Strange sized incoming cold water main, what is it?!

[alph250]

Hello all,

Right i'm re-plumbing my house as its a bit of a state! The question is though i've got a plastic cold water main which has an external diameter of 17.65mm and its black, i thought at first it could be one of these alkathene pipes which were commonly used around the time of construction (70's build, so im sure some of you oldies might know!) but when i looked at the pipe theres no engraved print on them, apparently there usually marked 'C' or 'D'. so;

Anyone know what it is?
And anyone know where I can find a compression fitting or other fitting to reduce it down to 15mm?

Thanks

 

[sonray ltd]

sounds like polyorc has a 3/8" internal dia

 

[johnmcginty]

Yep type in talbot grippa to google it is pushfit.

 

[Bernie2]

Hmm!

Sounds like alkathene-pre blue water main. Can be a problem, as there was all kinds of alkathene out around that time, each had its own set of inserts and adaptor rings, but most funnily enough, fitted Conex compression fittings if you had the right ring and insert.

They where usually marked with the BS and type info every three foot or so. But sometimes you couldn't make out what it was, it was so faint. Try rubbing a bit of chalk on the side to see if there is anything.

I can't remember if I had the old size catalogue which gave specifics, I'll have a look but I doubt it.

Seems to be BS:3505:1968 3/8" Class E 15bar OD 17-17.3mm

Try Polypipe at Polyplumb.co.uk

I rememberer using black alkathene in the 70's but as I said there where all kinds of different sorts and grades, for above and below ground, the confusion over what could be used where was fantastic.

Anyway looks like yours might be that one. You can perhaps narrow it down a bit by knowing that the water authorities of the time would only accept pipe that could take 15bar pressure as a minimum for underground use.

Hope it's helpful!

 

[alph250]

Thanks for all the responses!

hmm not sure on the sizes, i measured the pipe using verniers and its definetly 17.65mm or 0.695", unless is it lekly that these pipes expand or swell over time?! needless to say i cant find much info on it anywhere.

The house is a three storey structure with a garage on ground floor where the mains is it goes, mains pipe, adapter, 1" length of galvo, stopcock, galvo,copper T, galvo, copper, galvo etc!

I was thinking of leaving the adapter on and just getting another adapter on to this to go back to 15mm then stopcock etc. Only if the plumb merchants dont know what it is, theres one just around the corner and as the structure is quite common in the area i would 'hope' they've encountered this problem before and have all the nice answers (the glass is always half full)

I would just prefer to change the adapter as the job would be done 'proper job' and not 99% except a crappy adapter which makes my new pipework look crap!

Thanks for the responses!

 

[TGor]

Hmm also!

if this is your only incoming .. then you might consider replacing the lot! as a 10mm bore will give pressure drop problems e.g. when someone's in the shower and another tap is opened .. plastic pipes have a thick wall thus a smaller bore than metal pipes so replace with 22mm copper or 28mm plastic which will effectively have the same bore.

hope this helps

 

[alph250]

Yeah your completely right, one of the reasons im re-plumbing the house!

The pipework is a whole mix of 7/8' galvo with the odd 22mm copper or 15mm copper and the pressure drop across the system is huge!

So plan is to re-do the house, suck and see, if theres still a prob then it looks like the water main has to come out!

How deep did they use to install these pipes? (1970's)