A device called an air chamber may be required instead of a mechanical water hammer suppressor. An air chamber is an extension of the water supply pipe near the pipe fitting that provides the air cushion to absorb hydraulic shock. Years ago, water hammer suppressors consisted of air chambers that were a vertically installed, air-filled piece of plugged pipe. The air offers the cushion to take that water hammer.
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. Years ago, water hammer suppressors were comprised of air chambers that were a vertically mounted, air-filled piece of plugged pipe. The air provides the cushion to absorb that water hammer.
Since air is water soluble, over time these air chambers would flood because all the air would be absorbed into the 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. Therefore, you cannot lock them in the wall. Each air chamber must have a means to recharge the air in the chamber. This means a valve on the top and a drain valve on the base.
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. This is simply because the air molecules in the air chamber, although normally separated from the water, mix with the water by dampening the pressure spike and, in a short time, the chamber becomes soaked and does almost nothing of what it was supposed to do. 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.