How can i find the relative roughness of fire hose?
How can i find the relative roughness of fire hose?
(OP)
Below is the hose description
Elastomeric lining, Synthetic fibre reinforcement and elastomeric coating on the reinforcement.
with diameter 3 inch
and length 30m
thanks
Elastomeric lining, Synthetic fibre reinforcement and elastomeric coating on the reinforcement.
with diameter 3 inch
and length 30m
thanks





RE: How can i find the relative roughness of fire hose?
The fire fighting industry uses a slightly different approach to calculating pressure drops from that used by process and mechanical engineers. I re-jigged the data from page C-6 of the referenced article to work out that the average roughnesses were between 0.02 and 0.05 mm. For typical fire hose sizes this variation makes very little difference to the calculated pressure drop and for my AioFlo program I have used 0.05 mm.
Note that these values do not apply to spiral reinforced hoses which have a bellows like internal surface.
Katmar Software - AioFlo Pipe Hydraulics
http://katmarsoftware.com
"An undefined problem has an infinite number of solutions"
RE: How can i find the relative roughness of fire hose?
im trying to calculate the pressure drop with regards to the distance covered with a specific hose diameter(3 inch),
and im using the equation
head loss(hl) = (fl(v^2))/2Dg
and then used p= (rho*g*hl)
*
I've used f as 0.017
is this a right approach?
secondly I've checked on web, and ive found this formula.
check it out!
http://www.fireengineacademy.com/training/friction...
which approach is much more accurate?
RE: How can i find the relative roughness of fire hose?
Because Hazen-Williams is easier to use, and has been around longer, it seems to be the equation recommended (or even mandated) by fire protection authorites world-wide. I don't do a lot of fire water work, but when I do I use Darcy-Weisbach to be sure that I have got the correct pipe sizes or flow rates, and then I re-run the calcs with Hazen-Williams to satisfy the authorities.
Katmar Software - AioFlo Pipe Hydraulics
http://katmarsoftware.com
"An undefined problem has an infinite number of solutions"
RE: How can i find the relative roughness of fire hose?