the linings of the enclosure. But this underlying
information has been omitted from Approved
Document B, so we need to ensure that it is
remembered when we stretch the limits of risk,
as in `high density'housing or `mixed use'
developments.
Modern methods of construction
The terminology seems to have been spurned by
insurers, who face enhanced risks due to building
methods that have no history in fire, or that
include features that could well introduce
significant risks.
The relatively recent tendency to the use of pre-
fabricated pods is one such issue and demands
that the vertical and horizontal spaces between
pods include effective barriers to the passage of
fire, especially where services perpetrate the
spaces and penetrate the walls/floors of the pods.
Without such measures, the assembly could create
a perfect convection tunnel for fire spread.
To overcome these great concerns, new
methods of fire test have been required by insurers
to fire test the entire pod assemblies. The substi-
tution of materials in the pod construction needs
to be carefully understood and possible banned,
since minor changes on cost can have dramatic
consquences in fire.
In previous times, the food industry became
acutely aware of the fire hazards associated with
some types of combustible cored sandwich panels.
So much so, that AD/B 2000 introduced a new
Appendix F. Yet six years later whilst Volume II still
includes a dedicated Appendix F which highlights
the significant hazards and risks, the same fire
guidance is missing from AD/B Volume 1 for
dwellinghouses! Building methods are not limited
to one sector of construction anymore!
Fire check list
If a fire occurs, what will happen in the building
being considered? Is the standard guidance still
relevant? Have new hazards been introduced?
Have the risks been increased or overlooked? Have
the fire measures been increased?
The fundamental advice is relatively simple:
Keep fire in the box, or out of the box
Ensure fire stays in the room of origin and
cannot pass from room to room
Ensure the walls can prevent passage of fire
Ensure hidden spaces behind, below or over
walls include adequate fire stopping so that
unseen spread of fire is prevented
Ensure fire resisting systems and fixings have
not been substituted for cheaper ineffective
alternatives
Ensure fire stays outside the building and
cannot enter via walls, services or roofs
Note that `sprinklers'cannot protect every part
of a building
Ensure the building products that have been
tested for fire, are the ones being used, and are
suitable for the application
Prevent substitution of products unless relevant
test evidence or rules permitting change are
clearly available and relevant to what has been
done
Has the fire load of the building been increased
or decreased?
Conclusions
As for case histories, the original sustainable building
was obviously the third building in the story of the
Three Little Pigs. You'll remember that the three little
pigs built houses from straw, sticks, or bricks. Two
of the buildings proved not to be sustainable at all
to the wolf's huffing and puffing (or wind?). But the
other building, which took longer to build,
survived all the huffing and puffing and proved a
useful and sustainable home for the third little pig.
OK, it was about wind not fire and it was a fairy
story, but it serves a point.
One last thought. Does high density housing
also have a more open plan design and little
barrier to fire spread? Looks good, but what stops
the fire? IFP
INTERNATIONAL FIRE PROTECTION 87
PASSIVE FIRE PROTECTION FORUM
stainable
an issue?
The European classifications for Reaction to Fire of the linings
exposed to fire (classes A1, A2, B, C, D, E and F) are based on
the fire growth FIGRA index of the linings of the enclosure.
But this underlying information has been omitted from
Approved Document B, so we need to ensure that it is
remembered when we stretch the limits of risk, as in `high
density'housing or `mixed use' developments.

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