Friction of Fittings

Loss of Air Pressure in Hose Caused by Friction
Description of Product Equivalent Length in Pipe Diameters (L/D)
Globe Valves
 Stem Perpen- dicular to Run �–With no obstruction in flat, bevel, or plug-type seat Fully open 340
�–With wing or pin guided disk Fully open 450
Y-Pattern �–(No obstruction in flat, bevel, or plug type seat)    
�–With stem 60 degrees from run of pipe line Fully open 175
�–With stem 45 degrees from run of pipe line Fully open 145
Angle Valves
 �–With no obstruction in flat, bevel, or plug-type seat Fully open 145
�–With wing or pin guided disk Fully open 200
Gate Valves
 Wedge, Disk, Double Disk, or Plug Disk   Fully open 13
  Three-quarters open 35
  One-half open 160
  One-quarter open 900
Pulp Stock   Fully open 17
  Three-quarters open 50
  One-half open 260
  One-quarter open 1,200
Conduit Pipe Line Gate, Ball, and Plug Valves
 Fully open �–3**
Check Valves
 Conventional Swing �–0.5† …. Fully open 135
Clearway Swing �–0.5† …. Fully open 50
Globe Lift or Stop;� �–Stem Perpendicular to Run or Y-Pattern����� 2.0† .… Fully open Same as Globe
Angle Lift or Stop �–2.0† .… Fully open Same as Angle
In-Line Ball �–2.5 vertical and 0.25 horizontal† .… Fully open 150
Foot Valves with Strainer
 �–With poppet lift-type disk������������������������ 0.3† …. Fully open 420
�–With leather-hinged disk������������������������� 0.4† …. Fully open 75
Butterfly Valves (8-inch and larger)
 Fully open �–40
Cocks
 Straight-Through �–Rectangular plug port are equal to    
�–100% of pipe area Fully open 18
Three-Way �–Rectangular plug port are equal to Flow straight through 44
�–80% of pipe area (fully open) Flow through branch 140
Fittings
 90-Degree Standard Elbow   30
�–45-Degree Standard Elbow   16
�–90-Degree Long Radius Elbow   20
�–90-Degree Street Elbow   50
�–45-Degree Street Elbow   26
�–Square Corner Elbow   57
Standard Tee �–With flow through run   20
�–With flow through branch   60
�–Close Pattern Return Bend   50
  ** Exact equivalent length is� † Minimum calculated pressure
  equal to the length between� drop (psi) across valve to provide sufficient flow to lift disk fully.
  flange faces or welding ends