When analyzing the possibility of over pressure in equipment, possibility of utility failure should be carefully considered. can result in over pressure in related equipments. Utility failureįailure of utilities such as electricity, instrument air, steam, fuel, cooling water etc. The extra flow coming as a result of valve opening should be relieved in this case to protect the equipment. This flow can drive the equipment pressure upto design pressure of the upstream high pressure source.
Inadvertent opening of valves located at high pressure sources upstream to the protected equipment can result in over pressure in the equipment. The normal inlet flow in this case in this case should be considered as the minimum relieving flowrate. This pressure build-up can go as high as the design pressure of upstream pumps or compressors combined with the height of the liquid column upstream. If the fluid still continues to flow into the equipment, absence of an outlet for this fluid results in fluid accumulation and build-up of pressure. This case refers to closure of a valve on the outlet of equipment (vessel, heat exchanger etc).
