Fire in any one building is a rare event. But in a population of buildings in a country fires occur frequently and destroy life and property. In the United Kingdom, for example, public fire brigades attend more than 400,000 fires every year in which about 800 people are killed and 15,000 sustain non-fatal injuries. In addition, a number of fires occur which are not reported to the public fire brigades; some of these are dealt with by industrial fire brigades. Currently, fires in the UK cost more than £1,000 million per year in direct material damage to buildings and their contents. About 30 per cent of this total loss is in large fires, each costing £50,000 or more.