Water Hammer FAQ
Tuesday, March 4th, 2014
Chances are that you have heard the term ‘water hammer’ being used in relation to all sorts of loud and unusual banging noises associated with piping. However, in a great many cases the term is being bandied about incorrectly. Water hammer does not refer to the actual banging noise, but rather, one very specific problematic piping process which can generate a banging noise.
Where Does Water Hammer Come From?
Occasionally referred to as ‘fluid hammer’, water hammer occurs when water passes through a pipe quickly before being stopped abruptly (eg: when it encounters a blockage or someone closes the valve at the end of the pipe suddenly). The quick flowing water being forced into such a sudden stop is what water hammer is and is responsible for creating the noticeable banging noise. The force generated by the rapidly moving water’s momentum, in turn, causes it to condense somewhat and then bounce back in the opposite direction before stopping entirely.
Does Water Hammer Damage Pipes?
While the most immediately noticeable and annoying symptom of water hammer is the loud banging noise, it is probably the least serious aspect of the phenomenon. Given time, water hammer can cause serious damage to pipes, contributing to erosion and all the problems associated with that and, in some extreme cases, result in burst pipes.
Are Newer Pipes Affected by Water Hammer?
Fortunately, most modern domestic pipes are installed complete with what is known as ‘air cushions’. These are specially designed chambers which contain pockets of air which help ease the damage caused by water hammer. Although very helpful, such ‘air cushions’ are not an entirely perfect solution. Over time, the air chambers can become waterlogged, reducing their ability to negate the effects of water hammer. This is why water hammer sometimes begins to occur (seemingly) mysteriously in pipes which had previously exhibited no water hammer symptoms.
It is always worth consulting with your plumber in order to find out if your piping is fitted with such water hammer resistant measures.
How Can I Prevent Water Hammer?
In some cases, it will be possible for you to deal with small amounts of water hammer yourself. Taking heed of the following steps can help you limit the damaging effects of water hammer:
- Switch off the source of water behind the waterlogged section of piping.
- Find the valve where the water hammer is taking place and open it.
- Wait for the waterlogged air chamber to completely drain out. This allows air to get back into the chamber and create a new ‘air cushion’.
- In some cases, the air chamber is located below the water source. If this is the case then the water source should also be drained as well. If you do not drain the water at its source before attempting to drain waterlogged air chambers they will simply continue to refill with water, making the whole process a rather pointless exercise.
In the event where taking the aforementioned steps failed to rectify your water hammer problem, there is a very good chance that your piping’s air chambers have become blocked (as opposed to simply waterlogged) – this can represent a somewhat trickier problem to solve.
By its very nature, piping is prone to accumulating all sorts of undesirables, including grime and residue left over from the various chemicals that pass through pipes as part of the routine. Blockages can occur when large quantities of such unwanted substances accumulate over time, making your pipes less capable of draining correctly. Modern, well-constructed piping generally features air chambers which are bigger than the pipe which leads to them. This can help prevent the air chamber from getting blocked. In such piping, blockages can be fixed relatively easily. Once the piping’s water supply has been cut off, the air container cap can be removed entirely. Once that is done, all you have to do clean the gunk out of the air chamber (a wire brush is probably the best tool to use) and then reattach it.
The solutions outlined above only work in relation to properly installed modern piping systems with air chambers. Older forms of piping or those which have not been installed by a professional plumber may be lacking in air chambers and, as such, said solutions will not work.
Water hammer tends to occur in areas of high water pressure. By that logic, one way of reducing its effects is to reduce water pressure levels in you piping if possible. One way of reducing water pressure levels is by having a pressure reducing valve installed in between your pipes’ water source and the location where the water hammer is occurring.
Reducing your water pressure may not be an applicable solution in all circumstances. While it can stop water hammer from occurring, having low water pressure can be a problem in itself. When your water pressure levels are too low your taps, shower etc. may not be able to give out a good supply of water when used. This is particularly problematic in relation to those faucets which are located underneath the water source. If you cannot strike a good balance of water pressure that will provide enough water from taps etc. while avoiding water hammer, then having air chambers installed in useful locations is the best answer to this conundrum.
As such works are no simple task, seeking help from a professional plumber is probably the best option available to you. Email DeWAR Plumbers or call us on our phone number, 01 514 3300, to have one of our plumbing professionals call out to you and rectify the problem.
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