[Code of Federal Regulations]
[Title 29, Volume 8]
[Revised as of July 1, 2007]
From the U.S. Government Printing Office via GPO Access
[CITE: 29CFR1926.66]
[Page 176-182]
TITLE 29--LABOR
CHAPTER XVII--OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT
OF LABOR
PART 1926_SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION--Table of Contents
Subpart D_Occupational Health and Environmental Controls
Sec. 1926.66 Criteria for design and construction of spray booths.
(a) Definitions applicable to this section--(1) Aerated solid
powders. Aerated powders shall mean any powdered material used as a
coating material which shall be fluidized within a container by passing
air uniformly from below. It is common practice to fluidize such
materials to form a fluidized powder bed and then dip the part to be
coated into the bed in a manner similar to that used in liquid dipping.
Such beds are also used as sources for powder spray operations.
(2) Spraying area. Any area in which dangerous quantities of
flammable vapors or mists, or combustible residues, dusts, or deposits
are present due to the operation of spraying processes.
(3) Spray booth. A power-ventilated structure provided to enclose or
accommodate a spraying operation to confine and limit the escape of
spray, vapor, and residue, and to safely conduct or direct them to an
exhaust system.
(4) Waterwash spray booth. A spray booth equipped with a water
washing system designed to minimize dusts or residues entering exhaust
ducts and to permit the recovery of overspray finishing material.
(5) Dry spray booth. A spray booth not equipped with a water washing
system as described in paragraph (a)(4) of this section. A dry spray
booth may be equipped with
(i) Distribution or baffle plates to promote an even flow of air
through the booth or cause the deposit of overspray before it enters the
exhaust duct; or
(ii) Overspray dry filters to minimize dusts; or
(iii) Overspray dry filters to minimize dusts or residues entering
exhaust ducts; or
(iv) Overspray dry filter rolls designed to minimize dusts or
residues entering exhaust ducts; or
[[Page 177]]
(v) Where dry powders are being sprayed, with powder collection
systems so arranged in the exhaust to capture oversprayed material.
(6) Fluidized bed. A container holding powder coating material which
is aerated from below so as to form an air-supported expanded cloud of
such material through which the preheated object to be coated is
immersed and transported.
(7) Electrostatic fluidized bed. A container holding powder coating
material which is aerated from below so as to form an air-supported
expanded cloud of such material which is electrically charged with a
charge opposite to the charge of the object to be coated; such object is
transported, through the container immediately above the charged and
aerated materials in order to be coated.
(8) Approved. Shall mean approved and listed by a nationally
recognized testing laboratory.
(9) Listed. See ``approved'' in paragraph (a)(8) of this section.
(b) Spray booths--(1) Construction. Spray booths shall 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 shall be designed to sweep air currents toward
the exhaust outlet.
(2) Interiors. The interior surfaces of spray booths shall be smooth
and continuous without edges and otherwise designed to prevent pocketing
of residues and facilitate cleaning and washing without injury.
(3) Floors. The floor surface of a spray booth and operator's
working area, if combustible, shall be covered 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, shall be of
noncombustible material and readily removable or accessible on both
sides for cleaning. Such plates shall 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, shall conform to the following:
(i) The spraying operations except electrostatic spraying operations
shall be so designed, installed and maintained that the average air
velocity over the open face of the booth (or booth cross section during
spraying operations) shall be 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. Visible
gauges or audible alarm or pressure activated devices shall be installed
to indicate or insure that the required air velocity is maintained.
Filter rolls shall be inspected to insure proper replacement of filter
media.
(ii) All discarded filter pads and filter rolls shall be immediately
removed 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.
(iii) The location of filters in a spray booth shall be so as to not
reduce the effective booth enclosure of the articles being sprayed.
(iv) Space within the spray booth on the downstream and upstream
sides of filters shall be protected with approved automatic sprinklers.
(v) Filters or filter rolls shall not be used when applying a spray
material known to be highly susceptible to spontaneous heating and
ignition.
(vi) Clean filters or filter rolls shall be noncombustible or of a
type having a combustibility not in excess of class 2 filters as listed
by Underwriters' Laboratories, Inc. Filters and filter rolls shall not
be alternately used for different types of coating materials, where the
combination of materials may be conducive to spontaneous ignition.
(6) Frontal area. Each spray booth having a frontal area larger than
9 square feet shall have a metal deflector or curtain not less than 2
\1/2\ inches (5.35
[[Page 178]]
cm) deep installed at the upper outer edge of the booth over the
opening.
(7) Conveyors. Where conveyors are arranged to carry work into or
out of spray booths, the openings therefor shall be as small as
practical.
(8) Separation of operations. Each spray booth shall be separated
from other operations by not less than 3 feet (0.912 m), or by a greater
distance, or by such partition or wall as to reduce the danger from
juxtaposition of hazardous operations. See also paragraph (c)(1) of this
section.
(9) Cleaning. Spray booths shall be so installed that all portions
are readily accessible for cleaning. A clear space of not less than 3
feet (0.912 m) on all sides shall be kept free from storage or
combustible construction.
(10) Illumination. When spraying areas are illuminated through glass
panels or other transparent materials, only fixed lighting units shall
be used as a source of illumination. Panels shall effectively isolate
the spraying area from the area in which the lighting unit is located,
and shall be of a noncombustible material of such a nature or so
protected that breakage will be unlikely. Panels shall be so arranged
that normal accumulations of residue on the exposed surface of the panel
will not be raised to a dangerous temperature by radiation or conduction
from the source of illumination.
(c) Electrical and other sources of ignition--(1) Conformance. All
electrical equipment, open flames and other sources of ignition shall
conform to the requirements of this paragraph, except as follows:
(i) Electrostatic apparatus shall conform to the requirements of
paragraphs (e) and (f) of this section;
(ii) Drying, curing, and fusion apparatus shall conform to the
requirements of paragraph (g) of this section;
(iii) [Reserved]
(iv) Powder coating equipment shall conform to the requirements of
paragraph (c)(1) of this section.
(2) Minimum separation. There shall be no open flame or spark
producing equipment in any spraying area nor within 20 feet (6.08 m)
thereof, unless separated by a partition.
(3) Hot surfaces. Space-heating appliances, steampipes, or hot
surfaces shall not be located in a spraying area where deposits of
combustible residues may readily accumulate.
(4) Wiring conformance. Electrical wiring and equipment shall
conform to the provisions of this paragraph and shall otherwise be in
accordance with subpart S of this part.
(5) Combustible residues, areas. Unless specifically approved for
locations containing both deposits of readily ignitable residue and
explosive vapors, there shall be no electrical equipment in any spraying
area, whereon deposits of combustible residues may readily accumulate,
except wiring in rigid conduit or in boxes or fittings containing no
taps, splices, or terminal connections.
(6) Wiring type approved. Electrical wiring and equipment not
subject to deposits of combustible residues but located in a spraying
area as herein defined shall be of explosion-proof type approved for
Class I, group D locations and shall otherwise conform to the provisions
of subpart S of this part, for Class I, Division 1, Hazardous Locations.
Electrical wiring, motors, and other equipment outside of but within 20
feet (6.08 m) of any spraying area, and not separated therefrom by
partitions, shall not produce sparks under normal operating conditions
and shall otherwise conform to the provisions of subpart S of this part
for Class I, Division 2 Hazardous Locations.
(7) Lamps. Electric lamps outside of, but within 20 feet (6.08 m) of
any spraying area, and not separated therefrom by a partition, shall be
totally enclosed to prevent the falling of hot particles and shall be
protected from mechanical injury by suitable guards or by location.
(8) Portable lamps. Portable electric lamps shall not be used in any
spraying area during spraying operations. Portable electric lamps, if
used during cleaning or repairing operations, shall be of the type
approved for hazardous Class I locations.
(9) Grounding. (i) All metal parts of spray booths, exhaust ducts,
and piping systems conveying flammable or combustible liquids or aerated
solids shall be properly electrically grounded in an effective and
permanent manner.
(d) Ventilation--(1) Conformance. Ventilating and exhaust systems
shall be
[[Page 179]]
in accordance with the Standard for Blower and Exhaust Systems for Vapor
Removal, NFPA No. 91-1961, where applicable and shall also conform to
the provisions of this section.
(2) General. All spraying areas shall be provided with mechanical
ventilation adequate to remove flammable vapors, mists, or powders to a
safe location and to confine and control combustible residues so that
life is not endangered. Mechanical ventilation shall be kept in
operation at all times while spraying operations are being conducted and
for a sufficient time thereafter to allow vapors from drying coated
articles and drying finishing material residue to be exhausted.
(3) Independent exhaust. Each spray booth shall have an independent
exhaust duct system discharging to the exterior of the building, except
that multiple cabinet spray booths in which identical spray finishing
material is used with a combined frontal area of not more than 18 square
feet may have a common exhaust. If more than one fan serves one booth,
all fans shall be so interconnected that one fan cannot operate without
all fans being operated.
(4) Fan-rotating element. The fan-rotating element shall be
nonferrous or nonsparking or the casing shall consist of or be lined
with such material. There shall be ample clearance between the fan-
rotating element and the fan casing to avoid a fire by friction,
necessary allowance being made for ordinary expansion and loading to
prevent contact between moving parts and the duct or fan housing. Fan
blades shall be mounted on a shaft sufficiently heavy to maintain
perfect alignment even when the blades of the fan are heavily loaded,
the shaft preferably to have bearings outside the duct and booth. All
bearings shall be of the self-lubricating type, or lubricated from the
outside duct.
(5) Electric motors. Electric motors driving exhaust fans shall not
be placed inside booths or ducts. See also paragraph (c) of this
section.
(6) Belts. Belts shall not enter the duct or booth unless the belt
and pulley within the duct or booth are thoroughly enclosed.
(7) Exhaust ducts. Exhaust ducts shall be constructed of steel and
shall be substantially supported. Exhaust ducts without dampers are
preferred; however, if dampers are installed, they shall be maintained
so that they will be in a full open position at all times the
ventilating system is in operation.
(i) Exhaust ducts shall be protected against mechanical damage and
have a clearance from unprotected combustible construction or other
combustible material of not less than 18 inches (45.72 cm).
(ii) If combustible construction is provided with the following
protection applied to all surfaces within 18 inches (45.72 cm),
clearances may be reduced to the distances indicated:
(a) 28-gage sheet metal on 1/4-inch 12 inches (30.48 cm).
asbestos mill board.
(b) 28-gage sheet metal on 1/8-inch 9 inches (22.86 cm).
asbestos mill board spaced out 1 inch
(2.54 cm) on noncombustible spacers.
(c) 22-gage sheet metal on 1-inch rockwool 3 inches (7.62 cm).
batts reinforced with wire mesh or the
equivalent.
(d) Where ducts are protected with an
approved automatic sprinkler system,
properly maintained, the clearance
required in paragraph (d)(7)(i) of this
section may be reduced to 6 inches (15.24
cm).
(8) Discharge clearance. Unless the spray booth exhaust duct
terminal is from a water-wash spray booth, the terminal discharge point
shall be not less than 6 feet from any combustible exterior wall or roof
nor discharge in the direction of any combustible construction or
unprotected opening in any noncombustible exterior wall within 25 feet
(7.6 m).
(9) Air exhaust. Air exhaust from spray operations shall not be
directed so that it will contaminate makeup air being introduced into
the spraying area or other ventilating intakes, nor directed so as to
create a nuisance. Air exhausted from spray operations shall not be
recirculated.
(10) Access doors. When necessary to facilitate cleaning, exhaust
ducts shall be provided with an ample number of access doors.
(11) Room intakes. Air intake openings to rooms containing spray
finishing operations shall be adequate for the efficient operation of
exhaust fans and shall be so located as to minimize the creation of dead
air pockets.
[[Page 180]]
(12) Drying spaces. Freshly sprayed articles shall be dried only in
spaces provided with adequate ventilation to prevent the formation of
explosive vapors. In the event adequate and reliable ventilation is not
provided such drying spaces shall be considered a spraying area.
(e) Fixed electrostatic apparatus--(1) Conformance. Where
installation and use of electrostatic spraying equipment is used, such
installation and use shall conform to all other paragraphs of this
section, and shall also conform to the requirements of this paragraph.
(2) Type approval. Electrostatic apparatus and devices used in
connection with coating operations shall be of approved types.
(3) Location. Transformers, power packs, control apparatus, and all
other electrical portions of the equipment, with the exception of high-
voltage grids, electrodes, and electrostatic atomizing heads and their
connections, shall be located outside of the spraying area, or shall
otherwise conform to the requirements of paragraph (c) of this section.
(4) Support. Electrodes and electrostatic atomizing heads shall be
adequately supported in permanent locations and shall be effectively
insulated from the ground. Electrodes and electrostatic atomizing heads
which are permanently attached to their bases, supports, or
reciprocators, shall be deemed to comply with this section. Insulators
shall be nonporous and noncombustible.
(5) Insulators, grounding. High-voltage leads to electrodes shall be
properly insulated and protected from mechanical injury or exposure to
destructive chemicals. Electrostatic atomizing heads shall be
effectively and permanently supported on suitable insulators and shall
be effectively guarded against accidental contact or grounding. An
automatic means shall be provided for grounding the electrode system
when it is electrically deenergized for any reason. All insulators shall
be kept clean and dry.
(6) Safe distance. A safe distance shall be maintained between goods
being painted and electrodes or electrostatic atomizing heads or
conductors of at least twice the sparking distance. A suitable sign
indicating this safe distance shall be conspicuously posted near the
assembly.
(7) Conveyors required. Goods being painted using this process are
to be supported on conveyors. The conveyors shall be so arranged as to
maintain safe distances between the goods and the electrodes or
electrostatic atomizing heads at all times. Any irregularly shaped or
other goods subject to possible swinging or movement shall be rigidly
supported to prevent such swinging or movement which would reduce the
clearance to less than that specified in paragraph (e)(6) of this
section.
(8) Prohibition. This process is not acceptable where goods being
coated are manipulated by hand. When finishing materials are applied by
electrostatic equipment which is manipulated by hand, see paragraph (f)
of this section for applicable requirements.
(9) Fail-safe controls. Electrostatic apparatus shall be equipped
with automatic controls which will operate without time delay to
disconnect the power supply to the high voltage transformer and to
signal the operator under any of the following conditions:
(i) Stoppage of ventilating fans or failure of ventilating equipment
from any cause.
(ii) Stoppage of the conveyor carrying goods through the high
voltage field.
(iii) Occurrence of a ground or of an imminent ground at any point
on the high voltage system.
(iv) Reduction of clearance below that specified in paragraph (e)(6)
of this section.
(10) Guarding. Adequate booths, fencing, railings, or guards shall
be so placed about the equipment that they, either by their location or
character or both, assure that a safe isolation of the process is
maintained from plant storage or personnel. Such railings, fencing, and
guards shall be of conducting material, adequately grounded.
(11) Ventilation. Where electrostatic atomization is used the
spraying area shall be so ventilated as to insure safe conditions from a
fire and health standpoint.
(12) Fire protection. All areas used for spraying, including the
interior of the
[[Page 181]]
booth, shall be protected by automatic sprinklers where this protection
is available. Where this protection is not available, other approved
automatic extinguishing equipment shall be provided.
(f) Electrostatic hand spraying equipment--(1) Application. This
paragraph shall apply to any equipment using electrostatically charged
elements for the atomization and/or, precipitation of materials for
coatings on articles, or for other similar purposes in which the
atomizing device is hand held and manipulated during the spraying
operation.
(2) Conformance. Electrostatic hand spraying equipment shall conform
with the other provisions of this section.
(3) Equipment approval and specifications. Electrostatic hand spray
apparatus and devices used in connection with coating operations shall
be of approved types. The high voltage circuits shall be designed so as
to not produce a spark of sufficient intensity to ignite any vapor-air
mixtures nor result in appreciable shock hazard upon coming in contact
with a grounded object under all normal operating conditions. The
electrostatically charged exposed elements of the handgun shall be
capable of being energized only by a switch which also controls the
coating material supply.
(4) Electrical support equipment. Transformers, powerpacks, control
apparatus, and all other electrical portions of the equipment, with the
exception of the handgun itself and its connections to the power supply
shall be located outside of the spraying area or shall otherwise conform
to the requirements of paragraph (c) of this section.
(5) Spray gun ground. The handle of the spraying gun shall be
electrically connected to ground by a metallic connection and to be so
constructed that the operator in normal operating position is in
intimate electrical contact with the grounded handle.
(6) Grounding-general. All electrically conductive objects in the
spraying area shall be adequately grounded. This requirement shall apply
to paint containers, wash cans, and any other objects or devices in the
area. The equipment shall carry a prominent permanently installed
warning regarding the necessity for this grounding feature.
(7) Maintenance of grounds. Objects being painted or coated shall be
maintained in metallic contact with the conveyor or other grounded
support. Hooks shall be regularly cleaned to insure this contact and
areas of contact shall be sharp points or knife edges where possible.
Points of support of the object shall be concealed from random spray
where feasible and where the objects being sprayed are supported from a
conveyor, the point of attachment to the conveyor shall be so located as
to not collect spray material during normal operation.
(8) Interlocks. The electrical equipment shall be so interlocked
with the ventilation of the spraying area that the equipment cannot be
operated unless the ventilation fans are in operation.
(9) Ventilation. The spraying operation shall take place within a
spray area which is adequately ventilated to remove solvent vapors
released from the operation.
(g) Drying, curing, or fusion apparatus--(1) Conformance. Drying,
curing, or fusion apparatus in connection with spray application of
flammable and combustible finishes shall conform to the Standard for
Ovens and Furnaces, NFPA 86A-1969, where applicable and shall also
conform with the following requirements of this paragraph.
(2) Alternate use prohibited. Spray booths, rooms, or other
enclosures used for spraying operations shall not alternately be used
for the purpose of drying by any arrangement which will cause a material
increase in the surface temperature of the spray booth, room, or
enclosure.
(3) Adjacent system interlocked. Except as specifically provided in
paragraph (g)(4) of this section, drying, curing, or fusion units
utilizing a heating system having open flames or which may produce
sparks shall not be installed in a spraying area, but may be installed
adjacent thereto when equipped with an interlocked ventilating system
arranged to:
(i) Thoroughly ventilate the drying space before the heating system
can be started;
[[Page 182]]
(ii) Maintain a safe atmosphere at any source of ignition;
(iii) Automatically shut down the heating system in the event of
failure of the ventilating system.
(4) Alternate use permitted. Automobile refinishing spray booths or
enclosures, otherwise installed and maintained in full conformity with
this section, may alternately be used for drying with portable
electrical infrared drying apparatus when conforming with the following:
(i) Interior (especially floors) of spray enclosures shall be kept
free of overspray deposits.
(ii) During spray operations, the drying apparatus and electrical
connections and wiring thereto shall not be located within spray
enclosure nor in any other location where spray residues may be
deposited thereon.
(iii) The spraying apparatus, the drying apparatus, and the
ventilating system of the spray enclosure shall be equipped with
suitable interlocks so arranged that:
(a) The spraying apparatus cannot be operated while the drying
apparatus is inside the spray enclosure.
(b) The spray enclosure will be purged of spray vapors for a period
of not less than 3 minutes before the drying apparatus can be energized.
(c) The ventilating system will maintain a safe atmosphere within
the enclosure during the drying process and the drying apparatus will
automatically shut off in the event of failure of the ventilating
system.
(iv) All electrical wiring and equipment of the drying apparatus
shall conform with the applicable sections of subpart S of this part.
Only equipment of a type approved for Class I, Division 2 hazardous
locations shall be located within 18 inches (45.72 cm) of floor level.
All metallic parts of the drying apparatus shall be properly
electrically bonded and grounded.
(v) The drying apparatus shall contain a prominently located,
permanently attached warning sign indicating that ventilation should be
maintained during the drying period and that spraying should not be
conducted in the vicinity that spray will deposit on apparatus.
[58 FR 35149, June 30, 1993]