This is a sort of DIY question since my business is moving to new
offices and we are doing some modifications ourselves.

We are building some more offices on a mezzanine floor above some
existing offices. The mezzanine floor is wooden joists with chipboard
flooring. Beneath the joists is a suspended ceiling with 600x600 tiles.

The BCO wants 30 minute fire protection for this mezzanine floor. This I
agree with. Our suspended ceiling contractor says that the existing
ceiling tiles provide 30 minutes fire protection, provided that any
recessed light fittings are properly hooded. He has given me the
manufacturer's specs for the ceiling tiles showing this. The BCO says
that it does not provide the protection and we need to plasterboard the
underside of the joists to provide the fire protection.

I don't want to antagonise the BCO by arguing that he's wrong, but I
don't want to do a lot of extra work if it's already suitable. Advice
from the panel please.
--
Tim Mitchell