House Water tank Pipe

[transam]

1 minute ago, norbra said:

You can't read? I mentioned earlier that the water in the bins had not been used for more than 10 years to my knowledge. She decided this course of action whilst I was in Australia getting long term medical treatment 

I am sorry to hear she removed your cash outlay for improvements when you were away..........

[nigelforbes]

3 minutes ago, lopburi3 said:

I did read it and that is why I posted.  Use normal water for daily use but have additional supply for outage seemed to be your goal and that was what I posted.  Without a pump you are not going to have any usable water pressure to any house taps from a ground level tank so KISS principle seems to be best option.

A pump will be installed although not straight away. The design attempts to accomodate an emergency water supply via the tank in the short term but also be capable of accepting a pump later. 

 

I accept there will be very little pressure from a ground level tank without a pump  although there should be enough to fill a toilet cistern, a washing machine and wash hands via a basin. The water outages are not protracted but they seem to be frequent. The water tanks typically measure two meters high, a toilet cistern water inlet is at under one meter, the connection to the washing machine is also under one meter. That means there should be half the water in the tank available for emergency use, 500 liters, that should be more than enough to get them through temporary outages, for a limited period of time.

 

Yes, we could just instal a tap at the bottom of the tank and string a hosepipe around the place and use clay pots but we're trying to get away from that. And anyway, that configuration would need to be adapted when the pump is installed, hence, I'm trying to accommodate both scenarios and still move forward, not backwards 

[nigelforbes]

9 minutes ago, transam said:

I am sorry to hear she removed your cash outlay for improvements when you were away..........

 

13 minutes ago, norbra said:

You can't read? I mentioned earlier that the water in the bins had not been used for more than 10 years to my knowledge. She decided this course of action whilst I was in Australia getting long term medical treatment as the pump had failed.

Get a room please, I'm trying to sort out my plumbing. Ta!

[norbra]

9 minutes ago, transam said:

I am sorry to hear she removed your cash outlay for improvements when you were away..........

If that's not trolling I surrender

[transam]

1 minute ago, nigelforbes said:

 

Get a room please, I'm trying to sort out my plumbing. Ta!

Your plumbing is sorted, the fix info is in abundance, another's isn't.........................????

[sometimewoodworker]

1 hour ago, lopburi3 said:

I did read it and that is why I posted.  Use normal water for daily use but have additional supply for outage seemed to be your goal and that was what I posted.  Without a pump you are not going to have any usable water pressure to any house taps from a ground level tank so KISS principle seems to be best option.

While you are absolutely correct that you won’t have usable water pressures from the ground level tank, it is reasonably easy to allow city water pressure to fill and by pass the tank so you have water pressure when the city supply is working, pumped pressure when the city supply is cut and a trickle downstairs when both water and power is cut

 

Of this I am totally sure as we have that, though we still have water at all outlets as our ready use tank is at high level

[bang saen guy]

18 hours ago, nigelforbes said:

I think I'm as per the schematic I posted earlier, half inch to the tank, half inch along the mains bi-pass and three quarter inch from tank to house base (via a pump later) and half inch in to individual outlets.

 

Remember, the primary purpose is to provide a supply when the City supply stops. Remember also, that concurrent usage of outlets is absolutely minimal and that existing pressure from City supply is very good.

 

What problems does anyone see?

Normally the discharge piping needs to be smaller than the suction piping

[nigelforbes]

3 hours ago, bang saen guy said:

Normally the discharge piping needs to be smaller than the suction piping

Thanks for this, you're right, well spotted.

[sometimewoodworker]

3 hours ago, VocalNeal said:

Someone mentioned friction loss. In a domestic system when the toilet cistern is filling. Really???? The filters on the faucets/taps will cause more lose.

I did, there is. You are using faulty logic, just because the filters and outlets cause a pressure/flow drop doesn’t mean that you should allow small pipe to cause another drop.

 

3 hours ago, VocalNeal said:

Most bathroom fittings are 1/2 BSP or NPT so running any bigger than 1/2 pipe to those locations is meaningless. Unless there is a reason for extra rigidity in the piping system. The best advice in the thread is use the same pipe size as the pump. K.I.S.S.

This advice, while wrong, will work well as long as you have a high pressure supply. This is why the U.K. plumbing is generally ½” because the water pressure is consistent and quite high compared to Thailand.

 

Regrettably Thailand has generally low water pressure that is often inconsistent along with a power supply that is equally flaky. Both of these mean that if you live in areas that suffer these problems the advice to simply use ½” pipe for everything is not good as you are likely to have virtually no water at times.

 

[sometimewoodworker]

4 hours ago, bang saen guy said:

Normally the discharge piping needs to be smaller than the suction piping

Where do you get that information?
 

All the pumps I have both inlet and outlet pipes are the same diameter. While some, or many, people will use a smaller outlet there is no requirement in any literature that I have seen.

 

[nigelforbes]

19 minutes ago, sometimewoodworker said:

Where do you get that information?
 

All the pumps I have both inlet and outlet pipes are the same diameter. While some, or many, people will use a smaller outlet there is no requirement in any literature that I have seen.

 

I see quite a few references on the internet stating that the discharge piping should be smaller than the suction piping but nothing from a source I would consider authoritative. If I understand the issue correctly, the purpose is to avoid cavitation.

 

https://www.modopump.net/news/pump-34593302.html

[VocalNeal]

36 minutes ago, sometimewoodworker said:

You are using faulty logic,

No. Process engineering. You know???? Flow in pipes that sort of thing.

[VocalNeal]

33 minutes ago, sometimewoodworker said:

This advice, while wrong,

Are you saying that stop valves behind bathroom sinks are bigger than 1/2"???? Not logic. Observation.

[Encid]

4 hours ago, bang saen guy said:

Normally the discharge piping needs to be smaller than the suction piping

With any single phase (liquid) piping system the aims are to try to keep the suction piping as large as possible and as short as possible and to reduce in size only to meet the pump's suction nozzle size at the nozzle. Reduction in size should be made by use of eccentric reducers (not concentric) which are flat on top. The suction pipe should be as straight as possible and between 5 to 10 pipe diameters in length. This reduces the possibility of cavitation and ensures that the inlet pressure drop is minimal. Keeping the pump suction piping short ensures that the inlet pressure drop is as low as possible. The straight-run pipe gives the system a uniform velocity across the pipe diameter at the pump inlet. Both are important to achieving optimal suction.

 

Pipe sizing is a balancing act between cost and friction loss. Larger pipes cost more, whereas smaller pipes impose greater friction losses on the system. In terms of diameter, discharge pipe diameter should normally match the discharge nozzle or flange on the pump, but can be larger to reduce friction losses and decrease system pressure. Pump discharge piping should never be reduced in size less than the discharge nozzle except for offtakes to consumer outlets (showers, faucets etc.) because it puts unnecessary back-pressure on the pump and can greatly reduce pump life and performance.

 

[nigelforbes]

5 minutes ago, Encid said:

With any single phase (liquid) piping system the aims are to try to keep the suction piping as large as possible and as short as possible and to reduce in size only to meet the pump's suction nozzle size at the nozzle. Reduction in size should be made by use of eccentric reducers (not concentric) which are flat on top. The suction pipe should be as straight as possible and between 5 to 10 pipe diameters in length. This reduces the possibility of cavitation and ensures that the inlet pressure drop is minimal. Keeping the pump suction piping short ensures that the inlet pressure drop is as low as possible. The straight-run pipe gives the system a uniform velocity across the pipe diameter at the pump inlet. Both are important to achieving optimal suction.

 

Pipe sizing is a balancing act between cost and friction loss. Larger pipes cost more, whereas smaller pipes impose greater friction losses on the system. In terms of diameter, discharge pipe diameter should normally match the discharge nozzle or flange on the pump, but can be larger to reduce friction losses and decrease system pressure. Pump discharge piping should never be reduced in size less than the discharge nozzle except for offtakes to consumer outlets (showers, faucets etc.) because it puts unnecessary back-pressure on the pump and can greatly reduce pump life and performance.

 

I just read that on the internet, you should have put it in quotes and supplied the link address, the link is here: https://blog.craneengineering.net/6-basic-rules-of-centrifugal-pump-piping

[Encid]

Just now, nigelforbes said:

I just read that on the internet, you should have put it in quotes and supplied the link address, the link is here: https://blog.craneengineering.net/6-basic-rules-of-centrifugal-pump-piping

I did plagiarize that somewhat... but added embellishment here and there to explain further... 

[nigelforbes]

1 minute ago, Encid said:

I did plagiarize that somewhat... but added embellishment here and there to explain further... 

I did notice the additional comma!

[sometimewoodworker]

1 hour ago, nigelforbes said:

If I understand the issue correctly, the purpose is to avoid cavitation.

A reasonable large percentage of Thai pumps are not pulling from a low source, rather the supply is usually under pressure (however slight) this means that cavitation is unlikely to present 

[sometimewoodworker]

1 hour ago, nigelforbes said:

I just read that on the internet, you should have put it in quotes and supplied the link address, the link is here: https://blog.craneengineering.net/6-basic-rules-of-centrifugal-pump-piping

That doesn’t invalidate the statements

[sometimewoodworker]

1 hour ago, VocalNeal said:

Are you saying that stop valves behind bathroom sinks are bigger than 1/2"???? Not logic. Observation.

Not at all. The advice that is wrong is that because stop valves and outlets are ½” the pipes feeding them should be ½”

 

You have a pressure reduction from the outlets and stop valves. You just increase the losses by using ½” pipe.

 

If you have constant high water pressure the friction losses from the small pipes are irrelevant.

since this is not true for the majority of households, reducing friction losses are of significant benefit.

[sometimewoodworker]

11 hours ago, nigelforbes said:

Here's the final schematic, in case anyone things they can meaningfully improve on things.

 

You have decided to allow a higher degree of friction losses in the pipe where it will make the most difference. ¾” is better than ½” but 1” is significantly better than ¾”

[nigelforbes]

41 minutes ago, sometimewoodworker said:

You have decided to allow a higher degree of friction losses in the pipe where it will make the most difference. ¾” is better than ½” but 1” is significantly better than ¾”

I think so. The house has been using half inch pipe for several years, an improvement is in order but where to draw the line, three quarters seems like a reasonable compromise of cost vs performance. I note your comment regarding one inch.

[lopburi3]

55 minutes ago, nigelforbes said:

I think so. The house has been using half inch pipe for several years, an improvement is in order but where to draw the line, three quarters seems like a reasonable compromise of cost vs performance. I note your comment regarding one inch.

But then again if replacing pipe in any case perhaps the cost difference would not be that much?  I used 3/4 when replaced pipes but also have pump suppling 3.5 to 4 bar pressure - expect at normal lower pressures here 1 inch would have been a much better choice (although probably not find many Thai using).

[nigelforbes]

13 minutes ago, lopburi3 said:

But then again if replacing pipe in any case perhaps the cost difference would not be that much?  I used 3/4 when replaced pipes but also have pump suppling 3.5 to 4 bar pressure - expect at normal lower pressures here 1 inch would have been a much better choice (although probably not find many Thai using).

I have to say that if it was my house and my project, I'd opt for the 1 inch pipe in a flash, but the dynamics of this project are a bit odd, to say the least! At Global House today, 3/4  inch blue pipe was 35 baht, 1 inch was 70, "the committee" may not sanction the budget overspend....:) Also, it seems MiL was asked by the village head, at the time the City water supply was installed, to please use 1/2 inch pipe. Why this was is not clear to me, I imagine it might be an attempt to balance demand in some way. I'll see what I can do to push the upgrade through. ???? 

[sometimewoodworker]

8 hours ago, nigelforbes said:

I have to say that if it was my house and my project, I'd opt for the 1 inch pipe in a flash, but the dynamics of this project are a bit odd, to say the least! At Global House today, 3/4  inch blue pipe was 35 baht, 1 inch was 70, "the committee" may not sanction the budget overspend....:) Also, it seems MiL was asked by the village head, at the time the City water supply was installed, to please use 1/2 inch pipe. Why this was is not clear to me, I imagine it might be an attempt to balance demand in some way. I'll see what I can do to push the upgrade through. ???? 

The use of I/2 inch pipe will have given a large loss

 

going to 1 inch as you can see is 5 times better than 3/4 which is 4 times better than 1/2 , 1 1/4 is almost 70x better than 1/2 inch

1/2 to 3/4 = 4.08 reduction in losses

1/2 to 1 inch = 20.8 reduction in losses

1/2 to 1 1/4 inch = 69.3 reduction in losses

 

this-is why we used 32mm pipe

[sometimewoodworker]

10 hours ago, nigelforbes said:

I think so. The house has been using half inch pipe for several years, an improvement is in order but where to draw the line, three quarters seems like a reasonable compromise of cost vs performance. I note your comment regarding one inch.

The cost performance drops off after 1 1/4 inch pipe. Three quarters like most compromises is better but not by that much

[nigelforbes]

10 minutes ago, sometimewoodworker said:

The cost performance drops off after 1 1/4 inch pipe. Three quarters like most compromises is better but not by that much

I suspect MiL is going to be four times better off albeit she won't understand the how or why, the shiny new tank will get all the credit I suspect....which is just fine, as long as she's happy. I'll see if I can sneak in the one inch and will let you know what happened.

[lopburi3]

Another thing to take into account is make sure joints are glued properly - as you intend to install a pump later that pressure will likely be more than source and you don't want to have to re-do plumbing again at that time.  Many here have a tendency to guess on pipe length and then only half install joints when a bit short.