The analysis and design of equipment and piping for fire and explosion loading is covered in FABIG Technical Note 8. Though the title of the Technical Note refers only to piping systems, it actually covers equipment in general as piping systems and the equipment to which they are connected are inevitably linked.
Industry experience has shown that it is neither practical nor necessary to design all pipes to withstand explosion and/or fire effects and current practice employs a criticality approach to determine which lines should be provided with explosion or fire resistance. There also are practical limits to the general level of explosion resistance that can be achieved with process piping. It is consequently necessary to take measures in the overall plant design and local layout to reduce probable explosion pressures. Best practice aims to reduce hazard and consequence by implementing the principles of inherently safe design. For onshore plants a major goal is to prevent the spread of explosion effects from one plot/unit to adjacent plot/units and to people beyond the plant boundary (Land-use planning aspects).
Pipes respond to explosion wind (drag pressure) rather than directly applied field pressure. Resistance to explosion wind demands that pipes be strong, that supports be located at close spacing along the pipe and that the structures on which they are mounted have adequate strength. Direct shock loading on pipes is small compared to explosion wind. This is mainly due to the speed with which shock fronts can pass piping systems, allowing rapid equalisation of upstream and downstream pressures.
Pressure and shock loads can however cause significant movement (and occasionally collapse) of deck structures, walls and large equipment items. If pipes interconnect these items, such that the pipes themselves become strained between adjacent supports, then it becomes essential for them to have the necessary ductile deformation capacity. However, design for ductile deformation capacity can conflict with the requirement for strength to resist explosion wind.
Detailed guidance on implementation of current best practice can be found in the Technical Note. Equal priority and equivalent guidance is given to design for fire, and assessment and design of process equipment and piping for such events, which often follow from explosions.