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Minimum Static Pressure

Discussion in 'Irrigation' started by bicmudpuppy, Oct 13, 2006.

  1. bicmudpuppy

    bicmudpuppy LawnSite Silver Member
    Messages: 2,781

    Ok, this is going to sound like a lazy question, because it is. Anyone know if uniform code lists a minimum static pressure for potable water in municipalities? Here in the KC area, my most common problem is high pressure. I had the guage pop to over 135psi the other day. I have a neighborhood with 3-6 year old WORKING systems (well until this summer) that are now running less than 10gpm through 5/8 meters. I have static daytime pressures of less than 35psi. I seem to remember when I was in DFW being told that one of the areas there that had pressures this low were being fined by the fire marshal because they were not providing adequate pressure to the fire hydrants with pressures less than 40psi. I was told that if the working pressure drops below 20psi, you can shell a pumper. It is possible for those cloth hoses to collapse and be sucked up into the pump.........I don't know if that is true, but while discussing low pressures that was what I was told back then.
  2. PurpHaze

    PurpHaze LawnSite Fanatic
    Messages: 5,496

    Don't know how accurate this is but I attended a seminar a few years back where pressure loss (as more building occurred and no additional water sources were provided to a city) was one of the topics. It was stated that the minimum PSI a city was responsible for providing was somewhere around 16-18 PSI... strictly for the amount a fire hydrant needed to supply a pumper which in turn boosts the pressure for the fire fighting equipment. The "Polyanna" was that as water became more scarce by many users tapping into a limited source it would be up to the individual users to boost their own pressure.
  3. gusbuster

    gusbuster LawnSite Bronze Member
    Messages: 1,926

    Actually, In Ca(well at least in the Bay Area), the static pressure minimum is 25 psi and 3 gal\minute water flow. I know the Counties of Alameda, San Mateo, Santa Clara, San Francisco, Marin, Salono and Napa Counties enforce this rule.

    During the Loma Prieta earthquake(San Francisco Marina fires) and the Oakland hills fire, part of the problems was that there wasn't water available because of lack of water flow.

    Now an earthquake you really can't do anything about it because of broken pipes. But with a wild-land fire, when you have residents and fire trucks all pulling from the same source, your not going to have flow, even with 3" and 4" mains that they use. Besides poor communications and narrow roads, during the Oakland hills fire, part of the reason so many homes were lost was the simple fact that the old water systems couldn't handle the draw of water.
  4. cush

    cush LawnSite Senior Member
    Messages: 352

    I'll keep flushing so CA get enough water.:laugh: :laugh: :laugh: :laugh:
  5. gusbuster

    gusbuster LawnSite Bronze Member
    Messages: 1,926

    Wouldn't affect me and purp, our water is fresh mountain snow water, not water from the snake.
  6. PurpHaze

    PurpHaze LawnSite Fanatic
    Messages: 5,496

    He's flushing it downstream to the Oregonians and Washingtonians via the Snake/Columbia confluence. :laugh:

    One of my brothers lives in Pasco so I'll give him a heads-up. :)

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