Introduction to Fire Safety Management

Introduction to Fire Safety Management
Typical locations where cavity barriers should be in
position are as follows:
➤ At the junction between an external cavity wall and
an internal compartment wall or fl oor
➤ In any ceiling void where a long corridor (over 12 m)
has been subdivided to limit fi re or smoke spread
➤ Between a compartment wall and the underside of
the fl oor above, i.e. above any false ceiling.
Every cavity barrier must be constructed to provide at
least 30 minutes’ fi re resistance and should be tightly fi tted
and mechanically fi xed in position in such a way so
as not to be affected by the:
➤ Movement of the building due to subsidence
➤ Collapse, as a result of a fi re, of any services penetrating
the barrier
➤ Failure in a fi re of any construction into which
they abut.
It is often the case that during alterations to a building
or its services, fi res are started in concealed cavities
and develop and spread without easily being detected.
Alterations that require a fi re resisting enclosure are often
made without consideration of their effectiveness, being
negated due to the presence of a concealed cavity.
9.4.6 Openings in compartmentation
Compartmentation is vital for the safety of the building
and its occupants. However, a building, which has compartment
walls and fl oors with no openings, has very
limited use. There are always occasions when a compartmentation
wall or fl oor must be ‘breached’ in order
for occupants to move around and the building to be fi tted
with services. It is when these necessary breaches
are made in compartmentation that it is absolutely vital
that the compartmentation maintains its integrity against
fi re spread.
The Building Regulations Approved Document limits
the openings permitted in a compartment fl oor or walls
to those for:
➤ Doors and shutters with the appropriate fi re
resistance
➤ The passage of pipes, ventilation ducts and other
services
➤ Refuse chutes of non-combustible construction
➤ Atria designed in accordance with specifi c rules
➤ Fully enclosed protected shafts
➤ Fully enclosed protected stairways.
The two types of openings in compartment walls and
fl oors that are the most diffi cult to manage once a building
is occupied are doors with the appropriate fi re resistance
182
Figure 9.15 A typical fi re resisting door
and the passage of pipes, ventilation ducts and other
services. Time and time again breaches in compartmentation
that occur as a result of inadequate fi re risk management
have allowed relatively small fi res to spread and
develop in tragic proportions.
Breaches of compartmentation are found to routinely
occur by fi re doors being faulty or being wedged open
and contractors’ works involving the routing of new
services through compartment walls or fl oors being
carried out without the necessary reinstatement of the
integrity of the compartment.
Fire doors and shutters
Fire doors – fi re doors are provided not only to allow
passage through a fi re compartment wall but also to
protect persons escaping from the heat and more importantly
smoke generated from a developing fi re.
In addition to the fi re resistance of the door and
its assembly, it is also vital, in order to protect escape
routes and prevent smoke damage to the building, that
the door limits the spread of smoke. This is achieved
by ensuring that the door effectively self-closes and is
fi tted with two types of seal; an intumescent strip that
expands when it becomes hot and forms a fi re resisting
seal around the door and a cold smoke seal which
is normally in the form of bushes or a felt material, which
prevents the movement of cold smoke.
The fi re resistance of doors is certifi ed through a
testing procedure laid down in BS 476. Fire doors can
only achieve a certifi ed rating in conjunction with its
assembly, i.e. door frame hinges, door handles, glazing,
etc. It can be understood therefore that the fi re resistance
on any particular door relies as much on the entirety of
the completed assembly as on the door itself.
A Code of Practice for fi re doors with non-metallic
leaves (BS 8214:1990) states that all fi re doors should be