How to Guide

43
Pressure Flow
Friction loss through PVC pipe is normally obtained by using
UIF)B[FO8JMMJBNTFRVBUJPOTIPXOCFMPXGPSXBUFS
f = 0.2083 x
(
100
)
1.852
x Q
1.852
C di
4.8655
8IFSF
f GSJDUJPOIFBEMPTTJOGFFUPGXBUFSQFSGFFUPGQJQF
C DPOTUBOUGPSJOTJEFQJQFSPVHIOFTT$GPS"#4
and PVC pipe)
Q nPXJO64HBMMPOTQFSNJOVUF
diJOTJEFEJBNFUFSPGQJQFJOJODIFT
Friction Loss Through Fittings
The friction loss through fittings is considered to be equivalent to the loss through a certain number of linear feet of pipe of
UIFTBNFEJBNFUFSBTUIFmUUJOHT5PEFUFSNJOFUIFMPTTUISPVHIBQJQJOHTZTUFNBEEUPHFUIFSUIFOVNCFSPGiFRVJWBMFOUGFFUw
calculated for the fittings in the system.
5IFDIBSUCFMPXTIPXTBQQSPYJNBUFGSJDUJPOMPTTFTJOFRVJWBMFOUGFFUGPSBWBSJFUZPG4DIFEVMF17$BOE$17$mUUJOHT
PGEJGGFSFOUTJ[FT
The table on page 47 shows friction heads in feet and friction losses in psi for schedule 40 pipe. It also shows the gallons per
NJOVUF(1.BOEWFMPDJUJFTJOGFFUQFSTFDPOEGPSWBSJPVTQJQFTJ[FT
Fitting
1
⁄2 ”
3
⁄4 ” 1 ” 1
1
⁄4 ” 1
1
⁄2 ” 2 ” 2
1
⁄2 ” 3 ” 4 ” 6 ” 8 ”
Tee (Run) 1.0 1.4 1.7 2.3 2.7 4.3 5.1 6.2 8.3 12.5 16.5
Tee (Branch) 4.0 5.0 6.0 7.3 8.4 12.0 15.0 16.4 22.0 32.7 49.0
90° Elbow 1.5 2.0 2.5 3.8 4.0 5.7 6.9 7.9 12.0 18.0 22.0
45° Elbow .80 1.1 1.4 1.8 2.1 2.6 3.1 4.0 5.1 8.0 10.6
 .BMF'FNBMF"EBQUFS           
Approximate Friction Loss For PVC and CPVC Fittings In Equivalent Feet Of Straight Pipe
Water Velocities
8BUFSWFMPDJUJFT JO GFFU QFS TFDPOE NBZ CF DBMDVMBUFE BT
follows:
V = 0.408709 Q
di
2
8IFSF
V WFMPDJUZJOGFFUQFSTFDPOE
Q nPXJO64HBMMPOTQFSNJOVUF
diJOTJEFEJBNFUFSPGQJQFJOJODIFT
DESIGN & ENGINEERING DATA