Post Earthquake Fire in Tall Buildings and the New Zealand Building Code
Degree GrantorUniversity of Canterbury
This report examines the factors involved in determining the fire safety in tall buildings following an earthquake, and assesses the risk to occupants in such an event for a building designed to the Acceptable Solutions of the New Zealand Building Code. The development of performance based design requirements for fire is reviewed, with particular reference to the New Zealand Building Code. The usual philosophy of such building codes is that they should consider all potential events that could lead to an unsatisfactory level of risk. The Acceptable Solutions of the New Zealand Code provide non-mandatory prescriptive design options for compliance. The section on fire safety does not specifically consider the impact of post- earthquake fire in the determining fire safety provisions. Of particular concern is the high probability of failure of active and passive fire safety systems observed in earthquake events throughout the world. The Acceptable Solution is also widely used as a base document for setting the safety level for alternative designs. Unfortunately it contains many provisions that lack the consistency, transparency and technical validation to give practitioners confidence that its use will guarantee satisfactory performance. In this report, a case study building designed to the Acceptable Solution is assessed for life safety following an earthquake, and the probability of loss of life in event of a fire is found to be significant. Failures of the sprinkler system and the passive protection to the stairs are identified as the principal contributors to the unsatisfactory performance, and recommendations are made for improving their reliability.