Passive fire protection (PFP) systems that are damaged by earthquakes may suffer significant reductions in fire resistance, resulting in increased risks to life safety in the event of an outbreak of post-earthquake fire and subsequent spread. In the aftermath of the Canterbury (New Zealand) earthquake events, damage to PFP systems has been surveyed in moderately damaged buildings. The degree of damage observed ranged from minimal, to moderate damage where some fire resistance remains, to extensively damaged where no protection remains. This paper focuses on damage in the moderate range where the majority of PFP systems protecting a fire compartment were largely intact, but one or two systems such as a doorset or a firewall were showing some degree of damage that compromises the protection of the whole fire compartment. Following the building surveys, selected elements of damage to PFP systems were built into the fire resistance test specimens as defects and instrumented with thermocouples to assess the failure mechanisms. The reduction in fire resistance of the damaged systems was correlated to the degree of damage such as size of gaps, furnace pressure and oxygen content of the fire gases and then compared with fluid flow theory in restrictive openings. Traditionally, the focus has been on the risk of fires immediately following an earthquake event when the occupants are evacuating, and damaged PFP coupled with inoperable sprinklers due to loss of water supply and impeded egress routes are likely to impact life safety. It is now also acknowledged that PFP may be damaged in an otherwise structurally safe building that may be reoccupied postearthquake; this research also provides a basis for building assessors to require that damaged PFP be restored to specification.
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