Roof and Wall - Lane Roofing

Building Regulations
Firewall Building Regulations
The Building Regulations Approved
Document B - 2000 edition provides
guidelines on acceptable forms of fire
resistant structures encompassing
construction, material performance, means
of escape and appropriate active fire control
techniques. These are categorised in the
following requirements:
B1 – Means of escape
B2 – Internal Fire Spread (linings)
B3 – Internal Fire Spread (structure)
B4 – External Fire Spread
B5 - Access & Facilities for the Fire
Service
All of these stipulations require close design
integration in order to establish effective
building fire containment systems and
suitable evacuation procedures.
Whilst for the purpose of this brochure it is
impractical to cover all the conditions
contained within this document,
Requirements B2 and B4 are the most
relevant when considering the use of steel
cladding systems. The following information
has been produced as a guide to highlight
some of the basic criteria.
B2 - Internal Fire Spread (linings)
Requirement:
(1) To inhibit the spread of fire within the
building, the internal linings shall:-
(a) resist the spread of flame over their
surfaces; and
(b) have, if ignited, a rate of heat release
which is reasonable in the circumstances.
Classification of Linings
Location
Class
Small rooms of area not 3
more than 4m 2 in a
residential building and 30m 2
in a non-residential building
Other rooms. Circulation 1
spaces within dwellings
Other circulation spaces, 0
including the common area
of flats and maisonettes
Taken from Document B2, Section 7, Table 10
References
BRITISH STANDARDS
B5476 Fire Tests on Building Materials &
Structures
Part 3:1975 - External Fire Exposure
Roof Test
Part 4:1970(1984) - Non-Combustibility Test
for Materials Part 6:1989 - Methods of Test
for Fire Propagation for Products
All Corus Panels and Profiles cladding
products manufactured from Corus organic
coated steel meet Classification 0.
A description as to how this classification is
obtained can be found within the British
Standard 476 section of this brochure.
B4 - External Fire Spread
Requirement:
1) The external walls of the building shall
resist the spread of fire over the walls
and from one building to another, having
regard to the height, use and position of
the building.
2) The roof of the building shall resist the
spread of fire over the roof and from one
building to another, having regard to the
use and position of the building.
Fire resistance standard:
The external walls of the building should
have the appropriate fire resistance given in
Table A1, Appendix A of Approved
Document B (2000 edition).
This table stipulates specific provisions of
test for fire resistance of elements of
structure stating required method of
exposure, integrity and insulation periods
based on the distance from a relevant
boundary.
Table A1 refers to Table A2 which in turn
gives a specific breakdown of fire resistance
periods for buildings in certain purpose
groups, building heights and whether
sprinklered or not.
For example, an external non-loadbearing
wall on an industrial unit up to 20m from
ground level requires a minimum fire
resistance period of 90 minutes (nonsprinklered)
with an insulation period of
15 minutes.
All certified/assessed built up Corus Panels
and Profiles Firewall systems achieve
4 hours integrity and 15 minutes insulation
and therefore would satisfactorily meet this
criteria.
External Services:
The external surfaces of walls should meet
the provisions laid out in Diagram 36 of
Part 7:1987 - Methods for Classification of
the Surface Spread of Flame of Products
Part 11:1982 - Method for assessing the
Heat Emission from Building Materials
Part 22:1987 - Methods for determination of
the Fire Resistance of non-loadbearing
elements of Construction
Requirement B4, Section 12. A brief
summary of this diagram is tabulated below:
Provisions for external landscaping of walls
Building Distance from
Height Boundary
All Corus Panels and Profiles cladding
products manufactured from Corus organic
coated steel meet Classification 0.
A description as to how this classification is
obtained can be found within the British
Standard 476 section of this brochure.
External Wall Construction:
Classification
1m For the initial
20m index ‘I’
should not
exceed 20.
Areas above 20m
the classification
should be 0
It must be noted that even though the
provisions for external surfaces may have
been satisfied, on buildings that are in
excess of 15m above ground level the
insulation material used in the external wall
construction should be of limited
combustibility.
All insulation specified for use within Corus
Panels and Profiles firewall systems can be
deemed ‘non-combustible’ in accordance
with BS476 Part 4 and would therefore
meet the criteria of this stipulation.
British Standard 476 provides an
acceptable framework for meeting these
requirements within the U.K. and focuses
on test related physical measurement in
order to establish fire rated performance for
steel cladding systems.
Reference is made to this standard in
Approved Document B sections B2 to B4 -
Internal and External Fire Spread.
THE BUILDING REGULATIONS 2000
APPROVED DOCUMENT B - 2002 EDITION
B1 Means of Escape
B2 Internal Fire Spread (Linings)
B3 External Fire Spread (Structure)
B4 External Fire Spread
B5 Access & Facilities for the Fire Service
Firewall Systems 27