In order to avoid the potential for paint booth fires and explosions, it is essential to pay particular attention to Paint Booths details on proper setup, cleaning and maintenance. Flammable liquids used in spraying include paints, resins, lacquers, paint removers and adhesives. Fire or explosions can occur due to the accumulation of vapors from spraying these flammable liquids and the presence of an ignition source like sparks from electrical equipment and naked flames from welding or cigarette smoking.
Tips to prevent fires and explosions
• Protective covers on sprinkler heads in the paint booth – in the form of either lightweight paper or plastic bags as protection from overspray. If the sprinklers are clogged with overspray, they may not work reliably in the event of a fire.
• Installation of a filter gauge – filters must be monitored routinely whether they require replacements. A filter gauge can be installed that will automatically shutdown the spray gun when the filter fails to allow a minimum amount of air to pass through.
• Proper maintenance of ventilation ducts – the general rule of thumb is to clean ventilation ducts and duct discharge points when the residue of overspray accumulates to about 1/8 inch in thickness.
• Interior cleaning must be done regularly – all surfaces inside the paint booth must be free from combustibles and overspray. The use of vacuum is not suggested because the motor may cause ignition of the combustibles.
• Use cleaning solvents with high flash points – cleaning solvents for the paint booth interior must contain flash points of no lower than 100oF to reduce the potential for fires.
• Ensure caution when mixing combustible coatings – sometimes, more than one type of combustible coating is used in the same booth that can spontaneously cause ignition. Before combustible coatings are changed, make sure that the paint booth is clean as well as the exhaust ducts.
• Paint booths should have enough space – spray booths must be placed at a minimum distance of three feet away from combustible walls, storage areas and other booths. This will prevent fire from spreading from the booth outwards.
How to minimize the risks of hazardous substances and spraying methods
One of the ways to reduce risks is through substitution meaning a less hazardous substance like water-based paint is used instead of solvent-based paint. Using a spray booth controls exposure and minimizes the risks of fires and explosions. The spray booth should:
• Be constructed with non-combustible materials like steel with a smooth finish
• Be without any ignition sources like unsealed lights inside the spray booth and within 2 meters from the open face of the booth
• Have effective air filters or a water wash system that will remove paint mist
• Have an airflow at the point of spraying of at least a half meter/second for side draught booths
• Have an exhaust stack that vents vertical discharge outside the building
The booth must always be operating during spraying and should continue to do so until all overspray has been removed for at least 5 minutes.