Guide to Sound Control in Building Supply & Drain Piping
SOUND CONTROL for PLUMBING - CONTENTS: How to control plumbing noises in buildings. Drain & toilet flush sound noise control design details. Principles of plumbing pipe & equipment sound transmission in buildings. How to make a building quiet: plumbing sound isolation strategies for building drain piping, water supply piping & hot water heating pipes.
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Building plumbing system noise control & sound isolation:
This article explains methods and materials used to control plumbing piping & plumbing fixture sound transmission in buildings: how to assure quiet plumbing fixtures, plumbing drains, supply piping, heating piping in buildings.
We explain the difference in noise levels from plastic versus cast iron drain piping, we illustrate the sequence of steps in sound insulation useful for isolating noises a plumbing pipe chase from occupied building spaces, we describe noise sources traced to water supply piping & heating system pipes, and we list other plumbing-related sources of building noise. In a series of photo-illustrations we discuss plumbing drain pipe chase insulation & fire safety.
This article series discusses noise and sound control in buildings, and includes excerpts or adaptations from Best Practices Guide to Residential Construction, by Steven Bliss, courtesy of Wiley & Sons.
The page top photo shows our client commenting on a mix of plastic (more noisy) and cast iron (more quiet) drain piping in a building basement where renovations and conversion to occupied space were planned.
Plumbing drain & pipe chase noise control photo 1 - pipe chase construction: at left you can see a horizontal plumbing chase running beneath a floor above.
In typical indoor construction the builder might simply install drywall over the chase framing structure to enclose the supply and drain piping.
The result will be significant noise transmission into the room below, particularly when plastic drain piping has been used, such as the black ABS drain shown in our photo - courtesy Galow Homes . [Click to enlarge].
Plumbing chase noise control photo 2 - insulate wall or ceiling penetrations: at left you will see the orange foam insulation that was sprayed to seal the plumbing drain piping where it penetrates an interior wall.
The foam product selected here was chosen for its fire resistance to comply with local building codes.
We divide plumbing drain and fixture noises into two groups:
Plumbing defect noises associated with plumbing system problems or defects whose identification and diagnosis is discussed at our complete list of various plumbing system noise
See PLUMBING NOISE CHECKLIST for just that - a list of plumbing noise sources
Normal (but annoying) plumbing system noises that will be corrected by noise transmission control or sound insulation are discussed here at SOUND CONTROL for PLUMBING where we describe controlling the transmission of plumbing noises in buildings and where we give methods for mimizing plumbing noises and sounds.
Normal plumbing drain sounds
Plumbing chase noise control photo 3 - complete plumbing pipe chase insulation: as you can see in our photo at left, we completed insulating the pipe chase with spray foam insulation during building wall and ceiling insulation installation.
While thermal insulation was not required between this room and the occupied space above - for heating or cooling purposes, the cost of including the spray foam insulation in this area was low when contracted as part of a building-wide insulation job.
Insulating here provided excellent sound insulation and also improved the thermal performance and temperature consistency in both this room and in the floor above.
As we stated at PLUMBING DRAIN NOISE DIAGNOSIS, Hearing the sound of running water in a building drain is not likely to indicate a
problem with the drain system itself.
In older buildings where cast iron and steel drain pipes were used, not much
sound normally is heard: even the sound
of running water, say when a shower is running or when a toilet was flushed.
But in a more modern structure that uses plastic or copper drain piping these
materials can transmit the sound of running water to the building interior.
Builders can reduce sound transmission from plumbing lines by enclosing them
in insulated chaseways.
We have also found cases in pipes in a building transmit sounds from one area
of the building to another. We've also found that electromagnetic fields generated
in a building, say by a bank of electric meters located in one area, can be
transmitted to other building areas through metal piping.
Plumbing Noise & Sound Transmission Sources & Control
One of the most common noise complaints in single-family
construction is the sound of water gushing through
PVC waste pipes.
The best solution, short of using cast
iron, is to box in the pipes and fill the cavity with fiberglass
insulation. Then enclose the cavity with one or two
layers of drywall.
Plumbing chase noise control photo 4: Our photo (left) shows a different building in which the plastic drain waste piping was routed through a basement that was being finished and to be used as offices. This drain was a subject of recurrent noise complaints in the building.
The leak stains at the ceiling needed to be investigated and the source corrected before this piping run was enclosed in a heavily insulated drywall pipe chase to minimize sound transmission from the upstairs plumbing fixtures into the lower level offices.
Noises from water supply piping & hot water heating piping
Water supply and heating pipes can also radiate noise
through the framing if there is rigid contact between pipes
and framing or finish materials. This can be a particular
problem when heating pipes expand and contract. To avoid
these problems, make sure pipe runs are not tight against
While special non hardening
acoustical sealants are often specified in commercial
work, any high-quality sealant that remains flexible can
be effective in blocking sound transmission. Butyl, silicone,
and urethane caulk can all be used.
sound leaks, use sealant around electrical boxes, plumbing
penetrations, and any other penetrations in the wall or
Other sources of noises associated with water or heating piping in buildings
Poorly secured water supply or heating piping where pipes run along below floors or ceilings can lead to clanking or other noises. As Carson Dunlop point out in their Home Reference Book,
As valves are opened and closed, vibration can be set up in the piping making it rattle.
Sometimes this can be corrected by pushing newspapers into the wall cavity to keep the pipes from contacting the walls or each other. Foam insulation can also help in some cases.
Where a pipe passes through the floor system or wood studs, it may rub on the wood and squeak as the pipe expands and contracts with heat.
Hot water supply and heating baseboard piping noises where pipes creak, click, and clank at floor or wall penetrations, especially during temperature changes such as heating system on-off cycling or hot water usage.
Hot or cold water supply piping running water noises may be amplified and transmitted through some building areas when water is running through pipes that are mounted in contact with framing or in contact with floor or wall partition materials.
If you are debugging piping noises in a building and have been unable to locate the source of a running water sound, turn off water at the building water main and listen again.
This step eliminates running toilets and open faucets in the building. Try using a mechanic's stethoscope on water supply piping where the water piping enters the building. On occasion we have found that a running water sound was due to a leak in buried water supply piping outside of the building itself. Sound was transmitted through the pipe itself into the building interior.
Leaving a clearance opening to accommodate pipe movement during temperature changes, and sealing all pipe penetrations (discussed above) can substantially reduce indoor supply or heating piping noise.
Water hammer (or hydrostatic shock) is a noisy pipe problem that occurs when valves are shut off quickly. Water hammer can damage pipe connections and result in leakage.
See WATER HAMMER NOISE DIAGNOSE & CURE for details.
Water Heater Noises:
see NOISES COMING FROM WATER HEATER for the diagnosis and cure of clanking or thumping noises that may be coming from your water heater or heating boiler.
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(Oct 24, 2014) firstname.lastname@example.org said:
After flushing toilet, there are approx. 6 consecutive noises sounding like swishing of air in line. Also grout in one floor area near toilet shows signs of possible discoloration, or dampness underneath.
(Aug 17, 2015) John Thompson said:
My residence is about 7-8 years old. I have odd noises which occur about 2 feet inside my home at the location where a whole house water filter is. The plumbing coming into the house is a 1" PVC line which flows through the water filter housing [the filter was removed, but the noises remain]. The PVC pipe then goes immediately to a pressure reducing valve and then turns into a 3/4" copper line, to distribute water throughout the residence. I have a Hot Water Circulating Pump[now unplugged, but the noise was there before it was unplugged] and a 8" diameter Water Hammer Arrestor above my Hot Water heater. The noises occur at the Water Filter Housing and before the Pressure Reducing Valve. A noise almost always occurs when the water in the house is turned off at any location. It also occurs continuously when a faucet outside the home is turned off at the nozzel, but the water remains on. Sometime the noise sounds like a giant drip or some sort of moaning or humming noise. This has been going on for around a year, but not before. What can you tell me about trying to find the source of the noise and how to eliminate the noise? Thanks, John
John, I'd use a mechanic's sthetoscope and some digging to find the problem point: I suspect you'll need to change a valve or elbow or fitting that is vibrating as water flows through it.
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