Quantitative fire risk assessment for subdivided flats

Abstract

These years, there has been a concern about fire safety due to the occurrence of fire accidents in Hong Kong old buildings. The fire accidents raise concerns about other old tenement buildings in Hong Kong especially building with subdivided units (SDUs). Since most of the remodelling of subdivided flats are non-structural and therefore are exempt to apply for approval. The remodelled subdivided flats are not subject to supervision, and the basic safety requirements are often not up to standard. As a result, there may be a problem with fire safety and evacuation when a fire accident occurs in a subdivided flats building. In this paper, site inspections and numerical methods would be examined for the collection of firsthand information and to evaluate the risk level. To discover the fire safety issue of the subdivided flats building, characteristics of the common SDU would be identified through site inspections of different subdivided units in Hong Kong. The paper would also evaluate the risk level of existing subdivided units by applying quantity risk assessment: fault tree analysis and event tree analysis. Also, there is a comparison between the fire risk level of the subdivided unit buildings with standard modern buildings. Based on the collected research result, improvements and suggestions are investigated for reducing the fire risk level of SDU to an acceptable condition. The ultimate goal of the paper is to explore the issue of fire safety and the causes of fire accidents in the existing subdivided flats buildings in Hong Kong and to propose mitigation measures.