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Water hammer correction (C) Carson Dunlop Associates Water Hammer Preventer Installation Guide

Water hammer control location, codes, manuals, sources
Cure banging water pipe noise

Water hammer arrester selection, installation, codes, guides:

This article series explains how to diagnose and fix banging pipes & water hammer noise in buildings and in plumbing systems.

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Water Hammer Arrestor Size & Location Specifications

Photograph of this antiquated laundry sink with several unsanitary plumbing violations in view.Article Contents

Water hammer noises in plumbing is also called hydrostatic shock. Here we explain where to install a device to control water hammer, stop hydrostatic shock, and stop the horrible banging pipe noises caused by that problem.

Here we provide copies of water hammer arrester installation manuals and guides, water hammer plumbing codes, and a list of manufacturers and sources of devices used to stop water hammer and hydrostatic shock noise and banging pipes.

Page top sketch of correcting water hammer noise (above) provided courtesy of Carson Dunlop Associates, a Toronto home inspection and education company.

Photo: an Oatey "Quiet Pipes" water hammer arrestor for sale at a Home Depot supply store.

[Click to enlarge any image]

Where do I install the water hammer arrestor?

Andy said:

I've recently replaced a booster pump in my residence. This new pump switches on Immediately on noting a pressure drop (water being used) versus the old one which had a timer delay before powering on.

I installed a Honeywell pressure reducer on the supply side of the pump and my total pressure is around 60.

All should be good - but when water is used, there is quite a hammer going on.

The hammer appears to be on the supply side of the pressure reducer/pump (because I hear a copper bang) versus on the output side of the pump (house flow which is plastic).

I thought about maybe installing an arrestor, but since the hammer is on the supply side, I have no idea where to install it. I also find it odd that I have a hammer on the supply side.

Any advice would be appreciated. The pump vendor is suggesting a pressure tank on the output side, but until I understand what is going on, I don't want to start modifying plumbing. Thanks. - 2 Nov 2015

Reply: install the water hammer arrestor close to the noisy valve or control or use a special model

Indeed I'd install a water hammer arrestor on the side of equipment, valve, or device where the hammering appears to occur; Anywhere close to that point should work.

Usually we install the water hammer arrestor between the shutoff valve and the incoming water supply line - close to the valve.

Or we may need to install a water hammer arrestor on both hot and cold water piping systems.

If that doesn't work for you I suspect the water hammer arrestor was not properly sized. Typically a smaller residential-type water hammer arrestor has 1-2 cubic inches in volume and can handle one to four plumbing fixtures. For example a Sioux-Chief 660-series water hammer arrestor contains 1.4 cubic inches.

A different model of water hammer arrestor (such as the Sioux-Chief 660-GTR-series arrestor) is designed for installation at water supply valves on hot or cold water piping systems - you should consider this option.

For severe water hammer problems or in commercial or larger installations with more fixtures or larger diameter water piping (and perhaps with faster water velocities) Sioux-Chief provides a series of higher capacity (larger) water hammer arrester devices in its 650-series water hammer arresters.

The 650-series water hammer arrester is sold in six sizes (A through F) and contains from 5 to 36 cubic inches of volume.

The smallest of the 650 series water hammer arrester contains 5 cubic inches in its pressurized air cushion and can support 1-11 plumbing fixtures while he largest water hammer arrester (Model 660-F at 36 cu. in.) can support from 155 to 330 plumbing fixture units.

Even larger volume, height and diameter water hammer arresters are available for special applications.

Here is what water hammer manufacturers say about water hammer arrestor size and location:

"The location should be at the piping serving the fixture(s) and normally between the last two fixtures. " - J.R. Smith Manufacturing Co. (Op. cit.)

"Water hammer arresters shall be specifically sized and have sufficient volume of air to dissipate the calculated kinetic energy generated by closing residential or commercial faucets or valves. Arresters shall be installed on both hot and cold lines on the supply stops where applicable.

Arresters shall be approved for installation with no access panel required. Water hammer arresters shall be ANSI/ASSE 1010 2004 certified. " - Sioux Chief Manufacturing Co. (Op. cit.)

Water Hammer Arrestor Plumbing Codes, Installation Guides & Instruction Manuals

Where to Buy Water Hammer Arrestors - water hammer suppression products

Sioux Chief water hammer arrester - www.siouxchief.com sold world wide


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Reader Comments, Questions & Answers About The Article Above

Below you will find questions and answers previously posted on this page at its page bottom reader comment box.

Reader Q&A - also see RECOMMENDED ARTICLES & FAQs

On 2024-06-30 by Jan - home irrigation system is causing water hammer in the house

My home sprinkler irrigation system (60psi) is causing a water hammer inside the house only when any zone selected to run first starts (doesn't matter which one of 9zones). The master valve started alone doesn't hammer, only when the first zone starts and last zone ends (but not as loudly).

Zone lines go above or below the manifolds but manifolds are at about the same level in the system and master valve is about 2 ft higher. . System is 30+ years old and didn't hammer in previous years.

Short of replacing the entire system, I would like to try a water hammer arrestor, but not sure where to put it. If inside the house, can it be mounted horizontally. The jolt spot is where the three-quarter inch supply T's to various feeds.

If on the irrigation system outside, is it Supply side or downstream side of the master valve. Can the arrestor be mounted on a T with an elbow or downward if outside on the irrigation system.

On 2024-06-30 by InspectApedia Publisher

@Jan,

From the article above we have

Here is what water hammer manufacturers say about water hammer arrestor size and location:

"The location should be at the piping serving the fixture(s) and normally between the last two fixtures. " - J.R. Smith Manufacturing Co. (Op. cit.)

"Water hammer arresters shall be specifically sized and have sufficient volume of air to dissipate the calculated kinetic energy generated by closing residential or commercial faucets or valves.

We reviewed the installation instructions for water hammer arrestors provided with this article: all say that their water hammer arrestor can be mounted in any position, including horizontal.

First try putting a water hammer device on the inlet to the master valve (the supply side).

If that doesn't help I would try putting a water hammer arrestor at the inlet to both the first and last sprinkler zones.

If that doesn't work we might need a more costly correction:

I've seen this problem before as have a number of our readers, both on sprinkler irrigation systems and on heating zones; in most cases we were able to fix the issue by changing to a slow-opening or slow-closing control valve.

Keep me posted.

Daniel

On 2024-07-08 by Jan

@InspectApedia Publisher, I have been thinking about where the water hammer occurs and the fact that I don't feel it in the PVC pipe at all. My main is 1 inch coming out of the basement floor and continues to be 1 inch going to the irrigation system.

At the point where it tees from the main to the irrigation system is also where the pipe steps down to 3/4 inch and goes to supply the rest of the house.

What I think is happening, is when the irrigation system turns on the pressure in the house line drops until the irrigation line is charged at which point the pressure again increases in the house supply line and I get the hammer.

I don't know if that should be a pressure tank to stabilize the pressure in the house or if I should put the water hammer arrestor on the house line since that is where the hammer is occurring.

I do not feel a jolt in the PVC irrigation line, only in the household three-quarter inch copper line where it branches in a few different directions to feed the bathrooms (half inch) kitchen sink [ half inch) and hot water tank (three-quarter inch).

Does this sound reasonable, since the hammer occurs when the sprinkler system charges the first zone and not when it shuts off. Insights/Suggestions/Recommendations would be appreciated.

On 2024-07-08 by InspectApedia Publisher - plastic piping may have less water hammer due to flexibility

@Jan,

Interesting additional detail, and helpful.

There are a couple of things to consider

First I'm not surprised that there's less water hammer effect where plastic piping is involved, both because it's flexible and possibly because it's a smaller diameter line with less water volume.

Second it's important to understand that water hammer happens because of a combination of water velocity and the sudden shut off or cessation of flow.

So you should be observing this water hammer sound when valves are closing. That should be diagnostic.

So when you're linking the sound to pressure equalization I have a little trouble following that.

Finally, I need to understand your water system. Except for some demand type water pumps that don't use an external water pressure tank, practically all pump driven water systems do use a pressure tank. And we often do add a water pressure tank on municipal systems.

On 2024-07-08 by Jan

water hammer in home irrigation system layout (C) InspectApedia.com Jan@InspectApedia Publisher attached is a diagram of how the main supply line comes into the house makes a tea about 4 feet off the floor with 1 inch copper going up another 4 feed and going through the outside wall to the PVC and master valve.

The other part of the tea steps down to a three-quarter inch line which goes up about 4 feet and first to the three-quarter inch line feeding the rest of the house and a half inch to a hose bib.

The irrigation line goes to a master valve about a foot outside the house and the first manifold is about 2 feet from the master valve. The mainline continues to two other manifolds as a 1 inch mainline.

Each of the manifolds connect to three Ridell three-quarter inch zone valves, the yard is large and the nine zones are fairly long on three-quarter inch line with what I call ratchet heads on most of them and one zone that is just pop-ups. Three zones go up/downhill.

The three-quarter inch copper line that continues in the house runs along the floor Joyce about 5 feet and then makes two 90° turns to zigzag through the joist and three-quarter inch line continues about another 10 feet to where it tees three-quarter inch to the hot water tank and half inch in numerous connecting tees to the sinks bathrooms and washing machine.

I call with the birds nest where Most of the half inch lines all branch at the three-quarter inch line to disperse throughout the house. the three-quarter inch Continues to the water heater at that location also.

When the irrigation program starts , there is an immediate waterhammer when the first zone starts. If I run a manual program, not starting with zone one, whatever zone I start first does the same thing, it create a hammer. It doesn't matter if the master valve is opened first in the manual cycle or after I have set the zones and then open the master.

The hammer is heard in the three-quarter inch copper line inside the house all along from the zigzag, to the birds nest.

When the irrigation program shuts off at the very end of the program (not after each valve), there is a sound of the system shutting off with a slight noise in the inside house pipes but not The boom like the hammer that wakes me up at 1 AM when the irrigation program starts, just more of a clunk like when I shut off the kitchen sink valve.

Hope this diagram helps you help me and I thank you for your persistence.

On 2024-07-12 by Jan

Update: got a washing machine water hammer arrestor that I rigged up on the half inch hose bib which is about as close as I can get to the 3/4" line without cutting pipes to test effects. It cut the water hammer noise down by about 2/3 and minimal shaking so I will investigate putting a water hammer arrestor of appropriate size on 3/4" line as close as I can get to the irrigation line.

On 2024-07-12 by InspectApedia Publisher

@Jan,

That's helpful feedback.

FWIW the usual advice from the water hammer arrester manufacturers is (eg Watts) you should install the device as close as possible to the source of the "shock" that's producing that slam-bang noise.

Usually that's a control valve.

So where are the valves that open and shut to control your irrigation system? Put the arrester there.

On 2022-08-13 by David

If using Overnore plumbing why do you have to put a hammer on your icemaker

On 2022-08-13 by InspectApedia-911 (mod)

@David,

if you are reading in a manufacturer's instructions the requirement for a water hammer arresting device on an ice maker I can but guess that the manufacturer has found that in some installations the water feed for the ice maker is controlled by a valve that causes water hammer problems.

On 2022-07-08 by Jim - can I install the water arrestor system upside down?

I have a what it's two water hammer in wall system to install. I have pipes feeding down from attic can I install the system upside down ?

On 2022-08-13 by InspectApedia-911 (mod)

@Jim,

A review of the water hammer instructions included as PDF files in the article above show us that most of these devices can be installed in any position.

Water hammer arresters work in any position because they are constructed with an internal diaphragm or seal that keeps an air or gas charge separate from the water.

On 2021-03-22 by Nicc44@comcast.net

What year were Water Hammer Arrestors mandatory for new homes?

On 2021-03-22 by danjoefriedman (mod)

@Nicc44@comcast.net,

Water hammer arrestors have not ever been mandatory.

On 2020-01-01 by KP - can I adjust arrestors to get rid of banging?

I installed water hammer arrestors on my washing machine. They worked great for a couple years...we just recently noticed low water pressure and changed our whole house water filter, which worked on the water pressure. But now the pipes are banging again. Do I adjust the arrestors somehow?

On 2020-01-02 by danjoefriedman (mod)

It's just an uninformed guess but it's possible that debris has entered in clogged the water hammer arrestors and they need to be replaced

On 2022-05-21 by bob

@KP, you figure it out?

On 2022-05-21 by InspectApedia-911 (mod)

@bob,

We didn't hear an update from KP, but it would have made sense to replace the water hammer arrestors as the first step.

The result would be diagnostic.

Generally water hammer is a velocity problem although occasionally similar noises are produced by a short cycling water pump.


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Citations & References

In addition to any citations in the article above, a full list is available on request.

  • ANSI Standard S12.60 – 2002, “Acoustical Performance Criteria, Design Requirements, and Guidelines for Schools.”
  • ASHRAE, . 2007 ASHRAE Handbook – HVAC Applications, p. 47.34, Table 44, Plumbing Noise Levels
  • ASPE, "Acoustics in Plumbing Systems", [PDF] American Society of Plumbing Engineers, Continuing Education, (October 2012), retrieved 11/2/2015, original source: https://www.aspe.org/sites/default/files/webfm/ContinuingEd/PSD_CEU_192Oct12.pdf
  • Blacoh™ Fluid Control, Website: http://www.blacoh.com, Tel: 951-239-3930, BLACOH Fluid Control, Inc. 601 Columbia Ave, Bldg D Riverside, CA 92507 USA Phone: 888.494.3179 951.239.3930 Fax: 951.342.3101 Email: sales@blacoh.com Blacoh sells Sentry pulsation dampeners and surge suppressors that (quoting):
    ... remove virtually all hydraulic shock, enhancing all-around performance and reliability of fluid flow in industrial and chemical transfer applications.
  • California Building Code, 2001 California Building Code, Appendix Ch. 12, Section 1208, Sound Transmission Control.
  • Douststop Anti Hammer Water Control Valve, Doust, Australia, also available online from http://www.bunnings.com.au/
  • Duan, Huan-Feng. "Discussion of “Analysis of PVC Pipe-Wall Viscoelasticity during Water Hammer” by AK Soares, DIC Covas, and LFR Reis." Journal of Hydraulic Engineering 136, no. 8 (2010): 547-548.
  • Brian Boman, "Chapter 21, Hydraulics", University of Florida, Indian River Research & Eductation Facility, 2199 South Rock Road, Fort Pierce, Florida 34945-3138 Tel: (772) 468-3922, Email: bjbo@ufl.edu, retrieved 3/3/2014, original source: http://irrec.ifas.ufl.edu/citrusbmp/ Water%20and%20FL%20Citrus/21%20Chap21.pdf
  • J.R. Smith Manufacturing, 2781 Gunter Park Dr. E. Montgomery, AL 36109-1405, USA, Tel: (800) 467-6484, Email: info@jrsmith.com, Website: http://www.jrsmith.com/
  • Kwolkoski, Jeffrey P., P.E., "An effective new approach to isolate plumbing stub-outs in residential construction", [PDF] Inter-Noise 2006, December 2006, retrieved 11/2/2015, original source: http://waveengineering.co/wp-content/uploads/2012/06/Effective-new-approach-isolate-plumbing-stub-outs-in-residential_in06_755.pdf
    Abstract:

    Noise from plumbing systems is often an annoyance in multi-family and private residences. Isolating the plumbing from the wall studs and building structure is a common method of noise mitigation.

    A new approach to isolate plumbing for a shower was installed and the results were measured in the field. The same method and product may be effectively used for plumbing to toilets, sink, and at other “stub-out” locations.

    This paper summarizes the noise reduction achieved and compares the performance with other common methods and products.
  • Oatey Plumbing, website: http://www.oatey.com/ Oatey U.S., 4700 W.160th Street Cleveland, Ohio 44135, PH: (800) 321-9532, and Oatey Canada: 218 Wilkinson Road Unit 3, Brampton, Ontario Canada L6P 4M4, PH: (800) 321-9532 email: customerservice@oateyscs.com
  • Oatey Plumbing, Website: http://www.oatey.com/ Oatey U.S., 4700 W.160th Street Cleveland, Ohio 44135, USA, PH: (800) 321-9532, and Oatey Canada: 218 Wilkinson Road Unit 3, Brampton, Ontario Canada L6P 4M4, PH: (800) 321-9532 email: customerservice@oateyscs.com
  • Reece Plumbing Centres, "Understanding Water Hammer", Reece Plumbing Centres, Email: outlet@reece.com.au Website: reece.com.au, Outlet (Customer Update Publication), August 2004, retrieved 11/2/2015, original source http://www.reece.com.au/assets/Uploads/2004Aug.pdf
  • Silverstorm Water Hammer Arrestor, Australia, also available online from http://www.bunnings.com.au/
  • Sioux Chief Water Hammer Arresters (shown at left), Website: http://www.siouxchief.com,Sioux Chief, 24110 South Peculiar Drive Peculiar, MO 64078 USA, Phone 816-779-6104 800-821-3944, sold in Australia via https://www.masters.com.au Example: Sioux Chief 660-HB 3/4" water hammer hose arrestor, or Sioux Chief 660-TCO 1/4" water hammer arrestor tee for ice makers
  • Watts, 815 Chestnut Street, North Andover, MA, USA 01845-6098, web search 09/18/2010 original source: http://www.watts.com/pages/learnAbout/reducingValves.asp?catId=64
  • Watts Water Hammer Arrestors (Watt Series 05) or Watts Water Pressure Regulator (Watts Series 1156 or 25AUB) can correct water hammer water hammer-related leaks such as may occur at

    a BACKFLOW PREVENTER valve or temperture/pressure relief valve - Watts Water Products, 815 Chestnut Street, North Andover, MA, USA 01845-6098
  • Wetherill, Ewart A., "What dreadful noise of water in mine ears!* - Plumbing Noise - a Phenomenon of Urban Living", Sound and VIbration, June 2008, p. 12-16, Ewart A. Wetherill, Alameda CA, Website: www.SandV.com, Author's email: redwetherill@sbcglobal.net
  • In addition to citations & references found in this article, see the research citations given at the end of the related articles found at our suggested

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