Spray Coating Operations
This guideline applies ONLY to spray coating operations conducted within an approved spray booth AND in a low hazard industrial occupancy.
In low hazard industrial occupancies, where spray coating operations are confined within a spray booth, and where an automatic sprinkler or fire suppression system is provided as specified in Sentence (3) to protect the spray booth, exhaust ducts and spraying area, the spraying area need not be separated from the remainder of the building.
An automotive repair shop may be classified as a “low hazard industrial occupancy” when the quantity of flammable liquids is limited and kept within an approved storage facility.
Low hazard industrial occupancy means an industrial occupancy in which the combustible content is not more than 50 kg/m2 or 1 200 MJ/m2 of floor area.
Construction
Spray booths shall be constructed and maintained in the following manner:
· A spray booth shall consists of a steel frame covered with sheet steel having a minimum thickness of 1.14 mm or be of equivalent non-combustible construction.
· The interior surfaces of a spray booth shall be kept smooth and continuous.
· The floor of a spray booth and the operators' working areas shall be of non-combustible material. Do not cover the floor area with paper or cardboard.
· A spray booth shall be provided with an over-spray collector (filters) to prevent a build-up of combustible deposits on the exhaust fan and ductwork. Do not spray without the filters being firmly in place.
The owner is cautioned to maintain the construction standard of the spray booth and not make non-approved additions or alterations to the accepted booth design.
Baffles
· Spray booth baffle plates shall be of a non-combustible material and be removable or arranged to facilitate cleaning.
· Spray booth baffle plates shall not be located in exhaust ducts.
Filters <remove if not applicable>
· Filters in ducts used to ventilate spray booths shall be made from non-combustible material or have a rate of combustibility no greater than Class II filters conforming to CAN4-S111-M, "Fire Tests for Air Filter Units."
· Filters shall be specifically approved for use with the material being sprayed.
· Filters shall not be used when applying spray material that is highly susceptible to spontaneous ignition. Consult the spray booth manufacturer for specific guidance.
· All discarded filter pads and filter rolls shall be removed to a safe location or placed in a water-filled metal receptacle and disposed of after each day's operation.
Blowers
· Fan blades and casings in exhaust blowers for spray booths shall be non-ferrous, or the fan shall be constructed so that a movement of the wheel or shaft will not permit 2 ferrous parts of the fan to rub or strike together. Ensure that the factory supplied and approved fan blade is used and maintained in the exhaust duct.
Ventilation
· Mechanical ventilation with sufficient air movement to prevent dangerous flammable vapour or powder concentrations shall be provided in all spraying areas. The Fire Department shall inspect and approve the spray area prior to initial use.
Air Velocity
· Where a mechanical exhaust ventilation system with horizontal air movement is provided in a spray booth, the air velocity at the face of the spray booth shall be not less than 0.5 m/s (100 feet per second) for non-electrostatic spraying, or 0.3m/s (60 feet per second) for electrostatic spraying.
· The air velocity can be checked by dividing the fan cfm by the square foot area of the booth opening and multiplying by 0.8 . The results should meet or exceed the expected velocity identified above. Replace the fan, to provide the required cfm as needed.
Exhaust Ducts
· A separate exhaust duct shall be provided for each spray booth, except that a common duct is permitted to be used if it serves spray booths having a combined open frontal area of not more than 1.7 square metres. This will be reviewed on the initial Fire inspection.
Air Exhausted
· Generally, air exhausted from spray operations shall not be returned to the building.
Exhaust Ducts
· Exhaust ducts for spray booths shall be kept securely supported.
· Duct material shall be of sheet steel of the same gage thickness and quality as the manufacturer approves. Repairs shall incorporate acceptable material as required.
· Generally, a clearance of 450 mm shall be maintained between exhaust ducts for spray booths and unprotected combustible material. Where exhaust ducts pass through combustible roofs or partitions, a clearance of not less than 100 mm between the duct and combustible material shall be provided by metal collars, and sealed with non-combustible insulating material.
· Check the clearance provided around your duct and any combustible materials or roof assembly. Make corrective repairs as required.
· Exhaust ducts for spray booths shall be provided with access doors for cleaning purposes. Do not cover over duct access openings.
· The exhaust outlet to atmosphere from all spray booths shall be not less than 1.8 m from any combustible exterior wall or roof, and located so that air does not discharge toward any combustible surface or unprotected opening within 7.5 m of the exhaust outlet. Ensure that that exhaust duct outlet is not altered to reduce the clearances.
Electrical Equipment
· All electrical equipment within the spraying area, including lighting fixtures, shall conform to CSA C22.1, "British Columbia Electrical Safety Act and Pursuant Regulations." Changes to electrical equipment within 3 metres of any spray booth opening needs to be reviewed by the Fire Department, prior to changes.
· Electric motors for exhaust fans shall not be placed inside spray booths or ducts.
· Electrical devices and attachments, not specifically approved or listed for use within the spray booth atmosphere, shall not be used within the booth, or within 3 metres of any booth opening.
· All metal parts of spray booths, exhaust ducts and piping systems conveying flammable liquids or combustible liquids shall be electrically bonded and grounded.
Flammable and Combustible Liquids
· Flammable liquids and combustible liquids for use in spraying areas shall be stored and handled in an acceptable manner, and at no time shall the amount of flammable liquids and combustible liquids in the spraying areas exceed one day's supply. Contact the Fire Department to determine the safe method of storage and handling of flammable liquids. The Fire safety Plan shall be modified to include all safety provisions.
· Flammable liquids and combustible liquids shall be kept in closed containers when not in use.
· Class I liquids shall be dispensed only from containers conforming to ULC/ORD-C30, "Safety Containers,"
· Where Class I liquids are supplied to spray nozzles by positive displacement pumps, the pump discharge line shall be provided with a suitable relief valve discharging to the pump suction or to a “safe” remote location. Contact the Fire Department to determine and approve such “safe” remote location.
Control of Fire Hazards
· The spraying equipment for a spray booth shall be interlocked to prevent operation when the ventilation system is shut down, or the circulating water pump of a water-wash booth is shut down. Do not bypass any safety interlocks!
· Where flammable liquid or combustible liquid finishes are being applied in a spray booth, combustible residue shall be removed from the spraying area and put in acceptable waste receptacles. Do not use cleaning tools or aids which will create sparks or heat when used to remove over spray.
Waste Receptacles
· Greasy or oily rags or materials subject to spontaneous ignition shall be deposited in a acceptable receptacle or be removed from the premises.
· An acceptable receptacle shall be constructed of non-combustible materials (metal), have a close-fitting metal cover, and if the flooring material upon which it is placed is combustible, have a flanged bottom or legs not less than 50 mm high.
· An acceptable receptacle shall not be placed closer than 1 m to combustible materials.
· Space-heating appliances, steam pipes and other hot surfaces shall not be located in an area subject to accumulation of deposits of combustible residue from spray coating operations.
· Smoking, open flames or spark-producing devices shall not be permitted in a spraying area, and signs shall be posted. Signs prohibiting smoking shall have black lettering not less than 50 mm high with a 12 mm stroke on a yellow background, except that symbols of not less than 150 mm by 150 mm are permitted to be used in lieu of lettering.
Fire Protection
· Portable extinguishers shall be installed near all spraying areas. The fire extinguishers shall have at least a “40-B” rating. The maximum travel distance from any point in the spray area to the portable fire extinguisher shall be 9 metres (30 feet). Fire extinguishers shall be installed in the path of travel to an exit. Additional fire extinguishers may be required to satisfy the travel distance requirements.
· Sprinklers in spray booths shall be protected against over-spray residue with lightweight paper or thin polyethylene bags which shall be replaced before they have accumulated excessive deposits.
· Fusible links used to activate a fire suppression system in spray booths shall be protected against over-spray residue with lightweight paper or thin polyethylene bags which shall be replaced before they have accumulated excessive deposits. (cont’d)
Fire Protection (continued)
· Fire suppression system nozzles in spray booths shall be protected against over-spray residue with lightweight paper, thin polyethylene bags or manufacturer’s protective caps, which shall be replaced before they have accumulated excessive deposits.
· Generally, spray booths or other enclosures used for spraying operations shall not be used for drying by any arrangement which could cause an increase in the surface temperatures of such spray booths or enclosures.
· Generally, drying or curing equipment that utilizes open flames or that produces sparks shall not be installed in or near a spraying area.
· Drying equipment is permitted to be installed in an area adjacent to the spraying area provided the adjacent area is equipped with a ventilating system arranged to:
· purge the drying space before the heating system can be started,
· maintain a safe atmosphere at any source of ignition, and
· automatically shut off the heating system if the ventilating system is shut down.
· Spray booths are permitted to be used for drying operations provided:
· the spray booth conforms to Subsection 5.6.1. (Industrial Ovens) The Fire Department will need to inspect the facility an approve the systems prior to use as a drying operation.
· the interior of the enclosure is kept free of over-spray deposits,
· if portable drying apparatus is used, it is of the electric infrared type ONLY, and such apparatus, wiring and connections are removed from the enclosure during spraying operations, and
· interlocks are installed to
· prevent the use of spraying apparatus while the drying operation is taking place,
· provide for the purging of the enclosure of spray vapours for not less than 3 min before the drying apparatus can be energized,
· ensure that the ventilating system maintains a safe atmosphere within the enclosure during the drying process, and
· ensure that the drying apparatus will automatically shut off if the ventilating system is shut down.
Flammable Gases
· No vehicle or apparatus equipped with a vessel containing a Class 2.1 flammable gas shall be permitted in a drying oven, or exposed to any heat source or ambient temperature conditions that could cause over-pressurization of the vessel.
Electrostatic Spray Coating and Detearing
· Except for high voltage grids and their connections, all electrical components including transformers, power packs and control equipment for electrostatic spray coating or for the electrostatic removal of excess coating material shall be located in an area where the vapour concentration of flammable liquids or combustible liquids cannot exceed 25% of the lower explosive limit. Fire Department inspection and approval is required prior to initial use.
· Electrostatic spraying and detearing equipment shall be provided with automatic controls that will operate without a time delay to disconnect power to high voltage transformers and to signal the operator when
· stoppage of the air supply, ventilating fan or the conveyor system occurs,
· there is a ground at any point on the high voltage system, or
· clearances are reduced below a space equivalent to twice the sparking distance.
· All insulators shall be kept clean and dry.
· A space equivalent to twice the sparking distance shall be maintained between articles being painted or deteared and electrodes or conductors.
· A sign shall be posted near an electrical assembly stating the maximum sparking distance.
· Drip plates and screens subject to paint deposits shall be removable for cleaning.
· All high voltage components including atomizing heads shall be insulated and protected against mechanical damage and accidental contact or grounding.
· High voltage circuits shall be designed so that any discharge occurring will not ignite vapour-air mixtures or create a shock hazard.
· An automatic means shall be provided for grounding the electrode system when it is de-energized.
· All electrically conductive objects in the spraying area shall be grounded, and a sign shall be posted indicating the need for such grounding.
· Articles being electrostatically spray coated shall not be held by hand nor shall they be suspended in such a manner as to reduce the proper operating distance from the atomizing heads.
· Electrostatic spraying equipment shall be located not less than 1.5 m from processing equipment and shall be isolated from other areas by grounded guards and fences of electrically conducting material.
· The surface temperature of equipment in a spraying area shall not exceed 66°C.
· The energy supply to the hand spray gun shall be controlled by a switch that also controls the coating material supply.
· The spray gun handle shall be grounded and shall have a metallic connection which is in direct contact with the operator's hand during spraying.
· Spray Residue: Hooks and other supports for sprayed articles shall be kept clean and free of paint.