Plumbing – the Pressure Number (PN) of Shedule 40 and Schedule 80 PVC Pipe

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Does anybody know the pressure number (PN) of schedule 40 and schedule 80 PVC pipe commonly sold in the United States and Canada?

The PVC in my part of the world is classified by PN number, and I'd like to know which PN number is ideal for DWV applications.

I'm interested in finding out the pressure number that is equivalent to schedule 40 PVC. We'll be using 5 cm, 8 cm, 11 cm and 16 cm diameter pipes for DWV applications. Also, our climate is subtropical (i.e. warm) and the temperature does not go below freezing.

Best Answer

Schedule 40 PVC has a pressure rating of 120 psi to 810 psi, depending on pipe size, and temperature.

At 73°F the pressures are as follows:

  • 2" = 280 psi
  • 3" = 260 psi
  • 4" = 220 psi
  • 6" = 180 psi

Then as the temperature increases, you'll derate the values as such:

  • 80°F - 88%
  • 90°F - 75%
  • 100°F - 62%
  • 110°F - 51%
  • 120°F - 40%
  • 130°F - 31%
  • 140°F - 22%

-Source

Schedule 80 PVC has a pressure rating of 210 psi to 1230 psi, depending on pipe size, and temperature.

At 73°F the pressures are as follows:

  • 2" = 400 psi
  • 3" = 370 psi
  • 4" = 320 psi
  • 6" = 280 psi

Then as the temperature increases, you'll derate the values as listed above.

-Source

Pressure depends on temperature, size, and schedule.

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