https://www.dropbox.com/s/hr544ox9envif6d/reza_vel_eu.xlsx?dl=0
Reza, I know the European Code has some velocity restrictions, and it occurred to me to suggest that in those instances where the maximum velocity is exceeded you might ask your AHJ to consider using a different C-Factor in the Hazen-Williams friction loss equation, for those pipes where the max is exceeded. Referring to the spreadsheet, K-11 shows the I.D. of 50mm schedule 40. Q at B-10 is 814 LPM, and the velocity at D-10 is 6.27 m/s. The C-Factor at F-19 is 120. In NFPA 750 (2015) there is a formula for solving for the friction factor in Darcy-Weisbach f.l. equation based on the Reynolds number, velocity, and C-Factor, but I used the "Swamee-Jain" equation for the friction factor, so I re-arranged to solve for C-Factor, at G-19. For the Absolute Roughness, input at B-22, if you choose the middle of the range for Slightly Corroded and look at the Pf/m for both the H-W and D-W calc you see they are close, and the calculated 'equivalent' C-Factor is 119. Now if you double Q (the velocity) you see the Pf/m diverge and the calc'd C drops to 113. Warning Reza!! This whole thing is entirely unvetted. I have ask for some QC and/or feedback, but no luck so far. thanks for listening, Brad Casterline, NICET IV Fire Protection Division FSC, Inc. P: 913-722-3473 [email protected] www.fsc-inc.com Engineering Solutions for the Built Environment
_______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org
