Where any stairway links a basement with
the ground floor, the basement should be
separated from the ground floor, preferably by
two 30-minute fire doors, one at basement and
one at ground floor level (see Figure 32). In a
factory, the basement can be separated by one
60-minute fire door at basement level, or one
30-minute fire door where the basement is
small and does not present a high fire risk.
Any floor over a basement should provide
60 minutes fire resistance. For smaller premises
30 minutes may be acceptable. Where this is
impractical, and as long as no smoke can
get through the floor, automatic smoke
detection linked to a fire-alarm system which
is audible throughout the premises could, as
an alternative, be provided in the basement
area. If in doubt, contact a competent person
for more detailed advice.