Long run, village supply 1/2"!

[nlimcm]

Hello,
I'm struggling to decide what size pipe to use - and any plumbing advice would be greatly appreciated!

We have village water which comes in on 1/2 pipe -this is our only access and we have a 1/2 inch meter. The house will be approx 120m away, and we will probably have a tank and pump for the house supply.

My current question is what size pipe should I use? I've read lots about pressure and flow, and I understand bigger pipe equals less pressure loss over a distance (http://www.druckverlust.de/Online-Rechner/dp.php). But where our supply is small, what impact does this have? I'm also unsure what the village water supply pressure is to start with.

So, should I use a bigger pipe after the 1/2" meter?
Or make a concrete ring tank and then use a bigger pipe from there?

Right now we need to water trees etc and provide water for the build.

Many thanks
Natalie

[Klondyke]

You cannot rely on a steady water pressure from the poor village system, especially when fed by 1/2" pipe.

You surely will need a storage tank at your house with a ball valve that shut off prior overflow (usually included in the plastic tank 1,000 - 2,000 L bought at GH or Thai Wasadu). From there on an automatic pressure pump keeping the pressure in the house water system.

[mikenot]

You will not gain any pressure by installing bigger pipe, so settle for the 1/2 inch and just let your tank fill gradually, with a pump to supply pressure into the house. Use the money you save by buying 1/2 inch pipe to get a better grade PVC !

[Sometimewoodworker]

You will not gain any pressure by installing bigger pipe, so settle for the 1/2 inch and just let your tank fill gradually, with a pump to supply pressure into the house. Use the money you save by buying 1/2 inch pipe to get a better grade PVC !

While you will not gain pressure gain by installing a bigger pipe you will certainly loose much less.
I have chosen to use 32 mm ppr throughout our system and though it's a little bit more than double the price of ½ inch as a relative cost it is insignificant.


http://www.calculatoredge.com/mech/pipe%20friction.htm

¾ inch

1 inch

½ inch

[nlimcm]

Thanks for the responses.

Can anyone confirm what happens if I just go from the current 1/2" supply to 1" pipe across the land?
If not I will go with 1/2" pipe from the meter to a tank near the gate, then 1" pipe across the land to where the house will be.

Thanks

[Sometimewoodworker]

Thanks for the responses.

Can anyone confirm what happens if I just go from the current 1/2" supply to 1" pipe across the land?
If not I will go with 1/2" pipe from the meter to a tank near the gate, then 1" pipe across the land to where the house will be.

Thanks

That is easy.

You will have vastly lowered friction losses in that pipe. For very low flow rates it may not be a big gain

[Klondyke]

One of the examples of inverted practice in Thailand: In many cases the investment is oversized (e.g. building structures), in many cases it's undersized (always water system).

Even the logic: I was once persuaded that the 1/2" is better, resulting in a higher pressure.

[nlimcm]

Thanks - a tank and 1"pipe it is then!