In article ,
Chris Hogg wrote:
If such exists, it's not used. But I doubt its existence;
we're right out in the country. Whenever the water 'goes
off', we can expect an hour or so of explosive
spluttering and coughing from the cold taps as the air is
forced out under pressure. I sometimes fear for the
joints in the pipes, it can be so violent; the 'rigid'
mixer tap in the kitchen (i.e. not one on a flexible
hose) physically recoils! We tend to flush the loos
repeatedly to clear the air, as it seems to be less
violent to do it that way. It also gets rid of any
discoloured water.
I seem to remember that liquid (water) does not compress,
whereas gas (air) can be fairly easily compressed. But
inside the pipes, the air will be compressed until its
pressure is equal to the water. When the compressed air
reaches the open tap it just decompresses and expands as it
is forced out by the water behind.

As the pressure of the air or water will not be more than
that of the water, your pipes should be all right.

--
John Mulrooney
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There are 2 true symptoms of dementia; one is forgetting what you are saying, the other is forgetting what you are saying ...