Controlling Static Electricity in Powder Handling Operations

Static electricity is capable of causing many undesirable effects during powder handling operations. The types of industries affected by these problems include chemical, pharmaceutical, paints, coatings, food and beverage, and the extent of the problem ranges from small scale unreported incidents, right through to devastating explosions causing injury or fatalities, lost production through plant downtime and other financial costs to the business. In potentially explosive atmospheres, the amount of energy contained in spark discharges front plant, equipment and even people may be sufficient to ignite many fine dusts produced during handling loose solids such as powder, granules, pellets and flakes. The minimum energy required to ignite any given powder (MIE) depends on the fineness of the powder, with the lowest values tending to relate to very fine powder. If the MIE is above 1- J, and there are no flammable gases and vapours present, special measures to minimize static electricity are usually not necessary, however precautions could still be necessary with conductive plant and equipment capable of storing high levels of static charge, to minimize electric shock risks for operators.