New bulletin, if you have clients with spray finishing facilities - get in here! Great information!

1. Technical services risk bulletin
ISSUE 4
NOVEMBER 2012
SPRAY FINISHING
INTRODUCTION
iNSIDE THIS ISSUE:
Spray finishing is one of the most common severe hazards in
RELATIVE HAZARDS OF SPRAY industry. Because of its prevalence, it is often neglected as a
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FINISHING hazard. The National Fire Code of Canada (NFC) references
“Spray Coating Processes” in Part 5; Hazardous Processes and
USE OF WATER-BASED
2 Operations; under Section 5.4; Special Processes Involving
PRODUCTS
Flammable and Combustible Liquids. The NFC directly
references NFPA 33, “Spray Application using Flammable or
CONSTRUCTION 2 Combustible Materials”.
This technical bulletin provides an overview of Spray Finishing
VENTILATION 2 requirements. Storage and handling of flammable and
combustible liquids are regulated by the NFC Part 4 and NFPA
EXHAUST DUCTS 2 30 and are not covered in this bulletin.
Most spray booths seen in smaller operations are of the
FILTERS 3 prefabricated type. Larger or customized applications would
typically require a custom designed spray finish booth meeting
SOURCES OF IGNITION 3 the objectives and functional requirements as referenced in
NFPA 33.
ELECTRICAL REQUIREMENTS 4 relative hazards of spray finishing
COMBUSTIBLES 4 The finishing material is atomized by a spray gun nozzle or
applicator to produce a stream of fine droplets which creates a
SAFETY DEVICES 4 film on the item. Often paint is “thinned” by adding a solvent or
“thinner”.
FIRE PROTECTION 4
A great deal of the paint often misses the object (known as
“overspray”). If not controlled, this accumulates on surfaces
where the carrier evaporates leaving a combustible residue.
Often a fire in a spray area will be a flash fire of flammable
vapours followed by a secondary fire involving combustible
residues. Water-based products still leave combustible residue
as “overspray” when dried.
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2. use of water-based products ventilation
The industry standard is to use NFPA Standard No. 33 A proper ventilation system with proper fan size is required.
to analyse spray applications unless other ordinances are
enforced in the “jurisdiction of authority”. A fan motor should not be inside a duct or located in an
area subject to accumulation of residue unless listed for such
Construction applications (normally fan motors are not).
Construction of spray booths should preferably be of
smooth sheet steel construction with all parts being non-
combustible.
Masonry or concrete construction is allowed however
the rough surface of these materials allows for the
accumulation of combustible residue.
The floor of a spray booth should be made of a non-
combustible, non-sparking material.
exhaust ducts
Exhaust ducts should be provided for booths with filters.
Buildings with combustible construction should have
exhaust duct extending 1.8m (6ft) beyond the exterior
wall of building.
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3. filters Sources of ignition
Dry baffles: There should be no smoking, open flames, spark
producing equipment or exposed surfaces exceeding the
Tilted baffle plates change the air direction in the booth. ignition temperature of the material being sprayed within
This causes the paint to deposit on the baffles rather than 6.1m (20ft) of any spraying area and no arc or gas
go through the openings between them. The baffle plates welding within 15.2m (50ft).
are removed for cleaning. This type of system is 70%
effective. The Canadian Electrical Code is law in Canada. It
should be used in making recommendations on electrical
Dry filters: equipment for all hazardous locations including in and
around spray booths.
May be in the form of removable filter pads or
mechanically advanced filter rolls. This type of system is
approximately 80% efficient.
Water Wash:
A constant stream of water flows down a steel curtain
at the back of the booth. Overspray passes through
this water on the way through ventilation system. Water
extracts droplets and washes them into a tank where they
are filtered out.
This type of system is 90 to 95% effective.
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4. Electrical requirements combustibles
There are complex electrical requirements which depend A clearance of 0.9m (3ft) should be provided to nearby
on the type of material being sprayed, type of spray combustibles.
room or booth (i.e. open or enclosed), vertical and
horizontal distances to electrical equipment, etc. Ductwork should have a clearance of 457mm (18”) to
combustibles through roof and extend a minimum of 1.8m
Sealed light fixtures are required. (6ft) above the roof.
Fan motor must be kept outside duct and booth. safety devices
Ventilation equipment should be interlocked with spray
equipment.
fire protection
Automatic sprinkler protection or fixed extinguishing
systems.
A portable fire extinguisher located near each booth.
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5. risk management services
corporate headquarters office Location
150 Commerce Valley Drive, West
Markham, ON L3T 7Z3
For additional copies, please contact:
Bernadette Corless
E-mail: bernadette.corless@scm.ca
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