What Is Water Hammer?
If you have metal pipes installed in your home, you probably will be familiar with the loud bang that happens in the pipe when a tap is shut off abruptly or a dishwasher or washing machine shuts off the water supply suddenly. The sound, that loud bang within your pipes is called water hammer or hydraulic shock (a technical term). Water hammer also happens when water changes directions or stops suddenly. This condition causes a sudden movement of pipes and causes them to bump into one another. Not only can this sound be annoying but also can damage the pipes, connections, joints, and fittings. If left for a long time, it can result in a pipe burst, water leaks, and costly plumbing repairs.
What are the Causes of Water Hammer?
Water hammer can be caused by the following factors:
Excessive pressure exceeding 80 psi in the water line
Water hammer can result from high water pressure at the main valve in the water line of a house.
Presence of debris or water in the air chambers
Except that the plumbing in your home is older, air chambers are installed these days. As a result, when there is debris or water in the air chambers of a plumbing system.
Use of a Home Appliance
Another cause of water hammer is the use of an appliance like a dishwasher or washing machine.
Failure to Securely Mount Pipes
When pipes are not fixed in place or mounted securely, they will be shaking freely when water passes through them.
Effects of Water Hammer
Irrespective of the degree of water hammer being experienced, it will cause water leaks, water damage or costly repairs later.
Contact: Emergency Plumber
How to Prevent Water Hammer
There are steps you can take to prevent water hammer from happening and increasing the risk of pipe bursting and expensive repairs. Here are some measures you can take to prevent water hammer from happening.
Installation of an Air Chamber
To prevent water hammer, you can install an air chamber, a short piece of upright pipe close to the valves producing the water hammer. The purpose of an air chamber is to create a piece of pipe filled only with air that water can move into to absorb the impact water hammer when it has to change direction suddenly. The plumber usually fabricates an air chamber onsite when installing the water pipes.
An air chamber comprises a fitting like letter “T” connecting to the main pipe. It is usually a dead-end type of pipe installed beside the key water pipe, and it is filled with air. When a water valve or faucet shuts off suddenly, there is a quick compression of the air in the air chamber to absorb the shock that could have gone into the pipes and caused loud banging.
To handle water hammer in any home, install an air chamber close to the washing machine that usually causes water hammer. However, the best thing is to fit air chambers to common sources of water hammer or other critical areas all-around a building.
Meanwhile, an air chamber may stop functioning correctly if it becomes filled with water, but it should be drained regularly to restore air into the chambers.
Follow the steps below to restore the air chamber:
- Turn off the main water pipe to the building
- Open the water faucet at the uppermost place in the building
- Open the lowest water faucets to drain water from every pipe (usually positioned in the basement or front yard)
- Air will flow back into the air chambers through the topmost faucet as the water drains out from lowest water faucet
- Turn off the water faucet in the basement as soon as water stops flowing, but turn on the main water valve to supply water to the building and ensure that the topmost faucet remains open until the water rises and flows out from its sprouts
- Now the entire plumbing system should be filled with water except the air chamber that should be full of air
Tightening Loose Pipes
When the plumbing pipes are not fastened or secured well, even a minor hydraulic shock will result in a noisy bang. If you are experiencing a case of unserious water hammer in your home, there is nothing much to worry about as it cannot result in pipe damage. However, it can be prevented by fastening any slack pipe strips of hangers securing the pipes to joists or studs. You can also wrap segments of foam pipe insulation around the pipes can help to stop banging.
Include more pipe hangers or straps at the points where pipes cross joists or studs. To cushion the pipes, you can also install pipe sleeves or put insulation around pipes running through bored holes. This solution may not be practical for pronounced water hammer; try another solution.
It is essential that you do not combine unrelated materials when using pipe hangers and metal straps to secure the metal pipes. Avoid using galvanized steel strips on copper pipe. One of the reasons is that electrolysis, a chemical reaction may happen between then and make the metal corrode. Use similar or compatible materials like using plastic or copper hangers or straps to secure copper pipes.
Installation of Water Pressure Regulator
In a situation that the entire pressure of water entering a house is excessively high, water hammer can happen. The average water pressure is from 30 to 55 psi; any pressure above this will result in water hammer. The high pressure of 100 psi and above will damage appliances.
Install a water pressure regulator at the point where the public pipe links the house’s main pipe to prevent and solve issues of water hammer.
Installation of Mechanical Water Shock Arrestors
Mechanical water shock arrestors contain an air bladder and a spring. The air bladder takes in water movement to reduce the impact of water hammer. These arrestors are a more sophisticated solution for handling water hammer in commercial buildings. They can be installed into the valves meant for the washing machine or sink faucets.