C is actually the coeffficient of the flow hydrant. Common coefficients for fire hydrants 2.5" outlets are .9(rounded), .8 (squared), and .7 (squared protruding). You wil have to reach into the barrel of your flow hydrant to feel what the inside of the outlet feels like. This information is in the NFPA pamplet.
Thank god we have flow chart that give you all of the gpm. All you need is the size of your play pipes and what your pitot gauge pressure tell you. 10 psi on your gauge using a 1.75 play pipe will give you 288 gpm. That is using a chart and no math involved
I have to questions, first what instrument do we use to measure the pressure in a flow test? I can't find it, and the second the diameter you are using to calculate is the hydrant diameter or the nozzle exit diameter??
I don't know the name of it but it is from NFPA 291, "Recommended Practice for Fire Flow Testing and Marking of Hydrants". It is located in the 'Determination of Discharge' section.
C is actually the coeffficient of the flow hydrant. Common coefficients for fire hydrants 2.5" outlets are .9(rounded), .8 (squared), and .7 (squared protruding). You wil have to reach into the barrel of your flow hydrant to feel what the inside of the outlet feels like. This information is in the NFPA pamplet.
Thank god we have flow chart that give you all of the gpm. All you need is the size of your play pipes and what your pitot gauge pressure tell you. 10 psi on your gauge using a 1.75 play pipe will give you 288 gpm. That is using a chart and no math involved
C should be the loss due to the coefficient of the outlet.the roughness of the outlet
I have to questions, first what instrument do we use to measure the pressure in a flow test? I can't find it, and the second the diameter you are using to calculate is the hydrant diameter or the nozzle exit diameter??
How you choose the diameter high dia or lower dia
helpful
Nice video. Check out Preplan Files cloud application - this is part of the hydrant testing module. No math!!
Is the C factor always 1?
Can anyone tell me the name of the formula
I don't know the name of it but it is from NFPA 291, "Recommended Practice for Fire Flow Testing and Marking of Hydrants". It is located in the 'Determination of Discharge' section.