|Posted by Philip Mathew on May 01, 2004 at 19:25:04:|
|In response to Re: Whole house water pressure|
: : A plumber recently told me our water pressure from the street is too high at 81 psi. He attached a valve to an outside faucet to measure it--I saw the reading myself.
: : We just moved into this house, so we don't know the plumbing history. How do I know this guy is not just trying to rip us off?
: : If it is too high, how do we fix it?
: : thanks.
: I'm from New York and to answer it from NYC stand point I would figure the following.
: Flow rate would depend on the fixture Units (FU) needed. A FU is based on 7.48 gallons. A Flushometer would require much more GPM's than a tank and bowl.
: You would also have to size this piping besides the GPM required BUT you must take velocity into consideration as you certainly do not want to cause a premature piping failure due to erosion (normally no more than 8 FPS) as this could also cause hydraulic shock (water hammer) and noisy system. (You may want to contact the Copper Development Association for their recommendations.)
: Never ASS U, ME as you make an ass of you and me.
: ASSUME NOTHING plumbing is a science and each system should be designed. This is not a one size fits all. You can design a system by figuring that only 75% of this system would be used at one and base your piping sizes to this factor.
: I hate a one pressure fits all mentality as folks running for examaple a hydronic heating line would certainly not want to have a velocity in excess of 3 FPS with any water temperature AT 180 degrees or higher.
: There are so many factors in plunbing and too many folks rather guess or use a very wide pressure range then doing the actual hoework required to being a "professional plumber"
: Your plumber sounds like he is right on the money
: Saying 40 -60 PSI is "average" sure leaves a lot to be desired when installing a piping system sight unseen.
: Is this a ranch or a multi story dwelling?
: Are there water meters that add a lot of friction loss. What size main. many one family homes I work in have an 11/2 Brass main YET I would never say 1"-2" is normal as some folks do have a fire suppression system (NFPA 13) taken off the water main
: What kind of materials are used for the piping.
: See it is not al that simple UNLESS your following
: Not all "codes" are good for civilized countries BUT pay offs have been known to have been made and inspectors can be bought so good luck.
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