82mm waste for toilet

[Vortex11]

Hi,

I am fitting a new toilet and hope to conceal the (previously boxed in) waste piping underfloor.

Problem is that there is insufficient headroom for 110mm; but I have noted that 82mm waste piping is also reasonably readily available.

With 82mm I can achieve a decent slope on the ~600mm "limb" going to the (outdoor) stack. Probably about 40mm drop

I am however rather baffled at the almost complete absence of toilet connectors to suit 82mm pipe. Some seem to be available though, like

Question.

Does anybody here have experience of 82mm waste plumbing with a WC.

Blockage is my main concern. Should I be concerned?

David

[Andy Burns]

I just looked into 82mm pipe for vent rather than discharge part of stack, so happen to have some docs to hand, according to Mr Polypipe

"It is only permitted to use 82mm diameter pipework when the outlet of the WC pan itself is less than 80mm diameter."

That seems to connect to 3½" pipe, which is not 82mm.

[Vortex11]

As it happens the ID of the WC output is 75mm!

Agreed 3.5" is 89mm but looking at the drawing I figure it should work. The "flappy seal flanges" (I am sure they must have proper name) have an OD of 3.5" but it looks to me as if it could be persuaded into an

82mm socket.

Will see in a couple of days because I just ordered one!

[Andy Burns]

So far so good ...

"finned seals" they seem to call them

The internal diameter of 82mm pipe is 75mm, so might be quite tight, McAlpine fittings generally have reasonable give, is that one made of EVA (flexible) or polypropylene (rigid)?

[Vortex11]

Actualli I was imagining going into a an 82mm socket, if necessary. We will see!

[Andy Burns]

What about the OD? unless it's very thick walled, the pan connector might be a bit waggly ...

[Andy Burns]

I don't think they're really designed to seal on the inside of a socket, only to the inside of pipe, or a spigot bend.