failure of basic process control system (BPCS) loop may initiate overfilling of storage tanks. Often overfill of storage tanks cause fire and production loss. Of BPCS initiate an overfill of a storage tank which has three IPLs in place, what would be the frequency of consequence (overflow causing fire and production loss) THe IPLS are 1) Dike, 2) human action with 40 min response, and 3) underground drainage system