What are regulations for Pressure Relief System on ships ?

Note :

• Pressure relief valves are to be connected to the highest part of the cargo tank above deck level. Pressure relief valves on cargo tanks with a design temperature below 0 °C are to be arranged to prevent their becoming inoperative due to ice formation when they are closed. Due consideration is to be given to the construction and arrangement of pressure relief valves on cargo tanks subject to low ambient temperatures.

• Valves are to be constructed of materials with a melting point above 925 °C. Consideration of lower melting point materials for internal parts and seals shall be given if their use provides significant improvement to the general operation of the valve