I found some so-called Class "0" cement firbre board from B&Q. It
looks very much like asbestos sheet, and appears to be made of
portland cement with some sort of fibre imbedded in it. B&Q's staff
were unable to offer much information about thier product. One
floor-walker said they sell it as an alternative to asbestos sheet,
and it is pretty much fire-proof.

I would like to know just how fire-proof it is, and at what
temperature it disintegrates or burns. What does "Class O" mean?

Does anyone have any info at all?

Thanks

Frank