Noise attenuation in factories

The cost of reducing noise levels in factories by covering large surfaces with sound absorbents is high. It is therefore important to be able to calculate in advance the effectiveness of absorbents and to determine how absorbents may be chosen and distributed for maximal noise reduction for the invested capital. For this purpose a mathematical model of sound propagation and attenuation in factories has been developed on certain simplifying assumptions. The interrelationship between the different parameters is found to be rather intricate and the mathematical model must be evaluated using a computer program. The influence on the noise levels of sound scattering objects, the shape and size of the factory and absorbents on the room surfaces have been studied. Especially if the ceiling is high, acoustic baffles are found to be more efficient than absorbents on the ceiling in reducing noise levels.