Understanding Water Hammer: Causes, Effects, and Prevention Tips

If you've ever heard a banging sound from your irrigation system, you likely have a water hammer issue. Water hammer refers to a loud banging or thumping noise that occurs due to uneven and unsteady water flow in your irrigation pipes. But what are the other causes of water hammer? How can you fix this problem? Let's find out all about water hammer in this guide.

What is Water Hammer

A water hammer is a phenomenon that may occur in any irrigation system where valves are used to control water flow. When you suddenly stop the water flow, such as abruptly turning the sprinkler system off, momentum carries the water rush into the closed valve. It creates a high-pressure shockwave, which produces a loud bang in your irrigation pipes.

Simply put, a water hammer is a pressure surge that occurs when running water is forced to suddenly change direction or stop. When water travels through pipes at high speed, and you suddenly close the valve to stop the water, all this force slams against a valve, producing a loud thumping sound. The sudden change in water flow causes loud noises and can potentially damage the pipes, sprinklers, and fittings.

In a sprinkler irrigation system, a water hammer can occur when a valve is closed too quickly or when the system's pressure changes suddenly.

Causes of Water Hammer

Many of us have heard pipes banging when a faucet is turned off. When there is a sudden change in water flow, shockwaves go through the system and rattle the pipe, reaching the valve with a loud noise. A water hammer is typically caused in high-pressure systems when a tap is turned off abruptly. There are various potential causes of water hammer, including:

Waterlogged Air Chambers

Pipes have built-in air chambers that act as cushions to absorb shockwaves produced by water that suddenly stops. These air chambers can become blocked with water or mineral debris. When they're waterlogged, there will be no cushion left to absorb the rising pressure in your system and prevent the shockwave from striking the pipe, which will result in bang noise and damage.

Loose Pipes

When pipes are not properly secured or have become completely unsecured, moving water and shockwaves can cause them to rattle, creating an echo of water hammer worse. Fix the pipes firmly to strong materials to keep them rigid for years.

Worn Stop Valves

Stop valves or control valves can also cause water hammers if their packing is loose or the washers are worn. These valves control the water flow into your irrigation system pipework, so they'll always be open during the water hammer. The shockwaves traveling through the pipe can rattle the valve handle and jumper.

Entrapped Air

Water hammer can occur due to trapped air inside the pipes. If empty pipes are filled too quickly, air can enter your system.

How to remove air from pipes and repair water hammer? Make sure pipes are filled slowly to reduce the chance of air buildup. In addition, you can install air-relief valves to release entrapped air. These valves are installed at higher points in the system. Another way to remove entrapped air is to increase the water velocity by letting water run for a while until it pushes the trapped air out.

Fast Acting Valves

Fast-acting valves such as solenoid valves are also common causes of a water hammer. These valves stop water instantly, due to which water shock waves reverberate through the pipe.

Common Effects of Water Hammer

Water hammer may seem harmless, but ignoring this issue can seriously damage your home water system. Some long-term effects of water hammer include:

• Leaks in pipes, fittings, and connections
• External property damage, such as corrosion of infrastructure and electrical equipment foundation damage
• Ruptured pipes due to high built-up pressure
• Costly repairs, installations, and maintenance of the system and property

Ways to Prevent and Fix Water Hammer

If you feel or hear water hammer on your home floor or irrigation pipes, acting quickly and fixing the problem is crucial to avoid damage. Here are some of the best ways to stop and deal with water hammer.

Install a Water Hammer Arrestor

Installing a water hammer arrestor is the most effective way to prevent water hammer in your system. These arrestors are a modern version of air chambers. A water hammer arrestor absorbs the pressure and shockwave produced by abrupt flow and pressure changes. They use a piston to compress air, which reduces shockwaves and absorbs water movement.

Hammer arrestors are easy to install and inexpensive, making them a good investment for protecting your system. Install this device near your valves or other risky areas to lower the risk of water hammer. Water arrestors also do not need any ongoing maintenance, so they are long-term solution water hammers.

Secure and Wrap Loose Pipes

If your water hammer results from loose pipe straps, tighten them all or replace them to secure pipes in place. Check all pipes to ensure they are firmly secured to their surroundings using sturdy fixings. However, carefully choose the strap material because some metals can react with one another and corrode. You can also wrap pipes in foam insulation to absorb the shock waves.

Install Pressure Regulators

This is another effective way to combat the water hammer issue. Pressure regulators maintain a consistent water flow in your home's pipes and prevent pressure buildup. If your system's water pressure fluctuates much, which is common in older homes, installing this device would be highly helpful.

Change Zone Order

If you have an automatic sprinkler system, you can prevent water hammering by changing how your irrigation zones run. Figure out which valve or zones use less water—the one with fewer sprinklers—and then rewire the controller. You can uniformly distribute the pressure throughout the system by changing sprinkler zones. With this method, each zone will run separately, which will allow the water pressure to adjust gradually in the zone instead of having multiple valves open or close at once.

Valve Care

Another important step to prevent water hammer is to ensure that all valves are opened and closed smoothly and slowly. Avoid opening and slamming valves shut too quickly, as this can lead to sudden pressure changes, which causes water hammer. Change the speed at which your control valves close. Slower closures reduce the chance of water hammer by allowing the water to stop gradually.

Irrigation System Care

Regular inspection and maintenance of your irrigation system can prevent water hammer from becoming a serious problem. Inspect your pipes, valves, and fittings for leaks or signs of damage, and ensure all components are working in good condition. If you frequently experience water hammer issues, it is best to consider a professional inspection.

The Bottom Line

A water hammer is a pressure surge in an irrigation system that must be fixed immediately to prevent damage to your system. This issue can look minor at first, but it can also cause damage to your system. If it is not controlled or fixed, it can cause leaks, damage pipes, and lead to costly repairs. Implement the above strategies to enjoy the efficiency of your irrigation system without the loud noise of the water hammer disturbing your peace.

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