Sets construction, electrical, ventilation and equipment requirements for spray finishing with flammable or combustible materials on construction sites. Paragraph (a) defines terms such as spraying area, spray booth, waterwash and dry booths, fluidized and electrostatic fluidized beds, and approved (listed by an NRTL). Booths are built of steel, concrete or masonry (aluminum or other noncombustible material only for intermittent or low-volume work), designed to sweep air toward the exhaust, with smooth interiors, noncombustible floor covering where the floor is combustible, and removable noncombustible baffle plates kept out of ducts. With dry filters, average face velocity must be at least 100 feet per minute (60 for electrostatic spraying), shown by gauges, alarms or pressure devices; used filters are removed immediately to a safe detached place or a water-filled metal container; sprinklers protect both sides of the filters; filters are not used with materials prone to spontaneous ignition, must be noncombustible or no worse than UL class 2, and are not alternated between incompatible coatings. Booths with a frontal area over 9 square feet carry a metal deflector at least 2 1/2 inches deep; conveyor openings are kept small; booths sit at least 3 feet from other operations or behind a partition, with 3 feet of clear space around them; lighting through glass panels uses only fixed units behind noncombustible, isolating panels. Ignition control: no open flames or sparking equipment in or within 20 feet of a spraying area unless partitioned; no heaters or hot surfaces where residue collects; wiring per Subpart S; only conduit or tap-free boxes where residue deposits, Class I Division 1 explosion-proof equipment elsewhere in the spraying area, and non-sparking Class I Division 2 equipment within 20 feet; enclosed guarded lamps within 20 feet; no portable lamps while spraying and only Class I approved ones for cleaning; all metal booth parts, ducts and piping grounded. Ventilation follows NFPA 91-1961 and must remove vapors, mists or powders during spraying and for long enough afterward; each booth has its own exhaust to the outside (shared exhaust allowed for identical-material cabinet booths totaling no more than 18 square feet); multiple fans are interlocked; fan elements are nonsparking; motors stay outside booths and ducts; steel ducts keep 18 inches from combustibles (reducible to 12, 9 or 3 inches with the specified protective linings, or 6 with maintained sprinklers); discharge terminals, other than from water-wash booths, are at least 6 feet from combustible walls and not aimed at combustible construction within 25 feet; exhaust air is never recirculated; drying spaces without adequate ventilation count as spraying areas. Fixed electrostatic apparatus must be approved, keep electrical parts outside the spraying area, insulate and guard electrodes, ground automatically when de-energized, keep goods on conveyors at least twice the sparking distance away (with a posted sign), never be used with hand-manipulated goods, cut power automatically on ventilation or conveyor stoppage, grounding faults or reduced clearance, be fenced with grounded conductive guards, and have automatic sprinklers where available, or other approved automatic extinguishing equipment. Electrostatic hand guns must be approved and non-igniting, energized only by the material-supply switch, grounded through the handle, interlocked with ventilation, with all conductive objects (paint containers and wash cans included) grounded and a permanent warning on the equipment about that grounding. Drying, curing or fusion equipment follows NFPA 86A-1969; booths are not used alternately for drying that heats them, flame or spark heating units sit outside the spraying area with interlocked ventilation, and auto refinishing booths may use portable infrared dryers only with interlocks that purge the booth for at least 3 minutes before energizing, Class I Division 2 equipment within 18 inches of the floor, grounding and a permanent warning sign.
The graph holds this control, the 0 it maps to, and the evidence behind each claim, over MCP and REST.