Fire spread to upper floor is mostly incurred by external window flames, which depends on the generation rate of fuel volatiles from combustible products in the fire room. The generation rate of the volatiles is thought to be strongly influenced by the area of the combustible exposed to the fire environment. In order to assess the risk of fire spread to upper floor in high-rise buildings, it is important to know the surface area of combustibles contained in building spaces in actual use. Therefore, the fire loads and surface areas of the combustibles in office, hotel room, and apartment, which are considered to be dominant use of high-rise buildings, are investigated. The correlation between the fire load density and the surface area factor, of live fire load in actual use, was obtained for each of the occupancies.
