Pipe Sizing Charts and Flow Rates

[CHOMPERS]

Oh, 5400gph is 90 gpm. 9600 is 160 gpm.

 

[CHOMPERS]

For the cross sectional area of pipe you used; Pie multiplied by the radius squared............I always though is was suppost to be
pie multiplied by the diameter of the pipe not the radius squared...
Any one know for sure?????????

LOL, you got it right the first time. It is "pie are square". To use the diameter, you still need to square the diameter and then divide by four.

 

[tthanatoss]

Great post it answers alot of questions for me as I'll be starting my own DIY filter system pretty soon

 

[necrocanis]

A three inch pipe will give you 5400 gph. A four inch pipe will give you 9600 gph. Are the two main pumps going to be 5000ish each or a total of 5000ish? If you need to use four inch pipe for the non-pressure plumbing, you can use sch20 or sewer parts to save a bunch of money. Sewer parts aren't rated 'pottable' obviously, but they are made on the same machines as the pottable parts and are made using the exact same pvc.

Both pumps are in the 5000 gph range each. I'll look into the sewer pipes. Thanks alot!

 

[CHOMPERS]

I can't wait to see it in operation.

 

[AquariumNerd]

necessary pipe diameter also depends on pressure and allowable head loss.

 

[Jgray152]

necessary pipe diameter also depends on pressure and allowable head loss.

And you thought you were trying to be smart huh

The flow rates are for...

Maximum Gravitational Vertical Flow

 

[chemicall]

Min. Vertical Length
1/2 = 2"
3/4 = 5"
1.0 = 9"
1.25= 14"
1.5 = 20"
2.0 = 36"

Just one question about the Min vertical length in a DIY overflow.
Where does the minimum vertical length come into play?

For instance with say 1.5" piping would 20" of pipe be needed after the overflows output to achieve maximum flow?

Or does the overflows pipe AFTER the syphon going down the backside of the tank help contribute towards this 20" ?

Just not sure...

Thanks

 

[mr.reef24]

I made a really nice chart in Excel but it turns into a mess when copying it here, so here are smaller charts and their explanations:

Cross Sectional Area (in square inches) - Pipe sizes vs. their cross sectional area. Useful for dividing flow between pipes.
size __area
1/2 = .1963
3/4 = .4418
1.0 = .7854
1.25= 1.227
1.5 = 1.767
2.0 = 3.142

Maximum Gravitational Vertical Flow - This is what we look for when sizing drains or DIY overflows. The flow under the power of gravity reaches a maximum in the same way an object reaches Terminal Velocity as it falls through the air. The gravitational force is countered by the waters viscosity (resistance to flow) and the frictional resistance of the pipe. The viscosity creates a minimum vertical length to acheive the maximum flow. If the vertical pipe length is less than the minimum, the flow rate will be somewhat less than the pipes maximum potential.
size _GPM __GPH
1/2 = 2.50 = 150
3/4 = 5.63 = 337.5
1.0 = 10.0 = 600
1.25=15.6 = 937.5
1.5 = 22.5 = 1350
2.0 = 40.0 = 2400

Min. Vertical Length
1/2 = 2"
3/4 = 5"
1.0 = 9"
1.25= 14"
1.5 = 20"
2.0 = 36"

Frictional Head Loss per 90 (measured in Feet of Head)
size_ head loss
1/2 = .00970
3/4 = .00220
1.0 = .00386
1.25= .00602
1.5 = .00878
2.0 = .00156

Anyway... Each measurement is at the pipes maximum flow rate in the Vertical Flow Rate chart. When calculating the loss for the pump side, these values are slightly more.

There is a very conservative rule when estimating head loss. It is one foot of head per fitting. This rule does not take into account flow rates, pressure, actual frictional losses, etc. It does not have to because it is too conservative. If you multiply any of the above head losses by one thousand fittings, you will be very surprised at the actual head loss. (hint: just move the decimal to the right three places.)



Gravitational Horizontal Flow This is for horizontal applications that do not rely on a pump, or the force of a vertical pipe. These flow rates are considerably less than the vertical rates because gravity does not offer a significant horizontal force. It is a balance of gravity and the viscosity vs. the cross sectional area of the pipe.
size_ GPM
1/2 = 1.563
3/4 = 3.517
1.0 = 6.253
1.25= 9.769
1.5 = 14.07
2.0 = 25.0

In this application, you would use the chart for Vertical Flow.

In this application, you would use the chart for Horizontal Flow.

that is a great information where did you obtain it from? just curious I will be able to really use this thanks a MILLION.

mr.reef24

 

[Elephino]

So I'm getting around to building a permanent water pick-up/return for my 125. I'm reading this and I just want to make sure I've got it right.

I have a magdrive 950 that should do a little over 800 gph at 3 feet. According to the numbers in the first post I need 1.25" pipe for this?