On Sat, 15 Mar 2008 03:32:55 +0000, a particular chimpanzee, John Rumm
randomly hit the keyboard and
produced:

No strip on the bottom, and often none at the sides either

(you can avoid the need for side strips if the door stops on the frame
are at least 25mm deep).

No longer the case. The old 1" door stops do not contribute to the
fire resistance of the door due to the different way fire doors are
now tested.

The requirement within dwellings is for a 20-minute fire resisting
door. Some BCOs will accept an FD30 door without intumescent strips
as an FD20, but strictly speaking, unless a door has been tested to
BS476: Part 22 (1987), no period of fire resistance can be guaranteed.
Very few, if any, manufacturers will test their doors without an
intumescent strip to 20 minutes (it's expensive, and the market for
FD30 doors is greater, so why waste money testing a door to 20
minutes).
--
Hugo Nebula
"If no-one on the internet wants a piece of this,
just how far from the pack have you strayed?"