banging noise

Hi,

I could use some insight on a problem that has been making my life hell. I have lived in my current condo for roughly a year, and about 6 weeks ago, a very loud rattling, banging, hammering sound started to emerge from the
wall above the bathtub whenever any of my upper or lower neighbors use their sink, tub, shower faucets, wash their clothes or flush their toilets. I don't hear the noise when the water is running from my own sink, tub or shower faucets. However, I can now also hear the noise when my washing machine initially fills with water, or when my toilet finishes refilling (though in this case the rattle is relatively muted), or if I really abruptly jerk my tub
faucet on and off. This problem just developed out of the blue over a month ago. Hundreds of times a day a loud series of 2 or 3 banging noises when others use their bathrooms. The sound seems to be coming from the area where the bathtub faucet is located. Apparently no one else has this problem where i live. If it's relevant, I seldom use my tub or shower as I traditionally shower at the gym. The person who owned the place before me had renovations done 6 years ago and moved the pipe.
The building maintenance department thinks this 6 week old problem is because of the renovations done years ago.
They think a pipe has come loose and needs to be anchored properly. Because the contractor hired by the previous owner moved the pipe so that it runs down beside the bottom of the tub and then up to the adjacent shower stall, it would require pulling out tiles and perhaps even pulling out the tub to access the pipe. They say this would be my responsibility.

Any thoughts on what is causing this noise ? Do you think it is likely a loose pipe ? Before I go ahead with this messy and potentially costly exercise, I wanted to ask if the problem could be caused by anything else ? Could it be
as simple as a loose washer or loose part in the faucet ? Or might it have anything to do with a air trapped somewhere ? Or could it have something to do with too much water pressure somewhere ? Any other potential explanations ?
My fear is that I will pay a lot of money for a plumber to tear things apart to find out that the problem can't be fixed on my end.
Thanks a lot and sorry for the long post.

This sounds like a "water hammer" problem. Once water gets moving, it has a fair amount of momentum and doesn't stop on a dime if a faucet is suddenly closed -- typical of a toilet, icemaker, washing machine, or any other appliance with a rapid shutoff. There are usually gadgets called "hammer arrestors" installed at those appliances to absorb the shock as the water flow is stopped. These are just air chambers, which can become filled with water over time. Once they're waterlogged, they no longer can absorb the shock, and the shock has to be absorbed by the pipe itself. This causes the pipe to move and bang around if it's not secured to the building framing. (Some fancy versions are sealed and don't get waterlogged.)

You have two options to fix this: 1) make sure hammer arrestors are installed and working, and 2) make sure all the pipes are secured.

A quick fix for waterlogged hammer arrestors is to drain the entire plumbing system, allowing all the water to run out of the arrestors and refill with air. I would try this to see if the problem goes away. If it does, however, it will be back in -- oh -- about 6 years. I would think your building maintenance department would be happy to help you with this experiment.

Checking for secured pipes and fixing them if they aren't obviously requires access to the pipes. Is there access to the tub's plumbing from behind the tub? Usually that's in a closet and there's an access panel to get to the plumbing. If that's the case, start there to see if you can locate the banging pipe(s). Same for the shower -- there might be a way to get at the plumbing from behind the shower without ripping up tile. In any case, if there are pipes other than yours banging around, you won't be able to do much about them.

Now for the bad news. Pipes banging around freely like this could be damaged over time and cause leaking -- sometimes big-time leaking. At that point it's a race to call your plumber AND your lawyer.

Mikey said:

You have two options to fix this: 1) make sure hammer arrestors are installed and working, and 2) make sure all the pipes are secured.

Now for the bad news. Pipes banging around freely like this could be damaged over time and cause leaking -- sometimes big-time leaking. At that point it's a race to call your plumber AND your lawyer.

Click to expand...

Well...Not so fast with lawyer!
If your association and maintenance people are worth their salt
show them this (Sans lawyer suggestion!) and they'll take action.
Perhaps help them with the sheet rock repair when they finish up!

Thanks for your opinions. I have encountered great resistance as default response seems to be " we see renovations, renovations are the cause, it's your problem, not ours"

This may be a dim question but would just like to make sure I know what I am talking about when I follow up- if I approach them and request they drain the system, exactly what would that entail ? Would they have to shut off other people's water ? I think they would outright refuse that.
I forgot to mention this point before, but will add now if it is significant- in the time i have been here, they have had to shut off the water in our building for the entire day 5 times. The most recent shutdown was not long before my
problem started and it was due to an emergency leak in the hot water tank (or something to that effect). Could the most recent shutdown have contributed to the problem I am now dealing with ? As I mentioned, they say no one else is having this problem.

I really appreciate your input. Thanks again

Some notorious noise makers are toilet fill valves. These can make moaning sounds, but if a toilet flapper valve is leaking, the frequent quick on-off cycle of a fill valve can cause the same effect as a solenoid controlled valve (such as an ice-maker, washing machine, etc.). Fluidmaster toilet valves are fairly quick on/off valves and tend to be more prone to this than some other brands. As noted, inertia and quick on/off cycles can and do move pipes if they aren't managed properly. A simple air chamber will become waterlogged fairly quickly (could happen in months depending on the quantity of on/off cycles). A hammer arrestor has a sealed air chamber and should work fine until and if it fails (should be a very long time). They need to be installed close to any fast closing valve.



If the plumber used air chambers, the only way to restore air to them is to drain the pipes (and this will drain the air chamber as well). This involves both turning the water off, then opening valves all over the place so air can get into the system. This may not be a practical solution in a multi-person dwelling. Another reason hammer arrestors are better - they're a long-term solution.

Pipe banging is worse the higher the system pressure is. If this just started, it might be that if work on the system replaced a pressure assist pump for the facility is now creating higher pressure, or if the static pressure is too high (maybe the PRV failed), it would exacerbate the problem.

You might want to get a pressure gage. They cost about $10 at a big-box store, or many hardware stores. It comes so it screws onto a hose bib - if you have a washing machine setup, you could do it there; or, you can buy adapters to screw it onto places like a faucet if you remove the aerator. The adapters might cost more than the gage, though.

water hammer arresters

Maybe I'm missing something here, but if the arresters eventually fill with water and become ineffective, how would draining the plumbing help fix that? If you drain the plumbing, the arresters are filled with water and capped on one end. You couldn't drain the water out could you, without venting one end of the arrester? It seems like the surface tension of the water wouldn't allow it to drain out of the arrester. I'm talking about the arresters made by capping a length of copper and soldering into the water line by the valves.

Eric

A true hammer arrestor has a sealed air chamber. It can be either a bladder or a piston. What you are referring to is an air chamber, and they plain don't work long term. Usually, when you drain the water, they do drain, restoring the air in the chamber, but not always. If you have air chambers, draining the system is the only way to restore them, and it may not work. You have to open many of the valves since you don't know how things are run, to ensure you can get air where it needs to go. This is a very iffy proposition. That is why proper arrestors are the proper choice. If they fail, you can replace them, but in the interim, they work quite well and for a long time. An air chamber could become waterlogged within weeks if the on/off cycles and their size caused a lot of gas absorbtion.


The one on the left is for a washer.
The one in the center can be soldered onto a tee.
The one on the right can be used inline like for a lav supply or an icemaker line.

noise

Common plumbing noises, such as water hammer, occur when a faucet or valve turns off. Ongoing noises while water is being used almost always are caused by faucets or toilet fill valves in need of repair or replacement. pipes do not come loose, and even if they did, there has to be some outside development that would cause them to move. Just water flowing through them would not do it.

fozzy12 said:

You couldn't drain the water out could you, without venting one end of the arrester?

Click to expand...

Fill a Coke bottle with water and turn it upside down. That's essentially what we're doing when we drain the plumbing.