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flow rate loss through 10 feet of 3/4" k copper

flow rate loss through 10 feet of 3/4" k copper

flow rate loss through 10 feet of 3/4" k copper

(OP)
Hi Guys have a wired question to ask.

need to know what the flow rate would be for the following:
Main Line 10"
Service line first 10 feet to curb valve is 3/4"
rest of service to house is 1-1/4" for 55 feet.

what is my actual flow rate at the end of the 1-1/4" line b/c of the first 10 feet being 3/4"
everything is k copper and static pressure is 85 psi at the end of the line.

totally stumped on this one
 

RE: flow rate loss through 10 feet of 3/4" k copper

(OP)
forgot to add that i need to have a minimum operating psi of about 55 psi
and this is a water service line from the town supply

thanks for your help in advance
 

RE: flow rate loss through 10 feet of 3/4" k copper

use Hazen Williams equation to calculate the headloss. Add in a minor loss for the meter and any other fittings.

RE: flow rate loss through 10 feet of 3/4" k copper

(OP)
i don't know if i have all the information to complete that,  any help would be appreciated.

thank you in advance

RE: flow rate loss through 10 feet of 3/4" k copper

you may be able to get a maximum of 9 - 10 fps through the copper line which would give you maybe 13 gpm

RE: flow rate loss through 10 feet of 3/4" k copper

(OP)
i thought it would be much more, given its only traveling through 10 feet of pipe it would have very little friction loss.
 

RE: flow rate loss through 10 feet of 3/4" k copper

You would probably be able to get 35 gpm through the pipes with a headloss of approximately 62 psi. If you started with 85 psi, that would leave you with around 23 psi residual pressure. The velocity in the 3/4-inch line would be 25 ft/sec.

http://www.dsginc.biz/documents/maxflow_chart.pdf

http://www.dsginc.biz/documents/maxflow_chart.pdf
Not sure what is the practicality of this theoretical calculation.

If you exceed the recommended velocity of 8 ft/sec in the copper tubing, then the copper tubing will corrode away in a short time.

 

RE: flow rate loss through 10 feet of 3/4" k copper

(OP)
bimr,

thank you for your real work answer,  i noticed on the sheets you provided that it has an actual 50 gpm rating but that's with an open flow and no resistance.  i think i will design the system around 20 gpm and be on the safe side.

thanks for all the input guys.

RE: flow rate loss through 10 feet of 3/4" k copper

Not really sure what application that you have, but it must be noted that you will be operating well outside of the normal water velocity range of 3-8 ft/sec.

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