Safety cost optimization of building projects in Hong Kong

A survey was undertaken of the losses or costs incurred in building contracts because of accidents on building sites. Altogether, 576 accidents from 18 building sites were investigated. On each site, an accident occurrence index (AOI) was calculated by dividing the total equivalent day loss by the total man-days required for the project. Using the results of the 18 projects, a relationship was obtained between the site accident costs and the AOI. Similarly, a relationship was found between the safety investment and the AOI. From these two curves, the optimal safety investment on a building site by a contractor could be determined. It was found that the minimum safety investment on a building project is about 0.6% of the contract sum. The above finding was based on accidents in which employees sustain fatal injuries or are absent from work for more than 3 consecutive days through injury. If first-aid-only and non-injury accidents were also considered, the minimum safety investment increased to 0.8% of the contract sum.