Sch 1 para 39 Characteristics of materials
(1) With regard to the characteristics of materials, the maximum pressure and temperature to be taken into consideration at the planning stage are the expected pressure during an explosion occurring under extreme operating conditions and the anticipated heating effect of the flame. (2) Protective systems designed to resist or contain explosions must be capable of withstanding the shock wave produced without losing system integrity. (3) Accessories connected to protective systems must be capable of withstanding the expected maximum explosion pressure without losing their capacity to function. (4) The reactions caused by pressure in peripheral equipment and connected pipe-work must be taken into consideration in the planning and design of protective systems.