Civil Engineering Reference
In-Depth Information
Class 0 surface spread of flame. If
they are 1 m or more from the
boundary, the requirements differ
(Figure 1.55). For other examples see
the Approved Document.
Insurers' rules
Insurers' rules for the fire protection
of industrial and commercial buildings
are contained in a topic
(56)
†
which is
designed to accompany Approved
Document B (Fire Safety) of the
England and Wales Building
Regulations.
The topic lists insurers'
requirements, provisions of which are
sometimes more stringent than those
of the Building Regulations, and
contains appendices on walls,
columns, approved wall claddings,
approved lining materials, approved
fire stopping materials, and fire break
doors and shutters.
Non-combustible material
Under the Approved Document, this is
defined as any material which:
●
when tested to BS 476-2 does not
flame and there is no rise in
temperature on either the centre
(specimen) or furnace
thermocouples
●
is classified as non-combustible
under BS 476-4
●
is inorganic and contains not more
than 1% by weight or volume of any
organic matter
Any dimension over 20 m Class 0
Refurbishment
Where refurbishment is being
undertaken on buildings controlled
under the Fire Precautions Act
1971
(57)
, the fire certificate issued
by the fire authority will list
conditions which will need to be
maintained in the building,
provided the use has not changed. If
changes are to be made to the building,
however, the old certificate may no
longer apply, and application should
be made to the Fire Officer for the
issue of an amended certificate. It
therefore behoves all those concerned
with refurbishment of such buildings
to make
themselves aware of the contents of
these certificates, and indeed with
all other legislation affecting occupied
premises.
Up to
20 m
above
ground
Material of limited combustibility
Under the Approved Document, this is
defined as any material which:
●
is non-combustible, or is at least
300 kg/m
3
and does not flame when
tested to BS 476-2, nor register a
rise of more than 20 °C on the
furnace thermocouple
●
has a non-combustible core of not
less than 8 mm thickness, having
combustible facings of not more
than 0.5 mm thickness on one or
both sides
Index (I) not more
than 20 according
to BS 476-6
1 m or
more
Figure 1.55
Provision for external surfaces of walls of
any building more than 20 m high and 1 m
or more from the boundary
Fire damage
Inspection of fire damaged structures
should be carried out by competent
and experienced persons. Tests carried
out to BS 476 are not intended to give
guidance on the serviceability of such
structures after exposure to a fire.
Where the opportunity arises, tests
may also be carried out on actual
buildings. Absence of spalling or
absence of change of colour after a fire
should not be taken as evidence that
any reinforced concrete members are
satisfactory, since different aggregates
vary in their behaviour in fire.
Figure 1.56
Butted cavity barriers fixed to the sheathing of a timber framed dwelling before
construction of the outer leaf. Gaps are evident
† At the time of writing, this publication was being reprinted
in looseleaf form.
