applicable OSHA standards for spray finishing operations

1. Spray
Finishing
Operations
Paint Booth

2. Objectives
• Assess spray booth operations for OSHA
compliance
• Identify occupational hazards associated with spray
booth operations
• Recognize applicable regulatory standards
• Apply compliance activities according to FOM

3. Spray Painting Injuries
• Subcontractors were critically injured due to a flash fire while
cleaning an enclosed paint booth.
• One worker received burns to over 80% of her body. She was
taken to a Medical Center where she had to undergo many
surgeries and skin grafts.
• The second employee received third degree burns to the arms
and face.

4. Potential Occupational Hazards
• Physical hazards include:
o Exposure to ignitable (flammable/combustible) liquids
o Explosive paint spray mists, particulates and vapors
o Accumulated paint spray residues
o Hazards from pressured equipment used in painting
operations because of its compressed air component.
o Electric shock and/or burns

5. Potential Occupational Hazards
• Potential health hazards (through inhalation or dermal
absorption) include exposure to:
o solid and liquid aerosols
o organic solvents and their vapors
o dermatitis and localized skin irritation
o Inhalation and absorption of organic solvent and vapors often
results in central nervous system (CNS) disorders. Some paint
pigments and additives are highly toxic, such as lead, cadmium and
chromium.

6. Hazard Controls
• Spray booths construction and installation must be in conformance
with the requirements of NFPA 33.
• Spray room/spray area is specifically designed for that purpose
o The room is protected with an automatic sprinkler system
o The room is separated vertically and horizontally from personnel
occupancies by at least two-hour (2) fire-resistant construction.
• The size of the spray booth or designated spray area must be large
(deep) enough to contain the largest object being coated. Sufficient
space must be provided to permit airflow on all sides of the object.

7. Hazard Controls
• All personnel involved in spray finish operations should
be trained and understand potential occupational
hazards, required operational process maintenance,
and emergency procedures
o NFPA 33 Chapter 18.1

8. Fire Prevention Key Points
• Paint spray operations may involve a fire potential, e.g., paint removal, solvent
wipe, and paint application using spray apparatus. Certain paints, lacquers,
varnishes, shellacs, solvents, and thinners are very flammable. Other materials,
under certain conditions, will burn violently.
• The use of solvents for cleaning operations shall be restricted to those having
flashpoints above 100oF.
• However, per 29 CFR 1910.107 when cleaning spray nozzles and auxiliary
equipment, you may also use solvents having flashpoints not less than those
normally used in spray operations.
• All cleaning shall be conducted inside spray booths with the ventilating equipment
operating.

9. Fire Prevention Key Points
• Portable fire extinguishers shall be provided at each paint spray operation area in
accordance with NFPA 10.
o The fire extinguishers shall be suitable to handle the most flammable of the
coating materials being used.
• Signs stating “NO SMOKING” or “NO OPEN FLAMES” shall be conspicuously
posted at all paint spray operation areas and paint storage rooms
• Sprinklers protecting spraying areas shall be protected from the accumulation of
residue from spraying operations.
o Per NFPA 33 sprinklers shall be permitted to be covered by cellophane bags
having a thickness of 0.08mm or less or by thin paper bags and shall be
replaced frequently so heavy deposits do not accumulate

10. Paint Spray Booth
• Separation of operations
o The use of spark-producing equipment shall be prohibited within
twenty (20) feet of a spray booth unless separated by a one (1) hour
fire rated partition.
o Spray booths shall be separated from other operations by at least
three (3) feet or by a (1) hour rated fire walls
• Hot surfaces.
o Heating appliances, steam pipes, and any other hot surfaces shall
not be placed in areas where deposits of flammable or combustible
residues may accumulate from spraying.

11. Paint Spray Booth
• Electrical wiring and equipment
o There shall be no open flame or spark producing equipment in any spraying area
or within twenty (20) feet unless separated by an approved partition.
o Electrical wiring/equipment that is not a subject to deposits of combustible
residues, but located in a spraying area shall be explosion-proof type approved
for Class I, Group D locations.
o An exception exists for wiring in rigid conduit, boxes, or fittings that do not
contain taps, splices, or terminal connections.

12. Paint Spray Booth
• Electrical wiring and equipment
o Portable lamps shall not be used in any spray booth during spraying
operations. If portable lamps are used during cleaning or repair
operations the lamps must be approved for Class I locations as
defined in NFPA 33 or NFPA 70, NEC.
o All metal parts of spray booths, exhaust ducts, and piping systems
that convey flammable liquids, combustible liquids, or aerated solids
shall be properly grounded in an effective and permanent manner.
o There are detailed specific requirements related to fixed electrostatic
apparatus.

13. Ventilation Systems
• Paint spray operation areas must be provided with
mechanical ventilation that meets NFPA 91 requirements,
“Standard for Exhaust Systems for Air Conveying of Vapors,
Gases, Mists, and Noncombustible Particulate Solids,” and is
adequate to remove flammable vapors, gases, or mists to a
safe location.
• The mechanical ventilation is purposed to confine and control
ignitable residues, so they do not present a fire or explosion
hazard.

14. Ventilation Systems
• The spray booths and spray rooms ventilating systems shall be
equipped with interlocks to prevent or stop the spray application
equipment from operating unless the exhaust ventilation system is
operating and functioning as designed.
• Mechanical ventilation shall be operated continuously during paint
spray operations and for a sufficient time after paint spray operations
have stopped in order to allow vapors from drying coated articles and
drying finishing material residue to be completely exhausted.
• Adequate conditioned make-up air shall be provided.

15. Ventilation Systems
• The design average air velocity into a spray booth must conform to
1910.94 Table G-10, and 1910.107
• Cross drafts must not exceed recommendations established by
these references (Up to 100 CFM). 1910.94, Table G-10

16. Ventilation Systems
• The total air volume exhausted through a paint spray booth shall
dilute vapors to at least 25 percent of the lower explosive limit (LEL)
of the paint/solvent being sprayed.

17. Ventilation Systems
• Visible gauges or audible alarms or pressure activated devices shall
be installed to indicate and to ensure that the required air velocity is
maintained.
• A pressure gauge shall be installed to show the pressure drop across
the filters, and the gauge shall be marked to show the pressure drop
at which the filters require cleaning or replacement.

18. Ventilation Systems
• Where the air supply to a spray booth/room is filtered, the fan
static pressure shall be calculated with the assumption that
the filters are dirty and require either cleaning or
replacement.
Refer to 29 CFR 1910.94 for detailed spray booth ventilation design and construction specifications.
Air make up
- Temperature
- Volume of air
- Filtered air
Air make up

19. Ventilation Systems
• Ventilation exhaust
o Permits are required
The exhaust fan is the heart
of every spray booth
Exhaust working chamber

20. Ventilation Systems
Ventilation exhaust construction
• Exhaust ducts shall be constructed of steel
• Protected against mechanical damage
• Properly supported
• Have a separation of at least 18 inches from combustible
materials.
o If dampers are installed, they shall be maintained so that they
will be always in a fully open position the ventilating system is
in operation.

21. Ventilation Systems
• Ventilation exhaust
o Each spray booth shall have an independent exhaust duct
system that discharges to the exterior of the building.
o 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.

22. Ventilation Systems
• Ventilation exhaust
o The design of the exhaust stack must conform with
all state and local building and environmental
codes.
o In the District of Columbia, exhaust must be
vertically discharged upwards, and each stack
height must be at least 15 feet high and 5 feet
above the roof.

23. Ventilation Systems
• Ventilation exhaust
o Air exhaust from spray operations shall be directed so
that it will not contaminate make-up air being introduced
into the paint spray operation area or other ventilation
intakes.
o Unless the spray booth exhaust duct terminal is from a
water-wash spray booth, the terminal discharge point
shall be at least 6 feet from any combustible exterior wall
or roof.

24. Ventilation Systems
• Ventilation exhaust
o Where a paint spray booth receives make-up air
through self-closing doors, dampers, or louvers, they
shall be fully open at all times when the booth or room is
in use for spraying. The velocity of air through the doors,
dampers, or louvers shall not exceed 200 feet per
minute.

25. Ventilation Systems
• Ventilation exhaust
o Make-up air to paint spray booths shall be provided.
o The make-up air shall be clean, fresh air, free of
contamination from nearby industrial exhaust systems.
o Make-up air shall be supplied to spray booths/rooms in a
quantity equal to the volume of air exhausted from the
booth/room.

26. Ventilation Systems
• Ventilation exhaust
o The replacement air during the heating seasons shall be
maintained at not less than 65oF at the point of entry into
the paint spray booth. Temperature shall be regulated as
provided in ANSI Z9.2-2001 when otherwise unheated
make-up air would be 10oF below room temperature.
o Heating make-up air shall not be permitted from inside a
spray booth.

27. Electrical Equipment
• Electrical wiring and electrical utilization equipment that is
used in the spray area or in the vicinity of the spray area shall
meet the requirements of NFPA 70, National Electrical Code,
Article 500, and all applicable requirements stipulated in
NFPA 33, “Spray Application Using Flammable and
Combustible Materials.”

28. Electrical Equipment
• No employee shall install or modify any electrical wiring in
areas where spray operations occur.
• Electric motors for exhaust fans must not be placed inside
booths or ducts.

29. Electrical Equipment
• NFPA 33, 1995 edition, Spray Application Using Flammable
or Combustible Materials, paragraph 5-2, which requires that
"each spray area be provided with mechanical ventilation that
is capable of confining and removing vapors and mists to a
safe location and is capable of confining and controlling
velocity

30. What is a Spray Booth? 1910.107(a)(3)
• A power-ventilated structure
• Constructed to enclose or accommodate a spraying
operation
• Purposed to confine and limit the escape of spray,
vapor, and residue
• Designed to safely conduct or direct them (the spray,
vapor and residue) to an exhaust system.

31. Spray Booth Types
• Generally, two recognized spray booth types
o Water Wash Spray Booth
o Dry Spray Booth

32. Water Wash Spray Booth 107(a)(4)
• A spray booth equipped with a water washing
system
o The filtration method uses water instead of
dry filters
o Designed to minimize dusts or residues
entering exhaust ducts, and to permit the
recovery of overspray finishing material
https://youtu.be/gH0R8OO9jAM (the first 2min)

33. Commonly Used Water Treatment Additives
• Denaturants
o Separate the paint overspray and the water
o Make it easy to remove the paint from the water
o Reduces the down time

34. Commonly Used Water Treatment Additives
• Biocides
o Removes smell that water and overspray may
cause
o Prevents bacterial build up
o Prevents bacterial contamination

35. Commonly Used Water Treatment Additives
• Antifoam agents
o To stop the paint from foaming up
o Especially important if using water-based paints
o Allows proper water treatment
o Maintains correct water levels

36. Hazards of Water Treatment Additives
• Occupational safety and health risks of:
o Exposure to highly corrosive substances
o Potential for legionnaires disease

37. Hazard Prevention of Water Wash Spray
Booth
• Routine maintenance
o To prevent bacterial and fungal growth
- Hazards associated to housekeeping of sludge accumulation (??belongs here?/?
- Possible videos …..
- https://youtu.be/7MCYh82Q0wc (this is advertising no-words video)
- https://youtu.be/8x5QPttg3ZI (this is another advertising no-words video with a water wash spray
booth and drying area)
- https://youtu.be/PB8EH1HhJ0Y (this is advertising no-words video a close look of water wash with a
spraying demonstration)
- https://youtu.be/gGSaXkmsWSE (this is advertising no-words video of multiple water wash booths)
- https://youtu.be/aK8XyviYKlQ (this is advertising no-words video of water wash and spraying
demonstrating the exhaust system. Maybe usable if we can modify and remove the individual
demonstrating)

38. Dry Spray Booth Types 107(a)(5)
• A spray booth not equipped with a water washing
system

39. Dry Spray Booth Types 107(a)(5)
• Spray booths are defined by the type of airflow they
use to collect overspray.
o Open front booths are not fully enclosed. There are three
walls and a ceiling contain the overspray and fumes, and a
fan in the back wall draws room air past the work area and
out through an exhaust filter.

40. Dry Spray Booth Types 107(a)(5)
• Conventional
o Crossflow are fully enclosed booths using a
horizontal stream of air to collect fumes and
particles. An intake filter on one side cleans
incoming air, and an exhaust filter cleans it again
before it's vented outside the booth.

41. Dry Spray Booth Types 107(a)(5)
• Semi down draft
• Down draft • Side draft

42. Dry Spray Booth Types 107(a)(5)
• Downdraft booths are fully enclosed just like crossflow
booths. However, incoming air is drawn through ceiling
mounted filters. There are several variations on the
downdraft design: some use pits below the floor to draw
air straight down, while others use "semi downdraft" or
"side downdraft" designs that pull incoming air down
and to the sides or back of the booth.

43. General Paint Booth Regulations
• Spraying and finishing areas should be posted with
clearly visible signage reading “NO SMOKING”
o 1910.107(g)(7) and NFPA 33 10.11
• Smoking and open flames should be prohibited in
any spray finishing area
o NFPA 1 and NFPA 33

44. General Paint Booth Regulations
• A sufficient supply of portable fire extinguishers
should be closely located and available anywhere
near all spraying operations. 1910.107(f)(4)
• Metal waste cans with self-closing lids should be
provided wherever rags or waste are soaked with
finishing materials. All soaked rags or waste should
be deposited in metal waste cans immediately
after being used. NFPA 1 and NFPA 33

45. Spray Booth Construction
• Spray booths should be constructed with non-
combustible material securely and rigidly supported
(steel, concrete or similar masonry) or covered with
non-combustible material.
o 1910.107(b)(1) and NFPA 101 Chapter 5.1
• All spray booth baffle plates (grates) should be
constructed with noncombustible material.
o 1910.94(c)(3)(iii)

46. Spray Booth Construction
• 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.
1910.107(b)(3) and NFPA 33 Chapter 5.1.2

47. Spray Booth Construction
• Each spray booth having a frontal area larger than 9
square feet shall have a metal deflector or curtain not
less than 2½ inches deep installed at the upper outer
edge of the booth over the opening. 1910.107(b)(6)

48. Spray Booth Construction
• Spray booths interiors should be designed to be
continuously smooth and without edges to prevent
accumulation of residues.
o 1910.107(b)(2) and NFPA 5.1
• Spraying operations and booths should be separated
from other operations by at least three (3) feet in
space, or by a suitable partition or wall.
o 1910.107(b)(8) NFPA33 5.3

49. Spray Booth Construction
• Spray booths should be installed so that all portions
are readily accessible for cleaning.
o NFPA 1 and NFPA 33 5.3.1

50. Spray Booth Construction
• Baffle plates if purposed 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.
o Such plates shall not be in exhaust ducts.
1910.107(b)(4)

51. Spray Booth Construction
• Spraying area should be illuminated through glass
panels or other translucent materials. Only fixed
lighting should be used as a source of illumination
o 1910.107(b)(10) and NFPA 6.9
• When it comes to lighting, regulatory agencies
require that booth light fixtures be approved for Class
I, Division II, Groups A-D.

52. Spray Booth Construction
• Spray booth accessories
o Turntables
o Draft gauges
o Spray booth scrapers
o Conveyor systems
o Spray gun rack and shelf
o Interlocks
o 1910.94() and 1910.107()

53. Spray Booth Construction
• All motors, wiring and lighting fixtures that are not
separated by a partition and located within twenty
(20) feet from spray finishing operations should be
explosion proof.
o 1910.94(c)(3) and 1910.107(c)(6) and NFPA 33 6.2.6

54. Spray Booth Construction
• Spray booth interiors should be protected with an
automatic sprinkler system.
o 1910.107(b)(5)(iv) and 1910.107(h)(12)
• Fire sprinkler heads should be kept free of
accumulated deposits
o 1910.107(f)(3)
(include diagram or photo)

55. Spray Booth Construction
• All hot surfaces (such as steam pipes, appliances
and space heaters) should be located away from
spray-finishing operations.
o 1910.107(c)(3)
All metal parts of spray booths, exhaust ducts and
piping systems should be permanently and
effectively grounded.
o 1910.107(c)(9)(i)

56. Operations and Maintenance
• Spray booth interiors should be free from
accumulated deposits prior to operation. Combustible
coverings i.e. plastic, thin paper, etc. and strippable
coatings can be used to facilitate cleaning operations
o 1910.107(b)(2) and 1910.107(g)(2)
All tools used for scraping residues and debris
should be non-sparking.
o 1910.107(g)(2)

57. Operation and Maintenance
• All residue scrapings and debris should be
immediately removed from the premises and
disposed of properly.
o 1910.107(g)(3)
• All cleaning solvents should be restricted to those
with flash points above 100oF
o 1910.107(g)(3) (find an example of cleaning solvent with flash point above 100oF and
include to the receiving and storage workshop)

58. Operation and Maintenance
• Approved metal cans with self closing lids should
be maintained wherever rags or waste are
impregnated with ignitable finishing materials and
disposed of daily
o 1910.107(g)(3) and NFPA 33 Chapter 10.5.1

59. Operation and Maintenance
• Clothing contaminated with spray material should
be kept off premises overnight or stored in metal
lockers.
o 1910.107(g)(3) and NFPA 33 10.6

60. Operation and Maintenance
• Cleaning operations using flammable or combustible
solvents inside spray booths should be conducted
with ventilation equipment operating during the
cleaning process.
o NFPA 33

61. Operation and Maintenance
• All spray booth overspray filters should be routinely
inspected, cleaned and replaced.
o 1910.94(c)(3)(iii)(a)
• All spray booth filters discarded at the end of the day
unless maintained completely in water.
o 1910.107(b)(5)(i)
o 1910.107(b)(5)(ii)
2/11/2008 Letter of interpretation (include hyperlink?)
(include link to UL class 2 filters cert)

62. Operation and Maintenance
• Spray booths shall not be alternately used for
different types of coating materials, where the
combination of the materials may be conducive to
spontaneous ignition, unless all deposits of the first used
material are removed from the booth and exhaust ducts
prior to spraying with the second used material.
1910.107(g)(6)

63. Flammable and Combustible Liquids
Handling
• Only one day’s worth of flammable or combustible
liquids should be kept near spray finishing
operations.
o 1910.107(e)(2)
• All flammable and combustible liquids must be
transported in either closed containers, approved
portable tanks, approved safety cans or closed pipes.
• 1910.107(e)(3)

64. Flammable and Combustible Liquids
Handling
• All flammable and combustible liquids in containers
larger than 60 gallons should be transported by
means of an approved pump.
• 1910.107(e)(4)

65. Flammable and Combustible Liquids
Handling
• All containers or pipes attached to flexible hoses
must have shut off valves at their connections.
o 1910.107(e)(6)(i)
• When flammable liquids are transferred from one
container to another, both containers should be
grounded and bonded.
• 1910.107(e)(6)(iv)

66. Flammable and Combustible Liquids
Handling
• All containers supplying spray nozzles should be a
closed type or provided with a metal cover.
• NFPA 33
• If flammable or combustible liquids are supplied to
spray nozzles by positive displacement pumps, the
discharge pressure should be preventing from
exceeding the operating pressure of the system.
o NFPA 33

67. Flammable and Combustible Liquids
Handling
• Containers supplying spray nozzles by gravity flow
should be less than ten (10) gallons.
• NFPA 33
• Containers supplying spray nozzles resting on
floors, or noncombustible supports should be
suspended by wire cables.
• NFPA 33

68. Ventilation Requirements
• Spraying areas must be provided with mechanical
ventilation that is kept in use during operation
o 1910.107(d)(2)
• Cleaning operations using flammable or combustible
solvents inside spray booths should be conducted
with ventilation equipment operating during the
cleaning process.
o NFPA 33

69. Ventilation Requirements
• Spraying operations should have sufficient
ventilation to maintain individual exposure within
acceptable limits.
o 1910.94(c)(4)(iii)
• Spray booths should be designed to sweep air
currents towards exhaust outlets.
o 1910.107(b)(a)

70. Ventilation Requirements
• All exhaust ventilation systems should be well
constructed and in good working order prior to
operation.
o 1910.94(a)(5),(6),(7)
• The average velocity of airflow intake through the
face of the spray booth should be at least 100 feet
per minute.

71. Ventilation Requirements
• 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.
o 1910.107(b)(5)(i) and 1910.94(c)(6)(i)

72. Ventilation Requirements
• Where fixed electrostatic atomization is used the
spraying area shall be so ventilated as to insure safe
conditions from fire and health standpoint
o 1910.107(h)(11)

73. Ventilation Requirements
• Air velocity assurance such as
o Visible gauges or audible alarm or pressure activated
devices shall be installed to indicate that the required
air velocity is maintained.
https://youtu.be/c40wPbtFz5M
https://youtu.be/a8_yUciGKko
https://youtu.be/yjNC4tp4N0M

74. Ventilation Requirements
• Calibrating a Manometer
o Fill the manometer with the fluid (often red) that comes with the tool.
o With the spray booth off, adjust the manometer to read zero by turning the
knob on the side of the manometer.
o Start the ventilation with clean filters and observe the rise of the manometer
reading. This reading should be marked with a green arrow. It represents that
there is no resistance to the air flow through the spray booth filters. Add .30 to
.50 to this reading (depending on the spray booth filter manufacturer’s
recommendation) and mark this reading with a red arrow. This reading
represents when the spray booth filters are dirty or loaded and need
replacing. When you reach the red arrow, it’s time to replace the filters.

75. Ventilation Requirements
• Clean and freshly make up air should be supplied to
the area to replace the volume of air exhausted
through the spray booth.
• Note: If outdoor temperature is less than 55oF, make up
air must be heated. 1910.94(c)(7)(i)

76. Ventilation Requirements
• All spray booths must have independent exhaust
stacks that direct outside the spray booth
environment. 1910.107(d)(3)

77. Ventilation Requirements
• Spray booth exhaust duct terminals must be
located at least six (6) feet from any combustible
exterior wall or roof and prevented from discharging
in the direction of any combustible construction.
o 1910.107(d)(8)
• Spray booth exhaust air should be directed so that
it will not contaminate makeup air or create a
measurable nuisance to the spray environment.
o 1910.107(d)(9)

78. Ventilation Requirements
• All exhaust ducts should be fitted with access
doors for cleaning.
o 1910.107(d)(10)
• Freshly spray-finished items and articles should be
set to dry in areas with adequate ventilation.
• If not, these areas should be treated as spray areas and
subject to all similar regulatory requirements.
o 1910.107(d)(12) and 1910.107(j)(1) and NFPA 86A-1969

79. Ventilation Requirements
• No prohibition if drying without surface temperature
increase.
o 1910.107(j)(2) and NFPA 33 13.1.2
• The ventilation system shall maintain the concentration
of vapors below 25% of the LEL

80. Ventilation System Construction
• All fan-rotating elements should be constructed of
non-ferrous or non-sparking materials. 1910.107(d)(4)
• Electric motors driving the exhaust fans should be
placed outside of booths and ducts. 1910.107(d)(5)
• Belts and pulleys in ducts used to drive the fan
blades should be thoroughly enclosed. 1910.107(d)(6)

81. Knowledge check?
• Scenario: Spraying water-based coating that has some toxic properties. Air
monitoring indicates no overexposures to employees. Use approximately 18
gallons of coating per week
• Question? Should the determination whether to perform the spray operation in a
booth be based on the employee’s level of exposure to the hazardous chemicals
in the paint or the mere presence of a hazardous chemical in the paint?
• Answer: Spray booths or spray finishing rooms are to be used to enclose or
confine all spray finishing operations “…This standard is intended to protect the
health of personnel from injurious effects of contact with gases, vapors, mists,
dusts, or solvents used in, created, released, or disseminated by spray finishing
operations…” ANSI Z9.3-1971
o 1910.94(c) and OSHA Interpretation dated March 28, 2008

82. Electrostatic Apparatus
• Only approved electrostatic equipment should be
used in connection with paint-spraying operations.
o 1910.107(h)(2) and NFPA 33
• Transformers, power packs, control apparatus and all
other electrical portions of the equipment should be
located outside of the spraying or vapor areas
o Exception: High voltage grids and electrostatic
atomizing heads.
o NFPA 33 and 1910.107(h)(3)

83. Electrostatic Apparatus
• Include Video
Include photos or videos (bell/rotational atomizer)
Electrostatic atomization

84. Electrostatic Apparatus
• A space of at least twice the sparkling distance
must be maintained between painted items and
fixed electrodes, electrostatic atomizing heads or
conductors.
o Note: A suitable sign stating the sparking distance
should be posted near the assembly.
o NFPA 33 and 1910.107(h)(6)
o Note to self: How could CSHOs check to verify this? Just
make sure there is a sign?

85. Electrostatic Apparatus
• Electrostatic apparatuses should be equipped with
automatic controls that operate without time delay
to disconnect the power supply to the high voltage
transformer as well as signal to the operator any of
the following conditions:
o Ventilating equipment fails or ventilation fans stop
o Conveyors carrying items past high-voltage grid stops.
o The primary voltage input to the power supply de-
energizes
o A ground or imminent ground occurs at any point of the
high voltage system. NFPA 33 and 1910.107(h)(9)

86. Electrostatic Apparatus
• All insulators should be kept clean and dry.
o NFPA 33 and 1910.107(h)(5)
• Signs should be posted designating the process
zone as hazardous i.e. with respect to fire.
o NFPA 33

87. Electrostatic Apparatus
• Adequate booths, fencing, railing or guards should
be placed around the equipment to safely isolate
their process from storage and persons.
o Note: Railings, fencing and guards should be
adequately grounded, constructed of conducting
material and spaced at least five (5) feet from the
processing equipment.
o NFPA 33 and 1910.107(h)(10)

88. Electrostatic Apparatus
• Fixed electrostatic should not be used for any
goods being manipulated by hand during coating!
o 1910.107(h)(8)

89. Handheld Electrostatic Equipment
107(i)(1)
• 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.
o 1910.107(i)(2)

90. Handheld Electrostatic Equipment
• Only approved electrostatic hand spray apparatus shall
be used.
o 1910.107(i)(3)
• High voltage circuits shall not produce a spark of
intensity to ignite any vapor-air mixtures nor shock
hazard upon meeting a grounded object under all
normal operating conditions.
o MIE for flammable vapors and gasses are < 1 mJ
o MIE for combustible dusts can be as low as a few mJ

91. Handheld Electrostatic Equipment
• 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.
o 1910.107(i)(3)
Include video or photos

92. Handheld Electrical Support Equipment
• Transformers, powerpacks, control apparatus, and all
other electrical portions of the equipment shall be
located outside of the spraying area
o 1910.107(i)(4)
o Note: The handgun itself and its connections to the power
supply are excepted.

93. Handheld Electrostatic Spray Gun
• The spraying gun handle shall be:
o Electrically connected to ground by a metallic connection
o Designed so that the operator in normal operating position
is in intimate electrical contact with the grounded handle.
o 1910.107(i)(5) and NFPA 33

94. Objects in the Electrostatic Spray Area
• All electrically conductive objects in the spraying area
shall be adequately grounded.
o This requirement shall apply to paint containers, wash
cans, and any other objects or devices in the area.
o The equipment shall carry a prominent permanently
installed warning regarding the necessity for this
grounding feature.
o 1910.107(i)(6)

95. Handheld Electrostatic Equipment
Grounding Maintenance
• Objects being painted or coated shall be maintained in
metallic contact with the conveyor or other grounded
support.
• Hooks shall be regularly cleaned to ensure this contact
and areas of contact shall be sharp points or knife
edges where possible.
o 1910.107(i)(7)

96. Handheld Electrostatic Equipment
Interlocks & Ventilation
• 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.
o 1910.107(i)(8)

97. Handheld Electrostatic Equipment
Interlocks & Ventilation
• The spraying operation shall take place within a spray
area which is adequately ventilated to remove solvent
vapors released from the operation.
o 1910.107(i)(9) and NFPA 33 Chapter 12 Handheld electrostatic
spray equipment

98. Paint Booth Regulations Definitions
• Approved: Verified and listed by a NRTL.
• Bonded: The permanent joining of metallic parts to
form an electrically conductive path that will assure
electrical continuity and the capacity to conduct safely
current likely to be imposed.
• Combustible: Any liquid having a flashpoint at or
above 100oF but below 200oF.
• Flammable: Any liquid having a flashpoint below
100oF.
o NFPA 33

99. Ignition Sources Exemptions
• Automobile undercoating spray operations in
garages, where adequate natural or mechanical
ventilation using undercoating materials like kerosene
(UL fire hazard rating 30-40) or using only solvents
listed as having a flash point in excess of 100 °F.
o 1910.107(k)

100. Ignition Sources Exemptions
• Automobile undercoating in garages are exempt if
adequate natural or mechanical ventilation,
undercoating materials are not more hazardous than
kerosene, materials use solvents with flash point over
100oF, and there are no open flames or ovens within
twenty (20) feet.
o 1910.107(k) and NFPA 33 14.1

101. Organic Peroxides and Dual Component Coatings
• All spraying operations involving the use of organic peroxides
and other dual component coatings shall be conducted in
approved sprinklered spray booths meeting the requirements of
this section.
• Smoking shall be prohibited, and "No Smoking" signs shall be
prominently displayed, and only non-sparking tools shall be used
in any area where organic peroxides are stored, mixed or
applied.
o 1910.107(m)(1) and 1910.107(m)(2)

102. Spray Finishing Scope
• Applies to flammable and combustible finishing materials when
applied as a spray by compressed air, “airless” or “hydraulic
atomization,” steam, electrostatic methods, or by any other
means in continuous or intermittent processes. The section
also covers the application of combustible powders by powder
spray guns, electrostatic powder spray guns, fluidized beds, or
electrostatic fluidized beds. The section does not apply to
outdoor spray application of buildings, tanks, or other similar
structures, nor to small portable spraying apparatus not used
repeatedly in the same location.
o 1910.107(n)

103. Ventilation for Spray Finishing Operations
1910.94 or 1910.107
• The standard for ventilation of spray finishing operations 29 CFR
1910.94(c), was derived from ANSI Z9.3-1964, Design, Construction, and
Ventilation of Spray Finishing Operations. Therefore, 29 CFR §1910.94 and
its source standard, ANSI Z9.3, have the purpose of protecting employees
from health hazards associated with spray finishing operations, whereas 29
CFR §1910.107 and its source standard, NFPA 33, address the explosion
and flammability hazards of these operations. As a result, if there are health
hazards associated with vehicle body lining operations, such as exposure to
di-isocyanates, then it is possible that, even though a spray booth or room
would not be required because of an employer's compliance with NFPA 33-
2003, the presence of the health hazard would still necessitate a spray booth
or room as required by 29 CFR §1910.94(c).

104. NFPA 33
• Standard is intended to provide requirements for fire safety.
Only fire and explosion hazards are addressed, not toxicity.
NFPA covers 18 chapters of standards applicable to spray
finishing as well as appendices A-E.
• According to a federal OSHA interpretation, if a state or local
public safety agency or official, such as a fire marshal, enforces
the NFPA 33 requirements for electrical safety, ventilation, and
fire protection, your client would have to comply with them if
they were equivalent to, or more protective than 1910.107.

105. Standards that apply to Spray Finishing
• 1910.94(c) – Ventilation (based on ANSI Z9.3-1970)
• 1910.107 – Spray Finishing Using Ignitable Liquids (Flammable and
Combustible Materials)
• NFPA 33-1969
• 1910.307 – Hazardous (Classified) Electrical Locations
• NFPA 33- 2007 – Spray Application Using Flammable and Combustible
Materials
• NFPA 70-1990 2005 – National Electrical Code (NEC)
• ANSI/AIHA Z9.3-1994 – Spray Finishing Operations – Safety Code for Design,
Construction, and Ventilation

106. Spray Finishing Operation Definitions
• The employment of methods wherein organic or inorganic materials
are utilized in dispersed form for deposit on surfaces to be coated,
treated, or cleaned.
• Spray finishing can be conducted in a spray booth, spray room, or
spray area.

107. Spray Finishing Operation Definitions
• A spray booth is 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.
o 1910.94(c)(1)(ii)

108. Spray Finishing Operation Definitions
• A spray room is a room in which spray-finishing operations
not conducted in a spray booth are performed separately
from other areas.
o 1910.94(c)(1)(iii)
• A spraying area is 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.
o 1910.107(a)(2)

109. Spray Finishing Operation Definitions
• An exhaust ventilation system is a system for removing
contaminated air from a space, comprising two or more of
the following elements:
 enclosure or hood,
 duct work,
 dust collecting equipment,
 exhauster, and
 discharge stack.
o 1910.107(a)(2)

110. Difference between Spray Booth and Spray
Room
• Based on the definitions provided and the wide range of
spray booth sizes, and under certain conditions, spray booth
and a spray room could be treated as same.
• For example, in most cases where the employee could
enter the face of the booth?
• Spray room, spray booth, interior of exhaust plenum or duct,
and areas is direct path of spray are spray areas.

111. Housekeeping
• Sprinklers free of deposits.
• Walls free of paint residues
• Filter maintained clean from overspray
• Baffle booths
• Fan and V belt
o 1910.107()

112. Physical hazards
1. Struck by from high speed particles
2. High pressure hazards from air/water hoses
3. Static electricity shock from high speed particles
4. Abrasions, lacerations, loss of an eye or body part from high
pressure
5. Slip, trip and fall while maneuvering sand blasting equipment
Control measures:
1. Engineering Controls
2. Personal protective equipment
3. Work practices

113. Safe Work Practices
1. Never point a paint spray gun at any part of the body.
2. High pressure hazards from air/water hoses
3. Static electricity shock from high speed particles
4. Abrasions, lacerations, loss of an eye or body part from high
pressure
5. Slip, trip and fall while maneuvering sand blasting equipment
Control measures:
1. Engineering Controls
2. Personal protective equipment
3. Work practices

114. Work Practices
High volume low pressure (HVLP) spray guns maintain a 75 %
transfer efficiency at a reduced working pressure.
Not disconnecting the gun from the fluid hose or the hose from the
pump until the pressure has been released from the hose.
When maneuvering equipment hold the gun by the grip and remove
fingers from the trigger to avoid inadvertent equipment pressure
activation.
Routinely inspect all connections and fittings .
Routinely inspect all hoses for weak or worn spots connections and
fittings.

115. Engineering Controls
Paint spray guns shall be equipped with trigger guards and a
safety lock. The lock must be in the non-operating position except
when the gun is in use.
The