Get some hose. Fit a tyre valve at one end and connect the other to the tap. Make sure that the hose is vertical and full of air. Turn on the tap and measure the pressure with tyre pressure gauge.
R
Water hammer occurs when flow is shut down suddenly. The water is not compressible and has inertia. I believe that uPVC pipe has a safety factor of at least 2 to protect against water hammer.
R
Fantastic. I bet Maxie sings that song on the beach in the Far East up the tree in that frock. What a man! Truly fantastic. Such a foot tapping tune as well. Only Maxie can do that.
ok - how long (high) is required for the vertical air-filled bit?
Not sure how to do this?
Ingenuity...
This _is_ a diy group :-)
Yebbut - I wasn't sure if the duct tape would hold...
Domestic mains pressure depends on where you live how many houses it has to serve and how tall the buildings are. Example on a main road in London you would expect the main pressure to be 10 bar or so, but in very remote plac es you should expect low pressure e.g. in the lake district where there is very little housing for miles apart. You Should expect about 3 bar pressure in some remote areas. Most domestic taps and boilers can run off 1 bar pre ssure, but if you had a house three stories high then this would not be eno ugh pressure and your water will come out at a drisel or not at all on the top floor. 10 bar mains pressure is pretty standard now. Just imagine all y our neighbours getting up at 7 in the morning all wanting a shower at the s ame time? That is a large demand on supply! You may even notice that a some parts of the day you have better pressure than other times of the day depe nding on the demand on the supply.
Bravo on waiting 7 years to spout bollocks.
Tim
Quite. Even after they replace Victorian mains in London they don't supply anything like 10 bar - and a good job too given there are still very many iron/lead communication/supply pipes.
And nice pun. Pity we can't apply 10 bar to his bollocks/her t*ts.
This is a common misconception, partially closing a stopcock down has no bearing on the water pressure, all it does is slow the flow rate down, to reduce pressure you need a pressure reducing valve set at the desired pressure on the draw of side.
This very old thread seems to periodically get revitalised. I suspect a lot of people do not understand the difference between flow rate and pressure. You can often see an initial high pressure spurt if you just close down the tap a bit but from what I've been told pressure reducers do not have this pressure build up issue. However thus far despite our pressure being quite high, nothing has been damaged, though you can clearly hear the initial spurt when the washing machine solenoid valve initially opens. Brian
Here in Palm Desert California our home was built with TWO water pressure r egulators. One for the house supply (set at 50psi) and one for the garden s prinkler supply. I have never bothered to determine the latter pressure. St atic pressure from the street is 95psi which varies but not by much. Construction methods here involve a cast concrete slab with the water pipes set in the concrete. To me, this is BLOODY LUNACY as anyone knows concrete flexes and cracks. Slab leaks are not at all uncommon. Guess why?
This being a UK group, we are not particularly interested.
Yes well thinking ahead has never been a strong point of builders anywhere in the world when it affects their bottom line profit. Brian
Turning the stop tap down does not reduce the static pressure - sure it wil l reduce the flow and consequentially the running pressure, but as soon as you stop demand, even with the stop c*ck reduced to a minute pin hole, the standing pressure is exactly the same as the main line pressure - I would h ave thought it to be obvious to an expert
But you don?t have to be an expert to spot that you?re responding to 9 year old post. I think the problem may well have been resolved by now.
Tim
The water companies have a statutory minimum pressure they have to deliver. They should also have a statutory maximum of 4 bars. 4.5 is the rated working limit for many central heating boilers etc. Above that will damage them. A fitting blew off the mains supply in my mothers flat at somewhere between 7 and 11 bars. Three flats uninhabitable for 18 months and £200k insurance bill. No liability to the water company. Partially closing the main supply valve reduces flow, (and make noise) but does nothing to reduce pressure. You need a reducer on the system if it is above 4 bars. The big step down valves on the water mains they install now are not fail safe and have a habit of failing by giving full pressure - 11 bars etc. Not good for your system. The design rating of copper pipe is 12 bars but the fittings etc are your weak point. If your system is going to see over 4 bars it needs to be properly pressure tested and certified to take max pressure + 20%. This countries standards are so bad it makes me weep, (my pipework as well).
Did you miss this ^^^^^^^^^^^ ? Over 9 years ago.
I wonder how many pipes have failed due to high pressure in the 10 years since the post replied to here? Brian
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