On Mon, 20 Apr 2009 02:47:12 -0700 (PDT), a certain chimpanzee,
randomly hit a keyboard and produced:

I've got to fit Intumescent collars to a 110mm soil pipe and a 100mm
vent pipe, how tight fitting should the collars be?
Can I use a 110mm collar for both?

Are they both plastic pipes? If so, they are probably both 110mm
outside diameter. If you're using concertina ducting for the extract
pipe, you should really use plastic ducting, especially through floors
(or walls).
--
Hugo Nebula
"If no one on the Internet wants a piece of this,
just how far from the pack have you strayed?"