Washington Administrative Code › Title 296 - Labor and Industries, Department of › Chapter 296-24 - General safety and health standards › Part E - HAZARDOUS MATERIALS, FLAMMABLE LIQUIDS, SPRAY FINISHING › Hazardous Materials › Section 296-24-37003 - Spray booths

Current through Register Vol. 24-14, July 15, 2024
(1)
Construction.
Spray booths must be substantially constructed of
				  steel, securely and rigidly supported, or of concrete or masonry except that
				  aluminum or other substantial noncombustible material may be used for
				  intermittent or low volume spraying. Spray booths must be designed to sweep air
				  currents toward the exhaust outlet.
(2)
Interiors.
The interior
				  surfaces of spray booths must be smooth and continuous without edges and
				  otherwise designed to prevent pocketing of residues and facilitate cleaning and
				  washing without injury.
(3)
Floors.
You must cover the floor surface of a spray booth and
				  operator's working area, if combustible, with noncombustible material of such
				  character as to facilitate the safe cleaning and removal of residues.
(4)
Distribution or baffle
				  plates.
Distribution or baffle plates, if installed to promote an even
				  flow of air through the booth or cause the deposit of overspray before it
				  enters the exhaust duct, must be of noncombustible material and readily
				  removable or accessible on both sides for cleaning. Such plates must not be
				  located in exhaust ducts.
(5)
Dry type overspray collectors-(Exhaust air filters).
In
				  conventional dry type spray booths, overspray dry filters or filter rolls, if
				  installed, must conform to the following:
(a)
				  You must design, install, and maintain the spraying operations except
				  electrostatic spraying operations so that the average air velocity over the
				  open face of the booth (or booth cross section during spraying operations) is
				  not less than 100 linear feet per minute. Electrostatic spraying operations may
				  be conducted with an air velocity over the open face of the booth of not less
				  than 60 linear feet per minute, or more, depending on the volume of the
				  finishing material being applied and its flammability and explosion
				  characteristics. You must install visible gauges or audible alarm or pressure
				  activated devices to indicate or ensure that the required air velocity is
				  maintained. Dry spray booths equipped with a filter roll which is automatically
				  advanced when the air velocity is reduced to that specified in this section
				  should be arranged to cause shutdown of spraying operations if the filter roll
				  fails to advance automatically. Maintenance procedures should be established to
				  assure replacing filter pads before excessive restriction to airflow occurs.
				  Filter pads should be inspected after each period of use and clogged filter
				  pads discarded and replaced. You must inspect filter rolls to ensure proper
				  replacement of filter media.
(b)
				  You must immediately remove all discarded filter pads and filter rolls to a
				  safe, well-detached location or placed in a water-filled metal container and
				  disposed of at the close of the day's operation unless maintained completely in
				  water.
(c) The location of filters
				  in a spray booth must be so as to not reduce the effective booth enclosure of
				  the articles being sprayed.
(d) You
				  must protect space within the spray booth on the downstream and upstream sides
				  of filters with an approved automatic sprinkler system meeting one of the
				  following requirements:
(i) An automatic
				  sprinkler system as defined in WAC
				  296-24-607; or
(ii) A fixed dry chemical extinguishing
				  system as defined in WAC
				  296-24-622; or
(iii) A fixed carbon dioxide gaseous agent
				  system as defined in WAC
				  296-24-623.
(e) You must not use filters or filter rolls
				  when applying a spray material known to be highly susceptible to spontaneous
				  heating and ignition.
(f) Clean
				  filters or filter rolls must be noncombustible or of a type having a
				  combustibility not in excess of Class 2 filters as listed by Underwriters'
				  Laboratories, Inc. You must not alternately use filters and filter rolls for
				  different types of coating materials, where the combination of materials may be
				  conducive to spontaneous ignition. See also WAC
				  296-24-37013(6).