How do you know if a pipe is imperial or metric?

[DIYBaz]

Hope someone can help me...

I'm trying to T in to these 2 pipes using speedfit. Bit concerned as to the colour difference though. The top one is hot (from tank) and the bottom cold (mains). Is it just condensation, etc. that has caused this, or could it be an older, & therefore imperial pipe? How can you tell???

Thanks!

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• DIYBaz
• 27 Jun 2008
• 1

 

[Gasguru]

Get some vernier calipers or

look for a fitting that will have 22 stamped on it for metric or

wrap some wire around the pipe several times and measure the lenght (pi.d etc)

 

[Newboy1996]

Copper pipe looks a different size when tarnished. But I would go to the plumbers merchant and get a compression T, 1/2''X1/2''X15mm. You can usually take stuff back if they are any kind a merchant!
Brass fitting (or copper) are much better than your Speedfit parts anyhow!

 

[gas4you]

How old is it? Do you know when it was installed?

It is very easy for us with a van load of fittings, we carry 22-3/4 adaptors all the time so can't get caught out.

You may be best to get 4 of these, then if you need them you can convert to 22mm for the 'speedfit' fitting to fit onto.

 

[DIYBaz]

Thanks for the quick replies, forgot to mention it's 15mm / 1/2".
I'll have another look for markings on the solder joints, not found any so far though.

 

[gas4you]

If you used solder/compression fittings, then 15mm will fit 1/2" ok, just a little bit tight.

 

[wiggikins]

Conex fits as well!

 

[DIYBaz]

How old is it? Do you know when it was installed?

It is very easy for us with a van load of fittings, we carry 22-3/4 adaptors all the time so can't get caught out.

You may be best to get 4 of these, then if you need them you can convert to 22mm for the 'speedfit' fitting to fit onto.

The house is 150yrs old, not sure how long there has been a bathroom, but the existing one was fitted in 1986 I think (hence it's time for a change!). I just don't know if it was a suite swap, or full re-plumb, the the pipework could be older. No sign of anything suggesting sizes on any accessible solder joints, but this one says ">B< 86", I think, British, 1986?

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• DIYBaz
• 28 Jun 2008
• 1

Ahh, for a van full of fittings. I'm in enough trouble for having a cupboard and shed full!

 

[Agile]

The house is 150yrs old, not sure how long there has been a bathroom, but the existing one was fitted in 1986 I think (hence it's time for a change!).

I doubt there was much plumbing when it was built!

I have an 1860 cotttage and it obviously did not have any electricity or plumbing when it was built. It still does not have any lighting downstairs except anything plugged in!

Copper pipe started to be used about 1954 and the inperial/metric changeover was about 1970.

So anything as recent as 1986 will definately be metric.

Tony

 

[TicklyT]

Without a vernier or micrometer, you might be able to check the diameter by setting an adjustable spanner to just fit over the pipe, and
compare the 'feel' of the fit with a scrap of pipe of known diameter.

Bear in mind that you are looking at a difference in diameter of much less than a millimetre. It may not seem a lot, but it's more than enough to stop things fitting.

Most 1/2" imperial pipe can be made to fit 15mm fittings with the help of some emery cloth to 'clean off' the difference, but there are some that just won't. Best make yourself a 'get out of trouble' backup plan before cutting anything.

I would not attempt to use pushfit fittings on a pipe if I wasn't sure it is exactly the correct size for the fitting.

You will definitely need adapters to mix 22mm and 3/4".

 

[DIYBaz]

Thanks all! Will get an imperial fixing just incase it all goes wrong, but I'm 99% sure it's metric. Found a solder joint that I could access that looks to be on the same kind of discolored pipe with 15mm on it. Oh, and the other marking was >B< 864 (BS864) so all is well.

Thanks for the advice. Old houses do have a bit of a tendency to present a new surprise with every job!