Pipe dimensions and drink!

GrumpyGrampa · Mar 8, 2018

I'm not a plumber. I can't get my head round plastic waste pipe dimensions - there's so many of them? I get that 32 mm is 1.25" and 40 mm is 1.5" (internal diameters) but what's the difference between "solvent weld" and "compression" as far as compatibility is concerned?

For example, on a 32 mm P trap, the inlet is 32 mm and has a "compression" fitting - I get that.

Will a 32 mm "solvent weld" pipe fit that "compression" joint?
Do I have to buy a 32 mm pipe that is not "solvent weld" - what would that be anyway?

Maybe I'm not making self clear, so if anyone can explain the mysteries of waste pipe sizes and comparable joints I'd really appreciate it. In other words "what fits what and what doesn't".

Riley · Mar 8, 2018

Compression and solvent weld tends to be compatible. Push fit can be smaller bore to suit specific fittings

ShaunCorbs · Mar 8, 2018

Compression will fit either aslong as the size is there

But solvent weld pipe can't be used with push fit

Riley · Mar 8, 2018

And you didn’t mention drink but I’d love one

rpm · Mar 8, 2018

Riley said:
Compression and solvent weld tends to be compatible. Push fit can be smaller bore to suit specific fittings

The O/D is different size as well. 😉

GrumpyGrampa · Mar 8, 2018

Sorry guys.....I must be thick or in need of a drink but I still don't get it. How sad am I, spent the last couple of hours on line and with the Screwfix catalogue but still don't get it.

rpm · Mar 8, 2018

GrumpyGrampa said:
Sorry guys...I must be thick or in need of a drink but I still don't get it. How sad am I, spent the last couple of hours on line and with the Screwfix catalogue but still don't get it.

Go to your local B&Q shed and you will see the difference in the pipe sizes straight away.

Riley · Mar 8, 2018

What is it you don’t get mate? compression will go onto solvent weld no problem. So if you buy a 1.25”/32mm elbow it will go onto a length of 1.25”/32mm solvent weld pipe