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Comparative Sound Testing of Covered PVC to Cast Iron Pipe


Noise from vertical PVC drainage piping located inside wall cavities can be annoying in multistory
hotels and apartments at every floor level from water discharging from the upper floors. Noise from
horizontal PVC drainage piping in the same multi-story buildings can also be annoying through the
ceilings in the floors below. The only sensible solution in the past has been to use cast iron
pipe, now there is an alternative.

As sound engineers know, it is very difficult to reliably test the soundproofing qualities of
piping, because a simple change in the construction assembly, attaching or securing the pipe can
change sound tests results. ProVent has produced a special designed test rig that can actually test
the differences in sound transmissions between cast iron vertical plumbing stacks and PVC vertical
plumbing stacks which has ProVent’s Whisper Quite Shell Pipe Covering.

The Shell pipe simply covers the bare PVC pipe like pipe insulation, only using two flexible spacer
rings that holds the Shell pipe with 1/8 “ open air space around the entire circumference of the
PVC pipe. The air space absorbs the water sound from the PVC pipe and stops it
in-between the Shell pipe. The difference in sound from cast iron stacks to the Shell pipe stacks
was 1.5 dB for a 3” stack and 2.1 dB for a 4” stack. This testing has created a quality sound
rating of below a “Barely Perceptible Change in Decibel Level at 3 dB.” Effectively, the difference
is inaudible.

All the above sound testing was done by Kolano & Saha Sound Engineers, (INCE Board Certified
Personnel) Their full report with sound numbers, photos of the testing and the test rig are

By: Ken Cornwall CEO

ProVent Systems, Inc.



Click on the links below for more information on our Whisper Quiet Shell Pipe