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# What is the formula to find pressure loss in fire fighting pipe lines?

Updated: 8/11/2023

Wiki User

14y ago

pips are generally cylindrical in structure of amount of heat loss through pipe is given by the formula Q= 2 pi k L(T1-T2)/ln(r2/r1) where k=conductivity of material of which pipe is made T1= temperature of inside layer pipe T2=temperature outside layer of pipe L= length of pipe r1= inner radius r2=outer radius ln=natural logrithem pi=22/7 the above condition applies for steady state flow,single layer over cylinder and neglecting conductivity convection to take conductivity convection into account term Q* must be added Q*=2 pi L{ r1 hi(Ti-T1)+r2 ho(T2-To)} hi=convective coefficient for inside layer ho=convective coefficient for outside layer Ti= temperature of inside space of pipe To=temperature of outside space of pipe for unsteady condition there is another formulaa

Wiki User

14y ago

Wiki User

14y ago

The British fire and rescue services use the following formula for calculating the pressure loss due to friction in firefighting hose: Pf = 9000 f l L2 / d5 bar where Pf is the frictional loss of pressure, in bar

f is the friction factor

f = 0.005 for 70 mm or 45 mm hose

f = 0.007 for 90 mm hose

(for 90 mm hose it is higher to allow for losses in the couplings, which are but 64 mm diameter)

l is the length of the hose line, in metres

L is the flow rate, in litres/minute

d is the hose diameter, in millimetres The formula is approximate, and relates to internally lined hose in 25 metre lengths. You will find the formula in the old Manual of Firemanship, Book 7, Hydraulics, pumps and pump operation. David Hayward, former MIFireE

Wiki User

14y ago

The thickness of the pipe will effect the loss rate.

Best thing to do is buy thermal isulating foam, normally comes in tubes will a slit down one side so it can be slid over the pipe easily. Also depending on the the fluid inside the conduit ( pipe ) and diameter, ambient temp, and location, you may be able to use a product such as heat trace. It is an electrical wrap that uses voltage and amperage to create heat to shield from the outer elements...

Wiki User

13y ago

Infrared Cameras are possible to rent, they will show the amount of heating coming off and thus it's efficiency.