GPH on drains

[dawgface]

How many gallons per hour will (2) inch and half drains handle??

 

[rjrgroup]

2" pipe can</em> handle 150gal per minute (50-150maximum). I'm not sure how the curves affect the numbers but I would guess a huge amount per 90 degree bend.
wait, 2" or 2"1/2?
or two 1 "1/2?
My bad...

Edit: <span style="font-size: 1-1px">Assume Gravity to Low Pressure. About 6f/s flow velocity, also suction side of pump</span> <span style="font-size: 1-1px">Assume Average Pressure. (20-100PSI) About 12f/s flow velocity</span> <span style="font-size: 1-1px">Assume "High Pressure" PEAK flow. About 18f/s flow velocity*</span> Sch 40 Pipe Size ID
(range) OD GPM<span style="font-size: 1-2px">
(with minimal pressure loss & noise)</span> GPH<span style="font-size: 1-2px">
(with minimal pressure loss & noise)</span> GPM<span style="font-size: 1-2px">
(with minimal pressure loss & noise)</span> GPH<span style="font-size: 1-2px">
(with minimal pressure loss & noise)</span> GPM<span style="font-size: 1-2px">
(with significant pressure loss & noise)</span> GPH<span style="font-size: 1-2px">
(with significant pressure loss & noise)</span> 1/2" .50-.60" .85" 7 gpm 420 gph 14 gpm 840 gph 21 gpm 1,260 gph 3/4" .75-.85" 1.06" 11 gpm 660 gph 23 gpm 1,410 gph 36 gpm 2,160 gph 1" 1.00-1.03" 1.33" 16 gpm 960 gph 37 gpm 2,220 gph 58 gpm 3,510 gph 1.25" 1.25-1.36" 1.67" 25 gpm 1,500 gph 62 gpm 3,750 gph 100 gpm 5,940 gph 1.5" 1.50-1.60" 1.90" 35 gpm 2100 gph 81 gpm 4,830 gph 126 gpm 7,560 gph 2" 1.95-2.05" 2.38" 55 gpm 3300 gph 127 gpm 7,650 gph 200 gpm 12,000 gph

 

[roundman]

There are some calculators here. Fro drain you could work backwards but like stated elbows will change everything.

 

[rjrgroup]

Sorry, it didn't paste like it was asked,haha.
Low pressure (gravity)
1.5" = 35 gpm 2100 gph
I'm assuming this is at sea level as well so (reduction) of +/- 10%.

 

[rbredding]

ja4207;629408 wrote: how many gallons per hour will (2) inch and half drains handle??

lots....

 

[grouper therapy]

About 1325gph each -no head loss calculated but will have some static loss in certain configurations(long horizontal runs)

 

[rbredding]

 

[grouper therapy]

Rbredding;629542 wrote: http://flexpvc.com/WaterFlowBasedOnPipeSize.shtml">A good reference site for PVC...</a>[/QUOTE]
If you use this chart make sure and read the chart reference to the right as will explain then numbers a little better if you don't it will have you think that an 1.5" pipe will drain 2100gph which it might under siphon.

 

[rbredding]

the reality is that pvc drains will only pull water out in this volume IF they are fully under water at the time...

because our overflows are actually weirs, the only way to increase your drainage rate is to increase linear distance where the water "falls over the edge" of the pipe..

for instance.. a 1" stack of a durso with a 1" bulkhead will drain X volume/hr, but if you upsize that 1" pipe to 2" for the top half of the durso, it will drain more water (through the same 1" pipe penetrating the bulkhead) because there is a longer leading edge for water to fall over in order to go down the drain.. (which is the limiting factor of the drain, not the size of the bulkhead as many think)

I don't know the calculations to be used, because I cannot find a calculation for predicting horizontal flow across the water's surface (as it flows over the leading edge of the drain)


I HAVE, however, seen this in practical application in storm drainage inlet systems used in parking lots and yard inlets in water quality/water detention ponds

 

[grouper therapy]

That makes sense since the distance around the pipe determines the leading edge which is where the water enters and starts it's fall. Yea I with you on the chart from flexpvc it would have to be a submerged/ siphon to handle that kind of flow.

 

[rbredding]

grouper therapy;629708 wrote: That makes sense since the distance around the pipe determines the leading edge which is where the water enters and starts it's fall. Yea I with you on the chart from flexpvc it would have to be a submerged/ siphon to handle that kind of flow.

incidentally, I found that I was able to increase my return flow by increasing the size of my dursos

Here is the original durso (you can see the water draining and it barely keeping up)
http://www.atlantareefclub.org/forums/attachment.php?attachmentid=21895&d=1265120032" alt="" />


Here is a side by side comparison of my modified durso (obviously, original on the left)

[IMG]http://www.atlantareefclub.org/forums/attachment.php?attachmentid=22336&d=1266539009" alt="" />