How long should a pipe be added and installed on the top of a riser of the highest fixture level to absorb air pressure and reduce excessive hammering sound?

The appropriate length of the pipe added and installed at the top of a riser, specifically for the purpose of absorbing air pressure and reducing excessive hammering sound, is crucial for effective plumbing design. Typically, lengths in the range of 0.3 to 0.9 meters are recommended. This range is considered optimal because it allows for sufficient space to accommodate air pressure fluctuations and dampen the sound created by water hammer without causing excessive dead space or air pockets that could lead to other plumbing issues.

The main function of this pipe, often referred to as an air chamber or a shock absorber, is to provide a cushion of air that can compress when water flow changes rapidly. Thus, a length of 0.3 to 0.9 meters is effective in providing adequate air volume for this purpose, promoting better performance in managing hydraulic shock.

Lengths outside of this range, whether too short or too long, may not provide the desired effect. If the pipe is too short, it might not hold enough air to effectively dampen pressure spikes. Conversely, a significantly longer pipe could complicate the plumbing arrangement without adding much benefit, potentially leading to other complications in drainage or air flow.