Connecting old to new water main

carryoncamping · 12 Aug 2006

I'd like to connect an old black Alkathene water main (22mm or 7/8" od) to MPDE blue pipe (od 25mm).

I went to Plumb Centre and they told me they don't make connectors! (I know they do as I've seen the Water board use them).

So how do I connect them?

micky p · 12 Aug 2006

it will probably be 22mm diaameter so just get 25mm blue alk by 22mm copper connector. If it is imperial then get an imperial olive and bobs your uncle. Plumb center are usless where i live. never have anything like that on the shelf.

and they have people on the counter that don't have a clue....You will need liners for both pipes as well. 25mm blue alk shouldn't be a problem but you should be able to get a 22mm black alk liner from a good plumbers merchants

carryoncamping · 12 Aug 2006

micky p said:
Plumb center are usless where i live. never have anything like that on the shelf. and they have people on the counter that don't have a clue....

You're not kidding! I asked for a compression joint and the woman behind the counter said "What's a compression joint?" I kid you not!!!

Thanks for the reply.

micky p · 12 Aug 2006

well not much chance of finding a 25mm x 22mm compression one then is there

Try another plumbers merchants. Sometimes there are good local merchants that stock nearly everything.

Gasguru · 12 Aug 2006

If your out in the sticks the best places for underground fittings are the farming/country stores.

chrishutt · 12 Aug 2006

Black poly pipe (nominal ½") has an OD of 21.5mm, same as imperial ¾" copper. Adaptors are available, but you need the correct liner for the ½" poly.

carryoncamping · 12 Aug 2006

chrishutt said:
Black poly pipe (nominal ½") has an OD of 21.5mm, same as imperial ¾" copper. Adaptors are available, but you need the correct liner for the ½" poly.

I more knowledgable Plumb Center employee said my black pipe was Class C. What does the class refer to, is it wall thickness?

chrishutt · 12 Aug 2006

Yes, it was the most common pipe wall thickness. Class D was thicker and you could even cut threads on it. The insert should be correct for class C (if that's what it is - it should be written on the length of the pipe). The OD will be the same in any case.

doitall · 12 Aug 2006

BSS, Pipecentre, Jewsons, most large builders merchants, and farmers stores, John Wallis Tit, area good place if you have one locally.

'Philmac' is what you want with the correct inserts for the two pipes, best to take a sample or get the writting on the side of the pipe.

BS-1972 LD-C light blue insert.
BS-1972 LD-D light green insert.
BS-3284 HD-C dark blue insert.
BS-3284 HD-D dark green insert.

Nige F · 12 Aug 2006

carryoncamping said:
micky p said:

Plumb center are usless where i live. never have anything like that on the shelf. and they have people on the counter that don't have a clue....

Click to expand...

You're not kidding! I asked for a compression joint and the woman behind the counter said "What's a compression joint?" I kid you not!!!

Thanks for the reply.

You`re not wrong

I ventured toward the coast once to a job and found plumb center in with pipe center and another center

After waiting for a while I was told a simple waste fitting was not @ this counter but across the yard @ pipe center

FFS.....I said why not put up a sign ...we only get regulars here and they know ........tosspots all

Water Systems · 12 Aug 2006

chrishutt said:
Yes, it was the most common pipe wall thickness. Class D was thicker and you could even cut threads on it. The insert should be correct for class C (if that's what it is - it should be written on the length of the pipe). The OD will be the same in any case.

LDPE is black in colour rather than the current metric MDPE (blue).
Two main types of LDPE were used: Class C and Class D. Class C has a thinner wall than class D. You may find the type printed on the pipe. In both 1/2" and 3/4" pipe, internal and external diameters differ.

BES (www.bes.ltd.uk) sell fittings to convert from Class C 1/2" to black or blue MDPE.

If the internal bore is 1/2" (15mm). A standard 22mm compression joint will go over the pipe, as long as you still use the existing pipe insert. The existing olive on black LDPE pipe, will be old imperial 3/4". This can be used inside a 22mm compression fitting on LDPE pipe. Imperial 3/4" olives are available. The inserts for Clas C and D are available too, but difficult to find.

Wrap PTFE tape around the olive before tightening.

carryoncamping · 12 Aug 2006

Water Systems said:
LDPE is black in colour rather than the current metric MDPE (blue).
Two main types of LDPE were used: Class C and Class D. Class C has a thinner wall than class D. You may find the type printed on the pipe. In both 1/2" and 3/4" pipe, internal and external diameters differ.

BES (www.bes.ltd.uk) sell fittings to convert from Class C 1/2" to black or blue MDPE.

If the internal bore is 1/2" (15mm). A standard 22mm compression joint will go over the pipe, as long as you still use the existing pipe insert. The existing olive on black LDPE pipe, will be old imperial 3/4". This can be used inside a 22mm compression fitting on LDPE pipe. Imperial 3/4" olives are available. The inserts for Clas C and D are available too, but difficult to find.

Wrap PTFE tape around the olive before tightening.

I'm a bit confused

I've just had the digital calipers on my black pipe and measure 21.5mm od and 15.5mm id.

Why am I confused? 1/2"=12.7mm not 15.5mm or do imperial measurments for pipework use the internal rather than external diameter for the gauge?

Anyway I've had look at the website www.bes.ltd.uk and I'm sure they have the fitting but not sure which one. Any pointers much appreciated.

Thanks

doitall · 12 Aug 2006

Its wrote on the pipe

then order as per my first post, or ask when you have found the details

chrishutt · 12 Aug 2006

½" is a nominal size. The actual bore (ID) is often bigger, so lucky you. Nominal sizes are based on old standards for steel tubes which determined the OD (21.5mm for nominal ½") since that needs to be constant to allow for threading and connecting to fittings. When copper and polythene tube came along the same ODs were adopted, at least until metrication completely confused the issue.

carryoncamping · 12 Aug 2006

doitall said:
Its wrote on the pipe

then order as per my first post, or ask when you have found the details

The Pipe has BS-1972 which is followed by an inverted triangle with a squiggle in it followed by Class C.

I'll take a trip to a one of the companies you mention with the pipe.

Cheers

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Connecting old to new water main

Water Systems

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