Transcription of Friction Losses in Pipe Fittings Resistance Coefficient K ...
1 Friction Losses in Pipe Fittings Resistance Coefficient K (use in formula hf = Kv /2g)FittingLDNominal Pipe Size 11 1 22 -3468-1012-1618-24K ValueAngle Valve Valve Branch Valve Valve 3-Way Elbow90 radius 90 Return Bends, Pipe Bends, Flanged Elbows, Butt-Welded Elbowsr/d= 1 of 5 Friction Losses in Pipe Fittings6/13/01 Mitre Bendsa=0 : Fittings are standard with full Velocity for Full Disc LiftNominal Pipe Size 11 1 22 -3468-1012-1618-24 General ft/secWater ft/secK ValueSwing Check Check Disc Check Valve with Strainer Poppet Valve with Strainer Hinged Pipe SizesK ValuePipe ExitProjecting Sharp-Edged 2 of 5 Friction Losses in Pipe Fittings6/13/01 K values given below are for making estimates of Friction loss in cases not covered in the previous tables.
2 Pipe EntranceInward Entrance < of FittingK ValueDisk or Wobble - 10 Rotary Meter (Star or Cog-Wheel Piston)10 Reciprocating Piston Meter15 Turbine Wheel (Double-Flow) Meter5 - w/Corrugated Inner - times value for smooth bendExample: Determine L ( Friction loss in pipe Fittings in terms of equivalent length in feet of straight pipe). Assume a 6" angle valve for Schedule 40 pipe size. Select the appropriate K value for such and select D and f for Schedule 40 pipe from the table below where K is the pipe diameter in Size Inches Sch. 40D feetfPipe Size Inches Sch. 40D feetfPipe Size Inches Sch. 40D feetfPipe Size Inches Sch. 40D feetf 1 1 1 3 4 5 6 12 14 16 18 30 36 42 3 of 5 Friction Losses in Pipe Fittings6/13/01 Loss of Water in Pipe Fittings in Terms of Equivalent Length - Feet of Straight PipeNominal pipe sizeActual inside diameter inches dFriction factor fGate valve - full open90 elbowLong radius 90 or 45 std elbowStd tee - thru flowStd tee - branch flowClose return bendSwing check valve - full openAngle valve - full openGlobe valve - full valveButter- fly valve90 Welding elbowMitre bendr/d = r/d = 45 90 1 1 1.
3 622 .824 .025 .023 .022 ..55 .70 .92 2 2 3 4 .018 .018 .017 . 114 8 10 12 .014 .014 .013 . 125 149 164172 226 284 338 18 20 24 .012 .012 . 113 188 210 235 283 425 478 533 641 113 14036 42 4834 40 .010 . 100 200 230142 167 192 40 4643 50 58170 200 230L/D83016206050 to 6 = 100 24 to 48 =50150340 20121560 Page 4 of 5 Friction Losses in Pipe Fittings6/13/01
