water main pipe sizing

[johnacky]

Hi all, after some advice, ref a single rising water main in apartment block of five flats. It has a 25mm water main entering propery, whicy feeds two ground floor flats. the three further flats are fed off 15mm, that comes off the single 25mm riser. The incoming water pressure is 2.2 bar, and 2 bar by the time it reaches top flat, with 14lm flow rate. Just wondering if this sounds correct.

 

[Agile]

It sounds very likely.

Not very good though. The top flat will seriously lose pressure and flow when lower flats are using water! May stop completely!

You don't explain your interest so its difficult for me to advise you.

A new 25 mm from inlet to each flat would be far better!

Then an upgrade the incoming pipe size.

 

[johnacky]

I have looked over a job , that is in dispute over pipe size by developer and architect. Developer wanted larger supply pipe, architect adament that 25mm supply was sufficient. I have been asked to look over job, as architect has stated that had the 25mm been fitted to each flat then water pressure would have been significantly improved over the 15mm. As far as i can see flow rates are over 9lm at every tap, and water pressure is over 1 bar even with taps running in every flat simultaneously. Am i wrong in thinking water pressure would not.be improved significantly unless incoming water main had been increased. Cheers for advice

 

[Porque223]

Using calculators on the Engineering Toolbox site you can probably quantify the improvement but there are also homeowners' perceptions and maybe it is good practice to allow some headroom in case the effective pipe ID decreases over time.

 

[Graham3232]

Are these new flats? If its all off one supply, does the Landlord pay the bill? The last flats I worked on we had the water company put in a new supply and meters for each flat as is the norm these days. Did the architect mean 25mm to each flat? Small blocks like this normally have a 32mm pipe from my experience

 

[Agile]

I have been asked to look over job, as architect has stated that had the 25mm been fitted to each flat then water pressure would have been significantly improved over the 15mm.

In what capacity have you been asked to look over it?

It sounds like a lack of communication. I expect the architect wanted an individual 25 mm to each flat. But the developer only put in a single pipe supplying all the flats!

Its not the arrangement the water supplier would want either!

9 li/min is the minimum flow rate. I rather doubt that it is a dynamic flow rate at 1 bar.

Tony

 

[Porque223]

This
http://www.google.com/search?client...778,d.dmQ&fp=e1c2c23f5b7f4a79&biw=962&bih=800
might address both flow rate and pressure.