Schedule 40 & Schedule 80 Pipe

Before you begin!
For steam system to work properly, it is important to maintain reasonable velocities of liquid passing through piping. Velocity is constant for a given flow rate and independent of pipe length. Pipe diameters are selected to achieve a velocity of 5-10 feet per second. Chart versions of the data used to build this calculator are also available. Schedule 40 or Schedule 80

Pipe Schedule and Size

Schedule refers to strength of pipe. Wall thickness of pipe varies based on dimensions of pipe as defined in ASME standard 36.10.

Pipe Outer Diamater (OD)
Pipe Inner Diamater (ID)
Wall thickness

Velocity and Friction Loss

Velocity and Friction Loss are derived from the the nominal pipe size chosen from Pipe Schedule and Size and pump flow rate.

gallons ⁄ min (GPM)
feet ⁄ second
Friction Loss
psi ⁄ 100 feet
  • Velocity is over 2.75 feet/second. This is normal for saturated water or on a deaerator.
  • Velocity is over 5 feet/second. This is for typical applications or cold water suction.
  • Velocity is 7-12 feet/second. This is normal for transfer piping on a deaerator.