pvc pipe size question

Mar 06, 2005 9 Replies

Hi there:



Sorry for intruding but can I ask a question. Can someone tell me please how much water roughly will travel through PVC 40 pipe by gravity (no pump), if it's vertical (roughly) and only about 6 ft high? In a few different diameters? I've looked on the internet and I can only find tables of friction loss and tables of maximum flow rates. I just want to get an idea for an aquarium system that I'm building. i.e. with 1/2", 1", 1.5", etc.



I appreciate any and all help. Quietreef


"quietreef"

I don't think plumbers would know this. Try looking for "'alt.physics" or something.

The formula for figuring volume of a cylinder is 2 pi r squared times height.

In the case of 1/2" inch pipe 72 inches high that would be (2 x

3.14 x .25squared) x 72. Which would give you 28 1/4 cubic inches. 1 gallon(US) is 231 cubic inches. So that would give you .1223 of a gallon, or about a pint.

That's how much water it will hold. How much water will travel through the pipe depends on whether it will be at full volume for the pipe and how long a period of time you are looking at. For a 6' length of pipe, friction loss is minimal for an aquarium.

Are you asking how long for a certain amount of water, or how much water in a certain amount of time?

Hi there:

I'm looking for rate. If the water is falling by gravity with no pump or back pressure, roughly, how many gallons/hour will I get in a 1/2" pipe or a 1" pipe, which I assume is 2X whatever the 1/2 number is. Now that you've laid it out so nicely, I should be able to figure it out, thanks.

quietreef

ebo walker wrote in news: snipped-for-privacy@walker.com:

You mixed up the formula. It is pi r squared NOT 2 pi r squared. 2 pi r is for circumference.

You need a different formula to figure out the flow rate anyway (but you willuse this calculation also). You need the pressure of the water. In a vertical pipe you get 1 PSI of pressure for every 2.33 feet of head (height). You'd be at about 2.5 PSI at 6' (without a calculator). I am still looking for this formula, but if will give you cuft/sec. Then you can use 7.48 gal/cuft of water to calculate gal/sec.

"Eric G."

Hey, by this time, he could have built the stupid thing, bought the pipe in several sizes, and timed it by himself.

Yeah, I think I'll probably just do this. It's easy enough to time it myself, but thanks anyway.

Quietreef

"Mike Grooms" wrote in news:h58Yd.3300$ snipped-for-privacy@fe37.usenetserver.com:

I never said I was quick :-)

I have held off on this post because it is soo stupid. Fill the god damn tub and time it darining dont build a thing. There are groups dedicated to fish tank systems.

Be nice.....he may be making a home for Hots girl....Wanda !

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