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Pipe Stories

HeatingHelp Administrator Posts: 650
edited October 2022 in THE MAIN WALL
imagePipe Stories

Have you ever wondered how nominal pipe sizes came to be? Read on.

Read the full story here


  • Lance
    Lance Member Posts: 272
    AND to add another comment and a reason maybe Master plumbers lost the sprinkler license authorization is because the flow volume sizes the pipe ID but Fittings size the OD. Sprinkler schedule 10 is larger inside than a schedule 40 pipe. Sprinkler heads and flow is critical, and systems are engineered on flow. And some uneducated pipe fitters would use a schedule 40 in place of a 10 and reduce the capacity of the flow failing the system. I have done all three, hvac, plumbing and fire protection. It's not what you did the last time that works, it what you engineered before you start that works. Oh, and then there were the wood pipes i worked on, and I chose not to learn their engineering.
  • Intplm.
    Intplm. Member Posts: 2,037
    edited October 2022
    I would hazard a guess to think that plumbers identify pipe from the inside diameter ID because that is where the flow takes place and is most important in that respect to the plumbing trade. Where as the hvac trade is not concern as much with the inside diameter but by the OD to differentiate the type of tubing, ie, HVACR?