HEALTH AND SAFETY
Health and safety risks: The main risks involved in powder coating arise from the possibilities of dust explosion, fire electric shock, exposure to hazardous materials, compressed air etc.
Dust explosion and fire hazards: Processes which involve mixing air and combustible organic powders can be dangerous. A dust explosion may take place when both:
1) The concentration of powder in the air is above the lower explosive limit (LEL)
2) A source of ignition with the required degree of energy is present at the dust cloud; such sources of ignition can be hot surfaces, open flames, electrical or electrostatic discharges.
A fire can occur when a layer of deposited powder material or a powder cloud comes in contact with an ignition source mentioned in b) above. This type of fire can result in an explosion.
Thermosetting powders are only hazardous when within a certain range of powder-air mixture concentrations. In a well designed and operated powder coating plant these concentrations can only occur within the spraying and recovering system and this is therefore taken into account in their design.
Ignition temperature for usual powder-air concentrations is very high. A typical epoxy powder ignition temperature is approximately 500° C.
Electrical hazards: The main sources of electrical hazard are:
1) Improper or defective grounding systems that may lead to the build-up of electrostatic electricity and subsequent sparking or shock
2) Broken-down or overheated electrical equipment that could lead to fire or shock.
Exposure to hazardous materials: Powder coating materials contain many different components. Some of these substances may, depending upon the formulation, present a health hazard to the operating personnel, but only if they are allowed to escape into the working area because of improper handling or insufficient ventilation.
A particularly hazardous component in the powder coating material, if any, must be indicated by the supplier of the material on the product label and on the provided `Safety Data Sheet’ (SDS). Guidance will be included on the `Workplace Exposure Limits’ (WEL) and the precautions will be indicated which have to be taken in case of skin contamination or respiratory inhalation.