When it comes to plumbing systems, water hammer can be a major issue. It occurs when water is suddenly stopped or changed in direction, resulting in a pressure spike that can cause damage to pipes and fixtures. To prevent this, many plumbers use a device called a water hammer arrestor. But what about an air chamber? Is it the same thing?An air chamber is an extension of the water supply pipe near the pipe fitting that provides an air cushion to absorb hydraulic shock.
Years ago, water hammer suppressors were comprised of air chambers that were a vertically mounted, air-filled piece of plugged pipe. The air provided the cushion to absorb the water hammer. However, because air is water soluble, over time these air chambers would eventually flood, since all the air would be absorbed by water. Once flooded, the bladder is no longer an air chamber, but a water chamber and will no longer absorb the pressure of the water hammer. The Uniform Plumbing Code took a slightly different approach. It was left out of the way for the use of an inner tube; however, it is not the standard 1 inch by 12 inch air chamber that many in the profession are used to.
The code was revised to require that all air chambers be accessible and have a means to recharge the air in the chamber. Air chambers are small lengths of pipe that are mounted in water pipes, close to a fitting. They are made to stop hydraulic shock, also known as water hammer. The air in the chamber compresses and absorbs the impact of water that moves sharply in the pipes. All of this happens when a device shuts off the water quickly. A water hammer suppressor is an air-filled chamber designed to cushion the convulsive effects of water hammer in a plumbing system.
This requires that there are two distinct and separate pressure systems in a total system, air and water. There are two main types of water hammer suppressors, those equipped with pistons and those that are not equipped with pistons. Among the various means for damping the pressure peak of water hammer, varieties equipped with a piston are the most effective. Although there are many methods to stop water hammer, a simple air chamber for absorbing the pressure increase caused by water hammer has been found to be ineffective. It is a fortunate fact that this type of arresting device has become obsolete. A water hammer suppressor works much like an old-style bladder, but includes a chamber filled with air or gas that is sealed by a diaphragm or piston. So while an air chamber may have been used in years past as a way to stop hydraulic shock or water hammer, it is no longer effective and has been replaced by more modern devices such as water hammer arrestors.
