Metal and membranous materials are often used for roofing of such large buildings as sport stadiums and exhibition halls. In such cases, noise radiated from roofs excited by rainfall often causes serious acoustic problems. In order to investigate the sound radiation characteristics of such kinds of roof construction, an artificial rainfall equipment was firstly constructed to simulate natural rainfall condition, and the sound radiation characteristics of various kinds of lightweight roof have been investigated by sound power measurement. In this paper (part 1), the way of simulating natural rainfall and the charcteristics of the artificial rainfall equipment are described.
