1/2 valve on 3/4 line, 3/4 valve on a 1-1/2" line, etc. like that... Head loss?

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by hamlet_jones, Oct 23, 2013.

  1. hamlet_jones

    hamlet_jones New Member

    Messages:
    11
    Location:
    Idaho
    Howdy,

    I tried a search, and engineers toolbox .com, but I couldn't find nuthin.

    Is the head loss appreciable for using an undersize valve in a system that's otherwise one size all the way thru?
    Does necking down a little make much difference, or, head loss overall?

    My system is 1100 feet, 1-1/2" line all the way thru, except 1" at the make-up places at the ends. I run
    5-10 gpm depending on where the pressure's at during the cycle.

    If anybody has a link to a chart for pressure drop or head loss for valves,
    I'm all ears.

    Thanks
  2. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,021
    Location:
    Cave Creek, Arizona
    Head loss is a function of pipe size and velocity. Therefore, since you have a very low velocity, the smaller connections at either end are inconsequential. Now, if you were trying to put out a forest fire, it would be a major restriction/factor.
  3. hamlet_jones

    hamlet_jones New Member

    Messages:
    11
    Location:
    Idaho
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