Sound isolated piping

The example of sound attenuation from water pipes and the consequent reduction in sound reflection off the walls shows the extent to which rubber can reduce the volume of sound. The situation is reproduced schematically in Figure 1 . An open tap causes a loud noise. The sound of the following water is conducted by the piping and then by wall brackets to the wall, from where it emanates into a neighbouring room. If the pipe is isolated from the brackets by rubber bands, the sound volume is considerably diminished, as Table 1 shows. This depends on the force exerted in the tightening of the rubber strip. The measurements show that rubber is more effective than cork. Light to average tightening of the bracket clip screws give an optimum noise reduction.

Figure 1 Sound-deadened water pipes

No.	Sound proofing material	Tightening of isolating material	Sound volume (phon)	Improvement with insulating material (phon)
1	without	-	55.5	0
2	rubber	light	39	16.5
3	rubber	average	39	16.5
4	rubber	strong	42	13.5
5	cork	light	42.5	13
6	cork	average	46	9.5
7	cork	strong	48.5	7

Table 1. Reduction of sound volume with rubber and cork in water pipe