Newson Gale’s latest series of articles that contain case studies of fires and explosions caused by static electricity draw attention to the wide range of processes that are susceptible to electrostatic charge generation and accumulation on portable and fixed plant equipment.
This case study investigates the factors behind the ignition of a combustible dust cloud during a manual powder processing operation. In this example a process operator was tasked with manually tipping approximately 18 kg (40 lbs) of powder from a plastic drum, constructed from polyethylene, into a metal process vessel. The plastic drum contained a combustible powder that had a minimum ignition energy of 12 milli-joules. A metal chime was positioned around the circumference of the top of the plastic drum to provide it with impact protection from daily usage in the plant.