In . 97.131,
Zootal typed:
"EXT" wrote in
anews.com:


"Existential Angst" wrote in message
...
"Zootal" wrote in message
. 97.131...
mike wrote in



On Feb 10, 4:14 pm, Zootal wrote:
Here is a somewhat more esoteric question. I have to snake around
some stuff, and I can do it with two 90 degree elbows, or two
"45" degree elbows. In the end, will using the 45 elbows give
noticably increased wat
er
flow? The pipe goes into a shower valve that is 1/2 inch, and the
interio
r
of the valve is even more restricted, so I'm thinking in this
case it won
't
make any difference.

But out there in the real world where we bend this way and that
way, does it matter how sharp the bend is wrt water volume?

Don't worry about it.

But I can tell you're an obsessive type, so if you want, you can
look up the equivalent friction loss of a 90 degree and 45 degree
elbow with regard to pipe diameters in a fluid dynamics book at
the library or on Google books if you don't believe me. From
what I recall, neither is significant, and you won't notice a
difference.

Worry about low-flow shower heads instead.

I am cursed with curiosity for just about everything... ggg what
if...? what if ... ? what if ... ?

Proly not the biggest deal, but certainly two 45s are more elegant.
Slightly more expensive than one 90, but certainly more correct.
And the effect of pressure loss will be proportional to flow --
truly insignificant with a low-flo shower head, perhaps noticeable
in something like a high-flo garden hose..
90s in air conditioning have a pretty substantial effect, and 45s
would be a good idea there.
--
EA


Personally, I always use a 45 degree elbow when I have a choice. For
example to change directions and elevations at the same location,
such as when a pipe is traveling parallel to and between joists and
must make a 90 degree turn and drop below the joists, I always use
the 45 to angle down to below the joist and then a 90 to turn across
the bottom of the joist. If I am going around something such as
another pipe where one would need 4 90s to get around the
obstruction, I always use 4 45s to accomplish it, if the obstruction
is only slight, I will try to use "street" 45s to accomplish the
offset. To me it looks better, it does improve the water low and
also reduces noise at a high water flow.



Ah, there is something I hadn't thought of. How much more likely are
the pipes to hammer because of 90 degree elbows, versus 45? I would
bet that 45's are quite unlikely to cause hammering problems. though
two 45's in a row might hammer just the same as a 90. Just guessing -
I'm way outside of my area of expertise here. I don't want to do
plumbing long enough to actually get good at it :-P

Not likely to make any difference, I don't think. Hammering is more the
effect of quickly turning a faucet off quickly which lets the water's
inertia try to move the whole pipe system and thus "hammers". If anything,
90 would improve it by adding some damping or slowing to the "hammer"
action.

HTH,

Twayne



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