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thing31

diameter of water pipe (too much pressure?)

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On 12/12/2019 at 8:16 AM, thing31 said:

Thank you very much Morakot ! it is very helpful !

 

Sure, I get your point, better to start with a 1 inch.

When you write 'Changes in pressure due to the slope should reflect the thickness class of the pipe 8.5/13 rather than the nominal size.', do you mean I should buy a 13 class on the lower (and flat) part of the land, as there will be more pressure than on the slope (again, the connection with the village pipe will be at the top of the slope), whereas on the slope a 8.5 class should be fine? 

 

By the way do you have a good brand of pipes to recommend? I guess the cheapest ones quality is not great.

 

Use a hdpe pipe. 

 

Go to global house and look at the fittings on the wall is a sample board of the different types/sizes etc. 

 

Burying pvc is asking for trouble in the future... 

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I agree with mogandave--tried to like his post but the forum gave me an error message for it.

My uncle is a civil engineer and I have done literally hundreds of hours of work with him on various kinds of pipe, from steel, to PE (polyethlene), to PVC (very little though, as this is not used for commercial projects)--mostly steel.  One thing I heard him say more than once is that the restriction of flow through a valve had a negligible impact on volume of flow.  One big reason for this is the Venturi effect, where the flow will speed up as it passes through a narrow restriction.

 

The illustration is somewhat accurate, but misleading.  This is because water, like electricity, will take the path of least resistance.  Given three outlets, all at the same time, the water would act much as depicted.  But if the two larger outlets were valved off so that only the smallest nozzle remained, the water would flow in much greater quantity through it.

Regarding the OP's pipe question, I would also recommend the larger diameter pipe, but for a different reason entirely.  The larger pipe will have a greater surface area for the glued joints, which will mean the joints are more likely to hold together without special thrust blocks or pouring them into cement.  The pressure is not so much a concern in terms of the pipe bursting, but rather in terms of the joints not holding together.  In this part of the world, most who work on the pipes will not glue them carefully to begin with, and joints are often the weakest point.  If glued properly, with a sufficient joining pressure that is held for at least 60 seconds before releasing it, there should be greater stability.  

 

One way of avoiding the pressure problems and the joint issues might be to consider getting a roll of HDPE (high-density PE) pipe instead.  It's good stuff, which is why the municipal water suppliers like to use it.  It does have special joining techniques, however, and is not so versatile in home use.

 

If the head on the water (drop in elevation) is sufficient to have over 80 psi of pressure at the bottom (~185 ft./55 m. elevation drop), you might need a pressure-reducing valve.  This is NOT accomplished by passing the water through a small orifice, because the static pressure when water is not in use will still climb to the level calculated by the head.  Furthermore, at high pressures, sudden valve closures may set up water hammer in your pipe and that certainly could cause it to burst.  At high head, therefore, a pressure relief valve may also be warranted.

 

Hope this helps.

 

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Shaemus and AsianatHeart are giving the OP a good tip to consider HDPE pipe. He can also pay a minor extra fee for a larger water meter. It is only a one time fee to have a larger water meter so he has the ability to draw more water from the PWA line serving his property.  HDPE connectors are widely available in Buriram. 

Buriram HDPE Water Pipe Roll Delivery.JPG

Buriram Surin HDPE Water Pipe Connectors.JPG

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Posted (edited)
On 12/12/2019 at 8:16 AM, thing31 said:

When you write 'Changes in pressure due to the slope should reflect the thickness class of the pipe 8.5/13 rather than the nominal size.', do you mean I should buy a 13 class on the lower (and flat) part of the land, as there will be more pressure than on the slope (again, the connection with the village pipe will be at the top of the slope), whereas on the slope a 8.5 class should be fine?

 

Sorry, I just saw your reply now. Whether you need 8.5 or 13 depends on how steep the slope is.

 

For example if water comes in with 3 bar and your house is 55 metres lower than where the water comes in, than 8.5 will NOT be sufficient.  You need to add one bar for each 10 metres vertical drop, plus 5 bar for in coming pressure (spikes). (Try not to mix different thickness classes; it's not very practical.)

 

If the slope is too steep, you can also look into installing pressure reducers at certain points. This might be more cost effective then increasing the thickness.

 

WP says that sunlight can effect the pipes over the years. Yes that's correct. An inexpensive and effective way is to paint them where they are exposed.

 

 

Edited by Morakot

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