Water Pipes

[mobile69]

Our house is under construction. THe builder plans to install half inch pipes from groundfloor level up to each bathroom upstairs - seperate pipe for each bathroom. I thought this was too small, leading to too low pressure, say after flushing loo, in shower. Now he says he'll put 1 inch pipe to bathrooms, with half inch to taps etc. The plan is to have our own watertower (we're in middle of nowhere, no mains). What diameter pipe sholud we have from tank atop tower to house, about 25m horizontal distance, and is one inch pipe going to be too big to have feeding the bathrooms. I don't pretend to have any knowledge of plumbing, only the poor standard in houses I've rented. Any helpful advice welcomed.

[jayenram]

The larger the pipe diameter, the less pressure drop. I would go for 1" diameter until you reach the outlets. The difference in cost is insignificant.

[Jai Dee]

The larger the pipe diameter, the less pressure drop. I would go for 1" diameter until you reach the outlets. The difference in cost is insignificant.

That's exactly what we've just installed in our new house.

[astral]

Remember a 1" pipe can feed 4 x 0.5" pipes with no loss of pressure.

It all depends on how many taps you think will be open at the same time.

Filling the toilet tank corresponds to one tap.

[RamdomChances]

Actualy the smaller the dia pipe the higher the pressure, your confusing "flow rates" with pressure, as astral says 1, 1 inch pipe can supply 4 half inch ones as the cross sectional area is the same ( ok you will lose a little bit due to friction ect )

Anyway the best is probably run a one inch main, and drop down to half inch for the outlets. Obviously if you only have a one inch main into the house its not going to make that much difference unless you have a pressure pump.

[GuestHouse]

Yep, I agree but I would also make the main run to the house from the tower as large as practicaly possible.

Then as others have said, inch feeders to each of the bathrooms/toilets/kitchens with half inch to each tap/shower etc.

Here's another thing.

Keep a close eye on how the joint the pipes, sloppy workmanship while jointing will create problems of leaks later. Leaks behind finnished walls or in finnished floors are expensive!!!

Here's how I joint the plastic pipes.

Your plumber should cut the pipe square (no slanting angles).

Then he should remove all the burrs from inside and outside the cut edges (Fine abrasive paper should be used)

Now he should slightly abrase the inside of the coupling with very fine abrasive paper.

Do the same to the pipe where the joint is going to be made (abrase all around the pipe and for a bout two inches from the cut end).

Make sure the mating surfaces are spotlessly clean and absolutely dry before applying a coat of the jointing compound to the 'whole' of the pipe jointing area (All around the pipe for a good inch and a half from the cut end).

Now push the cut end of the pipe into the fitting as far as you can force it and before the glue sets sets give the pipe and fitting a single twist through about a quater turn - this ensures the joint is fully made around all the jointing surface.

I support all joints against a solid surface, perhaps tieing them to a support or when burried in the ground I put them in a close fitting concrete channel (U shaped).

Make sure that the whole system is pressure tested with water before back filling any trenches or plastering over any joints.

I useually tie a piece of tissue paper around each joint and leave the pipework under pressure for a few hours then go check all the tissues are still dry.

Wath out too for stressed joints. ie Somchai the plumber is three inches short of pipe, so he pulls the ends of the two pipes together to make them close enought to join - They will then be under constant stress and will eventually break at the joint.

[mobile69]

Thanks, chaps, for the replies. The builder has already agreed to go for 1" to each bathroom & half inch then to the outlets. THis sounded reasonble to me, but having no experience of plumbing, I was concerned he was doing it just to keep me off his back, even tho' it may have been less practical.

As for the water tower tank to house, I haven't looked into this yet, but what outlet sizes are standard on the tanks. Seems pointless specifiying a large diameter pipe if the outlet hole is only 1"...

Also, how high should the tank outlet be above shower taps height for good pressure. There is a limit to how high the solar heated water tank can be, but if the pressure on this supply is too low, I can always add a pump.

[phuketsiam]

Standard is 6 feet (2 meters) or more between the water tank and the shower head, but if you like a bit pressure then go for more

[chownah]

I pretty much agree with Guesthouse about glueing pipe....except I have found no need to sand the outside of the pipe or the inside of the fitting.....if they are clean and dry I just put a light coat inside the fitting (being sure it is wetted all the way around everywhere) and a liberal coat to the pipe (again being sure it is wetted all the way around everywhere) and jam them together (no need to turn but sometimes I do anyway). I've glued alot of pipe and NEVER had a leaker.

[LoveDaBlues]

Thanks, chaps, for the replies. The builder has already agreed to go for 1" to each bathroom & half inch then to the outlets. THis sounded reasonble to me, but having no experience of plumbing, I was concerned he was doing it just to keep me off his back, even tho' it may have been less practical.

As for the water tower tank to house, I haven't looked into this yet, but what outlet sizes are standard on the tanks. Seems pointless specifiying a large diameter pipe if the outlet hole is only 1"...

Also, how high should the tank outlet be above shower taps height for good pressure. There is a limit to how high the solar heated water tank can be, but if the pressure on this supply is too low, I can always add a pump.

I'm curious as to why there is a limit on the height of the water tank. Some sort of law? In downtown Udon I've seen a guy with a tank about 12-15 feet high (ground-level to bottom of tank).

[mobile69]

There is a limit to how high the solar heated water tank can be, but if the pressure on this supply is too low, I can always add a pump.

I'm curious as to why there is a limit on the height of the water tank. Some sort of law? In downtown Udon I've seen a guy with a tank about 12-15 feet high (ground-level to bottom of tank).

The solar water tank will be on the roof, so it's height will be limited by the height of the house....

[backflip]

Something else to consider...be sure that the pipe wall is as thick as possible. In the US, most people installing underground irrigation use "schedule 40" PVC pipe - VERY robust. I've had to redo a buried irrigation system that used (non-schedule 40) PVC pipe that was as thin (and as fragile) as eggshells. What a pain in the butt to replace!

[TBWG]

Our house is under construction. THe builder plans to install half inch pipes from groundfloor level up to each bathroom upstairs - seperate pipe for each bathroom. I thought this was too small, leading to too low pressure, say after flushing loo, in shower. Now he says he'll put 1 inch pipe to bathrooms, with half inch to taps etc. The plan is to have our own watertower (we're in middle of nowhere, no mains). What diameter pipe sholud we have from tank atop tower to house, about 25m horizontal distance, and is one inch pipe going to be too big to have feeding the bathrooms. I don't pretend to have any knowledge of plumbing, only the poor standard in houses I've rented. Any helpful advice welcomed.

Hi mobile 69

1" pipes sounds ideal but bear in mind if you are using hot water heaters for the showers they have a very small diameter pipe inside them which obviously restricts the flow. I suppose it is possible to buy commercial type heaters which have larger bore pipes.

I use the normal heaters to supply hot water to a bath, flow is pathetic need to plan months ahead should I want a full hot bath!!

Consequently don't stand down wind of me!!!

TBWG