hot and cold water for bath, basin, shower and cistern

[Jupiter01]

I am planning on a bathroom project and was wondering if there is a best practice when it comes to the hot and cold pipes. Can I tee off a pipe run for each service or should I have a "trunk" pipe that I tee off for each service?

I will install isolation valves in each case.

 

[Jupiter01]

to add: I have a combi system with 15mm pipes.

 

[Madrab]

As long as you have suitable pressure then just install a run and then tee off to each appliance.

 

[Jupiter01]

Thanks. I have never felt the pressure is low but I suspect that I need to be more scientific than that?
I am happy to plumb in a way that provides the best level of pressure. What do you suggest please?

 

[SFK]

Jupiter
As I do have low presure, and I felt that I use shower the most, and so was the most critical for me, I kept the pipes to shower as straight as possible, and put in Ts to the other appliances.
Of course I have no evidence that this made any difference, but it satisfied my gut feel.
SFK

 

[Madrab]

When it comes to outlets in the same room, then you look at diversity and dynamic pressure. In other words you won't be using all the appliances in the same room at the same time.

So if you want to avoid impact if say you flushed the toilet and then want to brush your teeth while the toilet fills then break up those supplies but ultimately are you liable to exceed the throughput of the 15mm pipe with more than one outlet open at the same time, that is decided by how good the dynamic pressure is.

Try this test, find a room with more than one outlet, run one as full open as you can then open the other one, is there a noticeable drop in supply at either outlet? Or get a wet test gauge and do a proper dynamic pressure test