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(a) General. Spray coating operations whenever practicable shall be confined to properly designed, constructed and adequately ventilated spray booths or spray rooms which meet all the requirements of both this section and Article 137.
(1) Mechanical ventilation shall be kept in operation at all times while spraying operations are being conducted and for a sufficient time thereafter to allow flammable vapors from drying coated articles and drying finishing material residue to be exhausted.
(2) When spray is automatically applied without an attendant constantly on duty, the operating control of spray apparatus shall be so arranged that spray cannot be applied unless exhaust fans are in operation.
(c) Exhaust and Make-Up Air.
(1) Air exhausted from spray operations shall not be recirculated. Safe arrangements should be provided for an adequate supply of make-up air to compensate for air exhausted from spraying operations.
(2) No means of heating make-up air shall be located in a spray booth.
(d) Dilution of Flammable Vapors. Ventilation in spray facilities shall be sufficient to dilute flammable vapors to less than 20 percent of their lower explosive limit as specified in Section 5416. Lower explosive limits of common solvents are listed in NFPA No. 49-1973, Hazardous Chemicals Data.
(e) Ventilation Rates. The velocity of air into all openings of a spray booth shall be not less than that specified in Table V-6.
TABLE V-6 MINIMUM MAINTAINED VELOCITIES INTO SPRAY BOOTHS Operating Conditions for Objects Completely Inside Crossdraft, Airflow Velocities, f.p.m. Booth f.p.m. Average Minimum Electrostatic and automatic airless operation.......... Up to 50 60 large booth 60 100 small booth 75 Air-operated guns, manual or automatic............... Up to 50 100 large booth 75 150 small booth 125 Air-operated guns, manual or automatic............... From 50 to 100 150 large booth 125 200 small booth 150
NOTE: A large booth is a walk-in size booth.
(f) Downdraft Booths.
Where downdraft booths are provided with doors, such doors shall be closed when spray painting.
(g) Respiratory Protection.
A spray booth operator is required to wear a respirator when he is positioned downstream from the object being sprayed. Respirator use shall conform to the requirements of Section 5144. (Title 24, T8-5153(a), (b), (c), (d), (e))
NOTE: Authority cited: Section 142.3, Labor Code.
1. New section filed 7-18-75; effective thirtieth day thereafter (Register 75, No. 29).
2. Editorial correction of subsection (a) (Register 76, No. 10).
3. Amendment filed 7-16-76; effective thirtieth day thereafter (Register 76, No. 29).