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Water Hammer

The leaky pipes discussion made me think about a current pipe issue I am having in our current house. It is known as Water Hammer. Water Hammer, as I know it, is when there is a sudden change in pressure in the pipes, eg, the toilet filling up and then stopping all of a sudden. This change causes a back pressure through the pipes which leads to a banging noise at the end. Water Hammer can eventually lead to damage to the pipes and the infrastructure that holds the pipes. One solution I have read about is shutting off the water main, then opening the faucet which is at the lowest point of the house and letting all the water in your pipes drain. Then open all the other faucets in the house. This will de-pressurize the pipes, and is a temporary solution at best. A more permanent solution is Water Hammer arrestors, which help equalize the pressure. These are common in newer houses, but my house was built in the 50's so I doubt it has these. Have you had any experience with plumbing and Water Hammer, and if so, how did you resolve it?

Hammer Water

I am no plummer, but I do know of the issue you are talking about. One of the things we did to solve the problem was as you mentioned: open the pipe at a certain pressure level until the sound goes away. However, for a pipe to bang it must be movable. Wouldn't a solution be to pin the pipe or should I say harness it? The other option is to bring the pipe to a level below or above the main. It is of course easier said than done and the cost involved may warrant a little background noise acceptable.

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Well, therein lies the problem. The pipes must have been experiencing this pressure for some time to the point where the force has caused them to become loose. Now the outcome is that the back pressure is resulting in the banging noise. The weather has been so cold lately, that I didn't want to chance opening outside pipes yet, because the one in my backyard is at the lowest level of the house.

Hammer Water

Water hammer (or, more generally, fluid hammer) is a pressure surge or wave caused by the kinetic energy of a fluid in motion when it is forced to stop or change direction suddenly. Moving water in a pipe has kinetic energy proportional to the mass of the water in a given volume times the square of the velocity of the water
For this reason, most pipe sizing charts recommend keeping the flow velocity at or below 5 ft/s (1.5 m/s). If the pipe is suddenly closed at the outlet (downstream), the mass of water before the closure is still moving forward with some force, building up a high pressure and shock waves.
In domestic plumbing this is experienced as a loud bang resembling a hammering noise. Water hammer can cause pipelines to break or even explode if the pressure is high enough.
Retrieved from "https://en.wikipedia.org/wiki/Water_hammer"

So, the water hammer happened this way:
The water flow through the pipes with a certain speed and get out.
When you suddenly close the valve the pressure inside the pipes increase very much for a short period of the time, because of fluid inertia.

Like the car hitting a wall.

There is nothing to do it's a physical low, fluid hammer will happened every time you shut a valve, but you can reduce the "weight" of the hammer, for eliminate the noise.

Obs. The noise come from INSIDE the pipe not because they are moving .

So:
1.you have to find when the WH occour , and which is the devices (valve, washing machine, etc) causing it.
2.then you have to install a damper (shock absorber) to the pipe, or to reduce the diameter of the pipe (between the main pipe and devices).
3.could be that the valve is broken with the parts inside moving uncontrollably so you have to change it.

Hope to be useful.

Hammer Water

The water hammer is most prevalent, and noisiest, after the upstairs toilet is flushed, and the tank has filled up. It might be as simple as replacing a valve in the toilet tank (haven't looked into that possibility yet). However, you can still hear the 'hammer' sound when any faucet in the house is turned on then off. I don't even know enough about toilets to figure out which valve controls the shut off when the tank is full. I do know that a properly working toilet should not shut off suddenly, but should gradually slow down to a trickle and then shut off. Maybe that is where my problem is.

Water Hammer

Another alternative to a water hammer arrestor is an air chamber that you can add to the piping near the quick closing valve (washing machine, icemaker, toilet, etc).

An air chamber is simply a section of pipe that extends straight up ~12"-18" off the piping serving the fixture and is capped at the top. When the piping is re-pressurised, the chamber remains full of air and act as a shock absorber. However, over time the water will absorb the air and it may become useless, but it can be recharged simply by letting air back into the water piping (close the water main and open a faucet upstream of the air chamber for a short period of time).

Water Hammer

Thanks for the suggestion, Martin! Fortunately for us, we just bought a new house, so we'll be moving out of the house we are currently in where the water hammer is prevalent. However, it is still good to know how to best tackle these kinds of problems, especially when you have a house of your own.

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Interestingly enough I was just thinking if you tested your 'new' home for this Water Hammer problem by going around the home and opening and closing the pipes slowly to see what you get?