I read in sci.electronics.design that Active8 <mTHISREMOVEcolasono@earth
I should have said "prevented", not "cured".
1. Find cause.
2. Eliminate cause.
See above. I meant stubs that are designed in. They eliminate the
thump when you turn off the tap. Air tanks have been added near the
main entrance as a later fix to avoid opening a wall to add a stub.
I haven't heard of one ever filling up with water so far. I'm not
sure that they're a good idea for that oscillating noise. They
might absorb it, but the plumbing would take a bunch of stress.
Anyway, we're talking about plumbing. AFAIK, my dad never hired a
hydraulics engineer when he designed buildings. And AFAIK, plumbers
just install the crap per design which these days includes stubs or
whatever they call 'em. Maybe Dad just knew WTF he was doing -
studied what engineers had already figured out. His NYC "sky
scraper" is still standing
I guess his plumbing's still ok, too.
It's a bit difficult to answer such a general question more helpfully.
Water-hammer needs an initial transient to trigger it. That could be as
simple as a tap (faucet) that turns off too rapidly. A different type
may be needed, but a restricter on the inlet (a washer with a smallish
hole in it; acts like a 6 dB pad) may be OK if the reduced flow is
acceptable.
*You* shower under reduced pressure
Another cause is unstable flow in a pipe: the pipe doesn't
remain full because the source can't supply the flow-rate required by
the drain.
Which suggests an idiot designed it or a plumber fouled up either
the initial install or a later repair.
It's much worse if the pipe has bends in it. Again, a
restricter may fix it.
The gypsies that retroed the oil furnace into the coal furnace
heated house I lived in as a kid are a prime example of fools with
tools. Instead of cutting back the hot water pipe and fitting the
furnace correctly, they installed extra elbows and short sections
to line up the new with the old. 270 degrees worth of elbows in a
area less than a ft^2. But no noise and still enough pressure -
with the right shower head. The oil line from the tank is a piece
of work, too. Imagine a copper tube poorly hand bent ( crinkle and
destroy - rhymes with Henkle and McCoy, a utilities contractor )
into a large radius arc with its highest point secured to a floor
joist with one of those brackets used to secure conduit to the
outside of a building. Then there's a light bulb that anyone over
5'-6" can run into with their head.
Sorry, back to plumbing. This is the plumbing group, right?
Oh
yeah. Impedance analogies. It's common these days to have a short
section of pipe above the tee (plumbing jargon for splitter) where
the pipe egresses the wall to supply the fixture.
Now engineers may or may not have found a generic solution to the
oscillation problem. Last time I was in a house under construction,
I saw the water main coming in to a plastic manifold and all the
pipes were supplied from that manifold. Said pipes were flexible
plastic hoses with the kind of fittings you'd see in a hydraulic
(look at your power steering pump) system. I'm thinking that this
kind of "home-run" feed (as opposed to poor feeder and tap design)
eliminates those discontinuities that would cause the aformentioned
problems. It appears to be a nice system.
