One of the most common sources of noise in industry is the noise generated from vibrating machinery. For example, a 5-hp motor rotating at 1800 rpm is rather quiet, but if it is bolted directly to a metal table, the noise level can rise easily to 90 dBA at a distance of 5 ft. In this instance, the metal tabletop [...]
A great deal of the unwanted noise in all buildings, from factories and workshops to administrative buildings and hospitals, is caused by machinery, plant and equipment. It is, therefore, of the utmost importance that all such equipment should be carefully selected with this in mind and installed in such a way that structure-borne noise is kept to the minimum and [...]
In addition to lead and lead-loaded products, there are many other materials used for sound attenuation and vibration control. We shall examine these other materials and some of their applications. Materials with high sound absorption qualities generally have soft porous surfaces. When sound waves come in contact with these absorptive surfaces, air travels in and out of the pores in [...]