Diales Compendium Issue 3 - Flipbook - Page 24
It could be said that this point of view supported
by British Standard 8298-4’s recommendation
that rainscreen cladding, separated by an
air gap, should be disregarded from thermal
heat loss calculations. But is this an adequate
differentiation, as to whether or not the core is
helping prevent heat loss, it is often formed using
a combustible insulation material?
Although the term “filler” is used commonly in
the construction industry, Dr Lane also asserted
that the polyethylene core of ACM panels was
never termed thus, prior to the Grenfell fire. Her
view was supported by Mr Hyett. In this context,
his reading of “filler material” was that it “…
relates to a product or material such as mineral
wool, or PIR insulation – that is something
consisting of the same material …throughout its
make up.” Following this logic, there would have
been no requirement for the ACM core to meet
the limited combustibility requirements of 12.7 of
ADB; but should the general warning at section
12.5 regarding: “…combustible materials in the
cladding system…” have been heeded? Or was it
sufficient to ensure that the cladding surface had
‘Class 0’ designation, as required by section 12.6?
The historic use of products such as ACM cladding
in high-rise buildings is often attributed to these
alleged ambiguities within ADB; confusion over
ADB’s practical guidance status against the
statutory requirements of Schedule 1, Part B of
the Building Regulations, as well as certification
that blurred the distinction between compliance
with sections 12.6 and 12.7 of ADB, which left
designers operating within a somewhat grey, and
sometimes confusing, framework. Whilst the
question of whether compliance with ADB itself is
sufficient to comply with Schedule 1, Part B of the
Building Regulations remains open for debate.
Had the Grenfell fire not occurred, and its
immediate lessons been learnt, it is quite probable
that non-fire rated ACM cladding would still be
used on high-rise residential buildings today.
However, since the fire, the practical guidance
within ADB has been updated and clarified, and
now precludes the use of combustible materials
in the construction of external walls for high-rise
residential buildings.
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Figure 1 - Diagram 40, ADB