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Frictional Loss of HRJ


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Are you looking for what would be the friction factor in the usual pressure loss due to friction equation? If that's the case, not a scooby doo! Consult the manufacturer maybe.

Anyhow, who likes trains?!..........

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So, just chiming in with this, good old christmas reading material

ive copied it from a doc i submitted ages ago,  which eventually led to my FRS switching to 22mm tubing. It also led to us prohibiting the use of extended hosereels for internal work at building fires

Doesn't answer your question, but all the info is there for you to work it out! 


Formula:   Pf  = 9000 flL²

Key for formula below

P = Pressure loss in bars
f =  Degree of internal roughness of a particular hose or pipe is referred 
       to as its friction factor (f) or co efficient of friction.
l =  Length of hose in metres 
L = flow rate in Litres per minute
d = hose diameter in mm

So, for 22mm, 54m not extended assuming 200 LPM the pressure loss is 24.5186307 BAR

For 22mm, 108m extended assuming 200 LPM the pressure loss is 49,0372615 BAR

And...for 19mm, 54m not extended assuming 120LPM the pressure loss is 18.3714787 BAR

For 19mm, 108m extended, assuming 120LPM the pressure loss is 36.7429574 BAR.

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That's the formula I've known, but the friction factor element escapes me for hose reel.

I found the friction factor for 45, 64 and 90mm is apparently the same as it's to do with the roughness of the inside tubing, at about 0.005. I wouldn't be surprised if hosereel tubing is the same. 

Plug that in with the numbers supplied and I doubt you'd be far off.

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