Simply put, powder coating involves the application of electrostatically charged dry powder particles to electrically grounded conductive (metal) objects and then applying heat to cure the powder onto the coated object. Powder coating materials are typically made up of electrically insulating resin (thermoset or thermoplastic polymer) and pigment. The advantages of powder coating compared to (wet) paint include the durability of the finish and the ability to reuse the over-sprayed powder. Today, powder coating is used in a variety of industries including automotive, appliances and construction.
It should be noted however, that the powders usually used in powder coating applications are explosible – meaning that if dispersed in air and subjected to an ignition source, are capable of creating a dust explosion. Both during powder spraying operations and in the downstream dust collection systems, formation of an explosible dust cloud can be expected. Of course, if there is an ignition source present, a dust deflagration or explosion may occur. One typical ignition source during powder coating operations is static sparks from inadvertently ungrounded metal objects that are being coated. It is therefore clearly essential that effective precautions are taken to control the risk and protect employees, contractors, the public and the facility against the effects of fires and explosions.