Elbow use in pool plumbing

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Elbow use in pool plumbing

Postby NewPumpGoingIn » Mon 23 Jul, 2012 15:35

When making a 90 degree turn in the plumbing, is it better to use one 90 degree elbow or two 45 degree elbows? Is there any data to support one versus the other in providing the best flow through the pipes? It would seem that a gentle curve would be better than a sharp turn, so to speak.

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Elbow use in pool plumbing

Postby czechmate » Mon 23 Jul, 2012 16:37

Either way is fine. It is water afterall.
It makes difference in pumping crude oil with impurities and friction in a metal pipelines.
The less connections means less potential leaks. There is also small 90 degree fitting available in plumbing shops.
I would not be concerned as 99 percent of plumbers are not either.
The only thing that may be potentialy an advantage is to add a "compensator" in a runs, for likelihood of a pool or ground settling. (Can be done with fitting or by bowing the pipe on longer runs).I had not done either and have not had a problem in Dallas black clay.
BTW, never lay large PVC SCH40 in very hot weather on longer runs without covering with dirt immediately. Hot weather also impedes proper gluing.
Evening cooling may pull fittings apart. (Have seen it many times on long electrical runs).
TSH Tech

Elbow use in pool plumbing

Postby TSH Tech » Tue 24 Jul, 2012 02:00

Well, you may want to consider a few factors if you are concerned about water flow. If you are plumbing pool equipment, a 90 sharp elbow with a size of 1 1/2 inch pipe, is equivalent to 7 feet of straight pipe. A 2 inch 90 degree sharp elbow is equivalent to 8 feet of straight pipe.
What does this all mean? In water flow terms, it's the amount of friction that slows down water as it passes through the pipe. Two 45's wouldn't hurt if you have space to plumb, they do have a lower water friction coefficient. If space is of concern, Waterway Plastics makes a sweeping 90 PVC coupler Sch. 40 called an Ells 90 degree PVC sweep.

I can see this being applicable to a water fountain where flow is of great importance.
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Elbow use in pool plumbing

Postby mas985 » Wed 12 Dec, 2012 22:40

2 45s have about the same head loss as a single 90 so it really shouldn't make much of a difference. When you include the glue joints, it is usually worse. However, if you really want to save on head loss, the most cost effective way is to increase the pipe diameter. Increasing from 2" to 2.5" reduces head loss by over 60% for the pipe and fittings. Far better than fiddling with the fittings.
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