Measurements of the influence of fittings and roof pitch on the sound field in panel-roof factories

Abstract Measurements are presented of the sound absorption of two factory machines. Their third octave absorption, between 160 Hz and 5 kHz, is in the range 0.5–2.6 m 2 . Measurements of reverberation time (RT) and/or sound propagation (SP) in four factories with panel roofs, when empty and/or fitted, are also presented. The general characteristics of RT and SP in such factories, and the factors that influence them, are discussed in the light of the results. Fittings reduce the RT and large-distance SP levels in proportion to their volume density and to the absorption of the panel roof. Levels near a source can increase due to backscattering. Preferentially orientated fitting arrangements do not significantly affect the variation of SP with direction in a factory. The effect of roof pitch on factory SP is complicated. Large distance levels are generally lowest in the direction across the roof pitches.