B. Nozzles are to be externally attached to the hose by a fitting which will prevent accidental disengagement.
C. Lengths of hose are to be joined by external metallic connectors.
D. A remote control “deadman” is to be provided.
E. A support is to be provided on which the nozzle may be mounted when it is not in use.
F. Pressure blast vessels are to be manufactured in accordance with the most recent edition of the ASME Boiler and Pressure Vessel Code.
IV. Housekeeping and Sanitation A. Good housekeeping practices are to be followed in abrasive blasting operation to prevent slips, trips, and falls.
B. A dust free area should be available for blasters to take breaks, eat lunch, wash hands etc. These activities should not be permitted in the blasting area.
C. Hoses that supply air to the blasting hood should not be placed where vehicles or movable equipment can cause damage.
V. Engineering and Administrative Dust Control Methods A. Substitution
1. If possible, substitutes with less health hazards than silica sand should be used.
2. Precautions are to be taken when substituting more expensive abrasive material for silica sand. An accumulation of toxic dust from paints and coating material may present an additional hazard when materials have been exhausted.
3. If there is no acceptable substitute for sand, then use the sand of maximum hardness that is pre-ready.All sand used for blasting is to be washed and graded. The largest size grade commensurate with job requirements is to be used.
B. Application
If practical blasting should be done with water injection to moisten the dust particles.
C. Isolation
1. A blasting zone (where dust is visible) should be established and marked off with signs around the perimeter of the area. Example of display sign stating:
CAUTION
2. Blasting should be done on an “ off Shift” when employees are least present. 3. Blasting is not permitted when the wind direction and velocity are at levels that cause the blasting dust to encounter people who are not protected.
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