The use of FIBCs are not without their risks and when filling and emptying FIBCs
in hazardous areas, electrostatic charge can accumulate on both the contents (product) and the fabric of the material itself. It is common under these circumstances for the rates at which static electricity charges are generated to exceed the rates at which the charges can relax, allowing the accumulation of a static charge to develop within the process. The danger to plant personnel and the surrounding environment is if the charge is released in the presence of a flammable atmosphere, an ignition can occur. Since
many products are combustible, the inherent electrostatic discharge hazard from the material cannot be overlooked. Mitigating the potential risk of an electrostatic ignition is of paramount importance.
This case study explores the factors behind the ignition source of a static discharge during an FIBC unloading operation and what actions could have been taken to prevent serious site incidents.
As grounding wasn’t achieved, the charge was allowed to accumulate. Had grounding been accomplished via a Type C bag with either passive (single pole clamp and cable) or through active means (monitoring systems), connection to a true earth ground would have been verified and charge subsequently dissipated.