Final answer:
Air-filled tubes in plumbing, known as water hammer arrestors, prevent water hammer by absorbing the shock caused by the sudden closure of faucets or valves, which protects the pipes and extends the lifespan of plumbing systems.
Step-by-step explanation:
When air-filled tubes or air chambers are installed in plumbing, they are usually used in combination with a gravity tank or a pressure tank. These air-filled tubes are necessary to prevent water hammer, which is a loud knocking noise that can occur when a faucet or valve is closed suddenly.
The air within the tubes acts as a cushion, absorbing the shock and thereby minimizing the pressure surge that causes water hammer. How they work is quite simple. When the water is turned off quickly, the momentum of the water flowing through the pipes suddenly stops, creating a shock wave that travels back through the piping system.
The air-filled tubes, strategically placed near water faucets, compress when this shock wave hits, reducing the force of the water and the resulting noise. This not only helps to protect the pipes from damage but also reduces the chances of leaks and extends the life of the plumbing fixtures. These systems are part of what's known as water hammer arrestors.