Abstract: Safety relief and cooling system should be allocated for a storage tank of flamable and explosive LPG so as to prevent explosion when a fire takes place. The said systems are two related safety precautions. LPG storage tanks should be provided with fully—open safety valves which are sealed with springs. The simplified equation for relief valves of LPG storage tanks is got based on the formula sited in "Vessel Safety Technical Inspection Regulation" issued by China National Labor Ministry and also based on the related content of "Fire Protection Specification of Architectural Design". The following requirements are put forward for the allocation of relief tubes for safety valves. The supports of relief tubes should be firm enough because the gas flow speed gets higher in the tubes due to the high gas flow speed at the nozzels when relief valves are in operation. Vent risers should be provided with a flame arresters and lightening protection groundings. The relief system should be kept unblocked all the time.