Spray painting and varnishing processes carry a significant risk of fire. Overspray deposited on fan blades, filters, and ducting in spray booths is flammable and contributes to the quick spread of any fire. Spray booths that are maintained on a regular basis and have an automatic sprinkler system that is professionally installed and maintained can successfully control this hazard.
Here are some guidelines for properly ensuring adequate levels of fire protection in a spray booth.
Providing Sufficient Fire Suppression and Protection
The interior of the spray booth, the space behind the filters, and the interior of the exhaust duct should all be protected by automatic sprinkler systems. If there is appropriate city water pressure and flow, the local water supply can be used as the water source for the booth in non-sprinklered buildings, or an alternate system can be developed. For the best solution, consult with a local fire suppression contractor, as sprinkler systems should be inspected annually by a professional.
Inspecting and Maintaining Sprinklers
Your sprinkler system should be inspected and maintained on a regular basis. Sprinkler systems might be delayed or stop completely due to poor upkeep. This failure might cause fire and smoke to spread outside the booth, causing significant destruction to nearby areas. Therefore, the following steps should be taken at a minimum:
- Examine the sprinkler heads throughout all spray booths for overspray residue buildup. Sprinkler heads are engineered to turn on at a specified temperature, and residue prevents the head from activating.
- Replace any heads that have been coated or painted with new sprinkler heads per the manufacturer’s instructions and safeguard the new sprinklers against further buildup by wrapping them with cellophane bags or thin paper bags.
- To prevent the accumulation of residue, inspect the coverings at regular intervals and replace them as needed.
The following steps should be followed to provide adequate ventilation:
- Install a ventilation system in all spray areas to safely remove flammable or combustible vapors/mists and keep the proportion of flammable or combustible vapors/mists in the surrounding air below 25% of the Lower Flammable Limit (LFL).
- Make sure the spray booth filters are securely fastened to their mountings.
- Overspray deposits in ducting are difficult to remove and can significantly increase a fire load, allowing it to spread quickly. Therefore, filters should be replaced according to the instructions provided by the manufacturer.
Proper Construction and Maintenance of a Booth
Follow these guidelines regarding the construction and upkeep of a booth:
- Noncombustible materials must be used to build the spray booth.
- To avoid residue pocketing and make ventilation, cleaning, and washing more manageable, the inner surfaces should be smooth.
- Clean the interior of the spray booth regularly with solvents with flashpoints above 100 degrees Fahrenheit and non-sparking scrapers and equipment to lower the fire load.
- While cleaning, operate the ventilation system in the booth.
- Moisten the scraped-off overspray residue, place it in UL or Factory Mutual (FM) listed or FM authorized metal waste containers, and remove it from the building as soon as possible.
- Electrical components should be approved for usage in Class I or Class II Division 2 locations, depending on their intended use.
- In places where flammable or explosive substances, solvents, or adhesives are used, sprayed, or stored, you must prohibit smoking and post “No Open Flames” and “No Smoking” signs.