Water flow speed

Water flow speed

PostBy: grumpy On: Sun Dec 09, 2012 9:17 pm

Ok, I need help with this, and yes I did google it and found lots of info but not what I'm looking for. What I am trying to figure out is how fast as in feet per second would water flow at 40psi with no restriction at the end of the pipe?

This would be 1/2 inch PEX, if that matters, anyone here good with math?
grumpy
 

Re: Water flow speed

PostBy: steamup On: Tue Dec 11, 2012 1:29 pm

You need to know the length of the pex and number of fittings to figure this out.

But why would you need to know this?
steamup
 
Stoker Coal Boiler: Axeman-Anderson AA-130, Keystoker K-6
Hand Fed Coal Boiler: HS Tarm 502 Wood/Coal/Oil
Coal Size/Type: pea, buck, rice

Re: Water flow speed

PostBy: coalkirk On: Tue Dec 11, 2012 1:46 pm

I think he is referring to domestic water systems and not hydronic. ???
coalkirk
 
Stoker Coal Boiler: Harman VF3000
Coal Size/Type: antrhcite/rice coal


Re: Water flow speed

PostBy: steamup On: Tue Dec 11, 2012 5:20 pm

I figured he would be talking about domestic. However, there is no need to figure open flow that way. You need residual pressure at the end of the pipe to be of any use, so different design standards would apply.

The opposite approach should be taken. The pipe should be sized for the flow and pressure drop. The size should also limit the velocity to under 8 feet per second to be reasonable. 10 feet per second and more can cause errosion of the pipe materials.

However, for giggles, here is a forum that talks about the same calculations.

http://forum.pipeflowcalculations.com/v ... ?f=3&t=218
steamup
 
Stoker Coal Boiler: Axeman-Anderson AA-130, Keystoker K-6
Hand Fed Coal Boiler: HS Tarm 502 Wood/Coal/Oil
Coal Size/Type: pea, buck, rice