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idontknow · Guest

Pressure loss vs hose dia vs length

RCIA Founder

idontknow wrote:

Been trying to work out what the pressure loss is for certain lengths and diameter's of hoses. I'm just confused as to how to work it all out.

I found this site with a graph http://www.engineeringtoolbox.com/pvc-pipes-friction-loss-d_803.html and if I am reading it right it seems that @ 5 gpm flow you loose around 20psi per 100 feet of 1/2 inch hose.

for 200' hose that means a loss of up to 40psi???? if you had a pump putting out 60psi that means you would only end up with 20psi at the end of the hose

is this right? Is there a math genius here to help?

This IS correct, and one reason we suggest bigger hose diameter then 1/2 inch for roof cleaning use.
I had a link to an online flow and pressure loss calculator using pipe instead of hose.
BTW, coiled hose has additional loss, and thats why we suggest uncoiling your all your hose when maximum shooting of the roof cleaning chemical is needed.

white fox · Guest

So just because you don't need 3/4 in hose for the volume you would be better for the flow that makes sense glad I didn't order mine yet

RCIA Founder

white fox wrote:

So just because you don't need 3/4 in hose for the volume you would be better for the flow that makes sense glad I didn't order mine yet

I personally would not use less than 5/8 on a 12 volt pump, and 3/4 is even better!
!/2 will work, but you lose both pressure and flow, meaning it will slow you down, you pumps works harder, runs hotter, and will just not spray as good, or shoot as far.
A 12 volt pump has very little pressure anyway, why pizz it away ?

Sal · Guest

I disagree, I use a fatboy with 1/2 inch hose and I cover the roof in no time and use half the love that 3/4 use.

Baltimore MD Roof Cleaning 410-482-4367 · guest

lol

The Roof Cleaning Institute Of America Training & Certification Forum "Find A Certified Roof Cleaner Directory"

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"Find A Certified Roof Cleaner Directory"