Mains riser, pipe specs, help?

[Matthew]

Hi, We have just moved and are going to be refitting our kitchen. As a consequence I was investigating the plumbing layout near the mains riser. Its a reasonably large house but surprisingly only has a 15mm pipe coming out of the kitchen floor. Mains pressure seems good though. Is that size (15mm)pipe normal for a large house?

Anyway the plumbing in the kitchen is a real mess. Years of water filters new sinks etc have produced something akin to a spaghetti junction. I am going to remove it all back to the mains stopcock and redo the pipework.

Besides a draincock immediately following the stopcock is a brass housing about 4 inches long looking little bit like a tee without but a straight through. What is it and is it necesary any more?

And in terms of pipe types I still like copper but I know that plastic is now popular, also the flexible metal braid hoses are quite handy for tight spaces etc. What are the pros and cons for using these immediately above the main stopcock and what about longevity of metarials?

Thanks for any help, Matthew

[Tim Mitchell]

In article , Matthew writes

Could you run that bit by us again? A tee without a straight through, wouldn't that be a right angle bend?

Re plastic, if you are wanting to make it neater I'd use copper. Whenever I use plastic pipe I can never get it looking neat, it's always in a wibbly wobbly world of its own, however many clips I put on it.

[Tim Mitchell]

In article , Tim Mitchell writes

Sorry to follow up my own post, but I've understood now, I think it is a double check valve for stopping backflow into the mains. I don't think you would normally have one of those on the incoming main - they are normally fitted on things like outside taps. But I am not sure of the water regs.

[Cicero]

================== Have a look at this:

- it may be what you're looking at. If so it's probably been put there to facilitate fitting of close-fitting pipework.

Cic.