Current through Register 2024 Notice Reg. No. 38, September 20, 2024
(a) Blast-Cleaning Enclosures.
(1) Blast-cleaning enclosures shall be
exhaust ventilated in such a way that a continuous inward flow of air will be
maintained at all openings in the enclosure during blasting operations. It is
recommended that the following minimum ventilation rates as prescribed in the
appendix of ANSI Z9.4-1968, Ventilation and Safe Practices of Abrasive Blasting
Operations be used:
(A) Blast-cleaning
cabinet, 500 feet per minute calculated on the free opening without the
curtains.
(B) Rotary blast-cleaning
tables, 200 feet per minute calculated on the free opening without
curtains.
(C) Blast-cleaning rooms,
300 feet per minute at air inlets.
(2) In blasting enclosures, safety glass
protected by screening or equivalent shall be used in observation windows where
hard abrasives are used. All access openings in blast-cleaning enclosures shall
be designed, inspected regularly, and maintained when needed, in order to
prevent escape of dust. Blast-cleaning room doors shall be flanged and tight
when closed and shall be operable from both inside and outside.
(3) In installations when the abrasive is
recirculated, an abrasive separator shall be provided for the removal of fines
from the spent abrasive.
(4)
Abrasive blasting enclosures shall not be opened until visible airborne dust
has been removed by the exhaust system.
(b) Personal Protective Equipment.
(1) Abrasive blasting or equivalent
respirators shall be worn by employees under the following conditions:
(A) Inside blasting rooms during
operations.
(B) During continuous
blasting operations where concentrations of dust dispersed by abrasive blasting
operations may exceed limits prescribed in Section
5155.
(C) During continuous blasting operations
where silica sand is used as the blasting abrasive or when toxic materials are
blasted. Dust-filter respirators may be used for periods up to two hours per
shift, providing the concentrations of silica dust do not exceed ten times the
time-weighted, eight-hour exposure limit as specified in Section
5155. Use of respiratory protective
equipment is prescribed in Section
5144.
(2) Equipment for protection of the eyes and
face shall be worn by the operator when the respirator design does not provide
such protection and by any other personnel working in the vicinity of abrasive
blasting operations.
(c)
Organic Abrasives. Organic abrasives which are combustible shall be used only
in automatic systems. Where flammable or explosive dust mixtures may be
present, the construction of the equipment, including the exhaust system and
all electric wiring, shall conform to the requirements of Section
5174 and the Electrical Safety
Orders, Title 8, California Administrative Code. (Title 24, T8-5151(a),
(c))
1. New
section filed 7-18-75; effective thirtieth day thereafter (Register 75, No.
29).
2. Amendments filed 7-16-76; effective thirtieth day thereafter
(Register 76, No. 29).
Note: Authority cited: Section
142.3, Labor
Code.
