On Sat, 27 Nov 2004 23:57:51 GMT, a particular chimpanzee named
"Lobster" randomly hit the keyboard
and produced:

It was definitely 2 x 12.5mm; but having said that I don't know (or recall)
what duration of fire resistance I was supposed to be going for - I was just
told that two layers of pb + skim was what was needed. Presumably the
required duration depends on the job? Mine was for boxing to protect waste
pipes passing between two adjacent properties, as I couldn't source small
enough intumescent collars, and needed the boxing anyway.

Ah. 60 minutes required, therefore at least 30mm plasterboard (or
2*12.5mm + 5mm skim). Plus sound insulation is needed.
--
Hugo Nebula
'What you have to ask yourself is, "if no-one on the internet wants
a piece of this, just how far from the pack have you strayed?"'