fps/gpm

Brad White_26

of the pipe. Q x A

4 FPS in a 3/4" pipe and 4 FPS in 12 inch pipe have *slightly* different flow rates ;)

There are abundant charts and probably shorter formulas, but I like to break things down.

Getting to gallons per minute you have to convert.

If you know the cross sectional area in inches:
(Pi R Squared) will give you square inches.

That x 12 will give you cubic inches

Divide by 1728 will give you cubic feet

x 7.49 will give you gallons per foot of pipe. (There are 7.49 gallons per cubic foot you see.)

x your velocity in FPS gives you gallons per second.

x 60 gives you gallons per minute.

Thus, a pipe with a volume of one gallon per foot at 4 FPS:

1 gallon/foot x 5 fps x 60 seconds per minute = 300 GPM.

[Trivia: As a benchmark reference size, 5 inch pipe has very close to one gallon per foot.]


If you can latch on to a copy of "Camerons' Hydraulic Data" (Still published by Ingersol-Rand? Hope it is not out of print), you will find what you need. There are other resources too, published tables from ASHRAE and their neat little pocket reference handbook. Might be something on the Shop for Books and More link on this site too. B&G System Sizer, others.

In general terms, the ID of standard weight steel pipe and most copper pipe is close enough to nominal. In steel pipe the ID is roughly nominal until you get to 14 inch and above, then it is OD. (A 16 inch IPS has an ID of 15.

Now, convert FPS to Furlongs per Fortnight, and I will really be impressed.

OK... I'm done... :)

Brad

Bob Sweet

Help with equation

feet per second / gallons per minute. What is the equation to solve for this? Thanks!!

Bob Sweet

Thank You!

Thats exactly what I needed.

Timco

http://www.convert-me.com/en/

Paul Rohrs

Sage advice Brad

You can also download a "System-Syzer" wheel from Bell & Gossett. Here is the link. Good tool to have around.

http://www.bellgossett.com/software.stm


Regards,

PR

Sorry Brad, I just re-read you post, you were way ahead of me. Department of Redundancy Department signing off.

Biggerstaffradiantsolutions.com

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

Bob Sweet

System Syzer

Don't feel bad Paul, I've got the "System Syzer" on my computer and didn't realize it had what I was looking for. It's official I'm a bonehead!!

bob_50

Brad

one furlong in one fortnight is about .0005 fps. I don't think this is an adequate velocity to keep the air intrained.;>) bob

Brad White_9

Dang, Bob

No wonder my Spirovent is unemployed...

Brad White_9

After all that????

And YOU feel badly???

Jeeesh!

I needed the exercise anyway!

Cheers!

Brad

nb_4

formula short and sweet

here it is;

V=0.408 x [ F/D squared ].
Where V = velocity in feet per second, F = flow rate in gallons per minute and D = true inside pipe diameter.

e.g. 3/4" copper tube type M, inside diameter 0.81"

0.81 squared = 0.656.
F = let's say 4gpm 4 / 0.656 = 6.098.
0.408 from above x 6.098 = 2.49 feet per second.

Hope this helps.

Brad White_27

That one

is going in my spreadsheet. Thanks!

rb_6

...and here is the original System Syzer

rb_6

...and here are two originals

one is the first System Syzer and the other a good friend to all.