Safety evaluation of anti-static flexible intermediate bulk container having non-conductive inner bag

In order to prevent fire and explosion hazards due to electrostatic discharges when unloading powder from a flexible intermediate bulk container (FIBC), a variety of anti-static FIBCs, some include an inner bag, were tested using a full scale experimental apparatus. The effectiveness of conductive, low-resistance and conductive fibre threaded FIBCs were investigated. The last FIBC with or without a non-conductive inner bag was found to be effective for reducing charge accumulation not only on the body itself but also on the content discharging from it. It was also clarified that the surface charge density being generated on a non-conductive inner bag during an emptying operation can reach about 100 mu C/m(2) which meets the condition for a propagating brush discharge (250 mu C/m(2)) to occur. However, no evidence of such a discharge was found to occur.