change to 22mm pipe from mains?

[SQUIRMSTER]

I live in a maisonette and there is a single pipe that comes in from the street for both flats.

The pipe that enters the building is lead, probably 3/4, and is changed to 15mm copper pipe with an stopcock. This goes on for about 5-10m where it splits to both flats.

Generally, water pressue is ok, but when more than one tap is on, pressure drops significantly.

My question is, if the 15mm pipe was changed to 22, would that help to increase pressure, or would I not really notice a difference? or would it be better if the pipes were split at the point of entry instead of about 5-10m in as currently?

Thanks

 

[Roy_66]

Try the following ready reckoner:

Flow Rate Calculator - Pressure and Diameter | Copely - https://www.copely.com/tools/flow-rate-calculator/

From that I reckon the single 22mm wins over a pair of 15mm by about 50% for the lengths you suggest.

I've assumed 1 bar mains pressure ( min acceptable domestic pressure ? )

There are other calculators and the formula avail, so best do a cross check. Google "flow formula for pipe".

Cheers,

Roy (A very amateur plumber)
[automerge]1591369116[/automerge]

Try the following ready reckoner:

Flow Rate Calculator - Pressure and Diameter | Copely - https://www.copely.com/tools/flow-rate-calculator/

From that I reckon the single 22mm wins over a pair of 15mm by about 50% for the lengths you suggest.

I've assumed 1 bar mains pressure ( min acceptable domestic pressure ? )

There are other calculators and the formula avail, so best do a cross check. Google "flow formula for pipe".

Cheers,

Roy (A very amateur plumber)

P.S. I should also have said, best to use the above on a big screen comouter/tablet. Mobile works but allmresults numbers will be vertical so bit tricky to read.

 

[Chuck]

The pipe that enters the building is lead, probably 3/4, and is changed to 15mm copper pipe with an stopcock. This goes on for about 5-10m where it splits to both flats.

Hmm. Lead pipe has quite thick walls. IIRC, 1/2" ID lead (5lb/yd) has an OD of slightly over 3/4". If I'm right, increasing the size of you current 15mm copper tube is not likely to make a significant difference because the flow will still be limited by the lead supply pipe.

You might want to get a couple of quotes for replacing the supply pipe and increasing its diameter at the same time.