If you have metal plumbing pipes, it’s not unusual to hear them banging loudly when a faucet is turned off quickly or if a washing machine or dishwasher water intake is abruptly shut off. This banging noise is commonly referred to as water hammer, but the technically correct term is hydraulic shock. This happens when water has to change direction and/or stop quickly. Let’s take a closer look at water problems and four ways that you can fix them.
Why is a Water Hammer Issue a Problem?
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water hammer is very annoying; it creates a loud bang that can easily wake the entire house up at night. But, this is only the start of the problem, the banging sound that you hear in your pipes is actually a powerful hydraulic shockwave that is causing the plumbing pipes to move and crash against themselves. The pipes can even strike the supporting wooden framing members, and this can cause damage. A water hammer can easily loosen plumbing joints and/or break and crack your pipes.
This is primarily an issue with metal plumbing pipes, but it can still occur quietly in plastic water pipes and fixtures made from PEX and CPVC. These plastic pipes can still be damaged by powerful hydraulic forces, and this is easier to see compared to a metal pipe. Simply locate a section of exposed plastic pipe and watch it as someone quickly turns a faucet on and then off. You may notice that the plastic pipe flexes or moves as the water hammer moves through the pipe.
If you have water hammer problems in metal or plastic pipes, it’s a serious problem, and it needs to be fixed to avoid damage to your plumbing pipes and fixtures. Here are four common methods used by plumbers to get rid of water hammer problems.
- Secure All Loose Pipes
If the plumbing pipes in your home have not been secured well even a milder water hammer hydraulic shock will make a loud banging sound. A milder water hammer problem may not be severe enough to damage your pipes, and it could be prevented by securing the pipe straps.
The plumbing pipes could be secured to joists or studs, and foam pipe insulation can be wrapped around them to act as shock absorbers. This will cut down on the banging, and it’s easy to do in more exposed areas, such as the basement where access to the plumbing pipes is easier. Simply, tighten any loose plumbing straps and add some extra pipe hangers or straps where the pipes cross a joist or stud. If the plumbing pipes are run through a hole in a framing member, the pipe can be packed with a pipe sleeve or some insulation to fill the hole.
If the water hammer is more pronounced, this method will not provide adequate protection against potential damage and one of the other methods should be attempted. If you try this method, don’t mix dissimilar metals such as a copper pipe secured with a galvanized steel strap. This can create electrolysis, which is a chemical reaction that can corrode the metal surfaces. If you need to secure a copper pipe, use a copper or plastic hanger or pipe strap.
- A Water Pressure Regulator
A water hammer can be caused is the water pressure in the main water pipe is far too high for the home. A normal water pressure range is somewhere between 30-55 psi (pounds per square inch). When the water pressure is above 55 psi, it can easily create a water hammer problem, and a pressure above 100 psi can cause damage to your water using appliances.
If the water pressure is too high, it’s a good idea to consider installing a water pressure regulator to get the pressure under control. The water pressure regulator should be installed where the main water line enters the building. This device will protect fixtures and appliances, such as toilets, showers, water heaters, washing machines, and dishwashers, against high water pressure damage.
The water pressure in your home should be tested to verify that it’s outside the normal range. Once the water pressure regulator has been installed, you can adjust the water pressure to a more manageable level.
- Air Chambers
An air chamber is a short vertical segment of pipe installed near a valve that’s causing the water hammer problems. The pipe section is empty except for air, and this gives the water a cushion to rebound against as it changes direction suddenly or stops. This is a very simple method that can be applied to multiple problem areas in your home.
The air chamber is usually fabricated and installed by your plumber on site. Standard plumbing fittings and pipes are used to create the air chamber, or you could opt to buy a commercial product instead. In both cases, the air chamber will have a fitting to connect it to the main plumbing pipe, and a horizontal pipe that leads to a 6” capped vertical pipe. This is the air chamber; it’s a dead end away from the water supply that’s filled with an air pocket.
The main problem with an air chamber is that if it fills with water, it will not work correctly. This can be fixed by draining the water supply system, and this will restore the air to the chamber.
- Mechanical Water Shock Arrestors
If an air chamber is impractical, mechanical water shock arrestors can be used instead. These are a more sophisticated solution; the sealed units have an air bladder and springs inside to mitigate water hammer effects by absorbing movement. A mechanical water shock arrestor typically has a screw on or compression fitting for simple installation. These units don’t need to be recharged with air like an air chamber, but they do wear out over time, and then they need to be replaced. These are a popular choice for commercial buildings, and they are available in different sizes.
By Giovanni Longo President Flood Brothers Plumbing
Giovanni Longo is a 3rd generation master plumber who has been practicing his craft and trade in the greater Los Angeles area for well over a decade and a half. A plumbing and hydraulics-engineering innovator, Giovanni’s particular world-class expertise focuses on dealing with challenging sewer system designs as well as resolving complex commercial and residential draining issues. As a certified Flood Mitigation expert, he is also well versed in a wide variety of water damage and remediation solution.
