Forum / THE MAIN WALL / gpm thru 2\" pipe at 50 psi

## gpm thru 2\" pipe at 50 psi (8 Posts)

• ### I think

this table is similar to what Mike was referring to.

Dave
• Don't have it with me now, but there's a table in the little black book named Pocket Reference that allows you to estimate GPM from an open pipe by measuring the horizontal distance it takes for the stream to drop x inches. EXCEPTIONAL little book.
• ### bernoulli and others

It's a free jet, pretty close to this (some rounding to get the 4): GPM=4*(the square of the diameter in inches)*(square root of the gauge pressure in psi) so GPM = 4 * 2^2 * sqrt(50) = 113GPM
• ### how did you get the 4

I was wondering how you got the 4?
• Yep. That's exactly what I was thinking of.
• ### Lenght?

It does not work like that! Use the B&G System Syzer. Example: 45 GPM in a 2 inch iron pipe, within normal design parameters can pass 48 GPM with a loss of 4.5ft (aprox 10 PSI) per 100 ft of pipe. I looked up a pressure loss table. At 50 PSI ( pressure loss) per 100 FT, it is a flow of 116 GPM which is entirely unrealistic. It surpases the maximum recommended velocity of 10 FPS! The lenght of the pipe is the most important factor, if you are working either with a pump or city pressure on an open system.
• ### gpm

look up  water flow through hose - Engineering Tool Box   there is a curve.
RJ
• ### gpm thru 2\" pipe at 50 psi

Wondering what the gpm's are on a open ended 2" pipe at 50 psi? No friction loss or head. Just looking for a rough measurement.
•