06 - Fire Following Earthquake
Damage to infrastructure after an earthquake is a major loss trigger. One of the consequences of such damage is fire following a seismic event.
This can be caused not only by damage to piping and tanks but also impairment of fire fighting system, eg. damage to water supply system (piping, tanks) and/or pumps as well as fire walls.
In other words, an earthquake can not only trigger a fire by releasing combustible material but also impair passive or active fire fighting systems.
- Insufficient or missing gaps between the piping and wall at penetrations. This can cause shearing of the pipe and release of contents during an earthquake.
- Improper bracing of piping. Critical piping must be braced against swaying to prevent impact against each other pipes, structural elements, etc. Bracing should be done with tensioned wired or rigid elements.
- Inadequate design of fire fighting pump room. Unanchored pumps, suspended ceilings, inadequate gaps at pipe wall penetrations, lack of anchorage of day tank are some of the common issues identified in fire fighting pump houses, which are susceptible to damage during seismic shaking.
- Poor anchorage of tanks and equipment piping. Tall equipment or liquid containers are especially susceptible to damage if not properly anchored. Piping connected to such equipment, if not provided with flexible joints and suitable bracing, are also susceptible to damage.
- Critical piping to be braced from swaying by means of supporting frames, tensioned wires, etc. Attention is to be given to the connection of the bracing to the pipes. Refer to Federal Emergency Agency document FEMA P-414 for best practice guidance.
- Provide an adequate gap around critical piping at penetrations of walls. Gaps are to be filled with suitable non-combustible fire stopping material that can deform under seismic loading, eg. acrylic sealants.
- All production critical equipment, including fire-fighting pumps, to be properly anchored to the foundations. Anchor bolt configuration and foundation design are to be checked by qualified structural engineer.
- Avoid connection of critical piping, including fire fighting water, valves and equipment to unreinforced masonry or concrete block walls. Such components are to be supported by engineered frames anchored to the concrete floor slab and load-bearing elements (columns, beams, etc.). Since these components may alter the seismic performance of the load-bearing elements a qualified structural engineer should control the adequacy of the elements.
- Use seismic gas shut-off valves with caution. These should be designed for the pressures, temperatures, pipe diameters, etc. prevalent at the facility in which they are to be installed. Impact of sudden gas shut-off on operation of facility, handling of gas already inside the facility, etc. are just some of the issues that should be considered during valve selection. Installation and maintenance can only be performed by qualified technicians. In some countries, the components must be approved by regulatory authorities.
- Flexible connections should be provided at connection of piping to equipment, seismic joints and other critical locations.