Insulate Magazine Ecobuild 2018 Special Edition

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Exclusive Insulate Column
Driving Up Quality
Paul Forrester Technical Editor, Insulate Magazine
Car manufacturers have long sold their
products on the basis of fuel efficiency and
emissions, despite most paying customers
knowing they won’t achieve those figures. Similar
awareness doesn’t yet exist for people looking to
buy a new home, but do changes in the automotive
industry hint at a different future in construction?
A 2014 edition of Audi Magazine, the customer magazinestomer
of Audi UK, carried an article about fuel performance
and carbon dioxide emissions figures for cars. As well as
describing how the tests are carried out, there was also an
explanation of the usefulness of the results.
It made for interesting reading, not least because of the
openness with which it talked about how little relevance
the test figures had for what would be achieved on the
road. The other striking thing about the piece was how
much resemblance its content bore to the construction industry.
Controlled Conditions
Tests must be “in strict adherence with European guidelines”
and have to be done in laboratory conditions because
the “infinite variations” in road conditions, weather
and driving style would make it impossible to test one vehicle
against another in the real world.
The in-situ testing of construction is almost non-existent,
with assessment being based around software, paperwork
and the limited policing of translating design intent to site.
Statements such as, “it is not practical to test every new
car” brought to mind building regulations that allow acoustic
or air pressure testing of a sample of dwelling types.
In explaining how the figures are “for guidance only” - but
that they allow for a comparison between models from one
manufacturer or different manufacturers - it was impossible
not to think of SAP and SBEM calculations being used
to assess building compliance, and Energy Performance
Certificates rating performance without accounting for occupant
behaviour.
Uncovering Truth
Of course, not long after the article’s publication, the
Volkswagen Group became engulfed in a scandal of its
own making through the revelations that it cheated emissions
tests.
With hindsight, it’s easy to be sceptical about any apparent
good intent in the magazine article because Audi is
part of the VW Group. In truth, however, any car manufacturer
could have written it, so the validity of comparisons
between the automotive and construction industries isn’t
diminished.
If anything, the existence of an even bigger performance
gap between a car’s lab results and road performance only
serves to make the comparisons more relevant.
The reality of building performance is that energy use is
typically 30% higher once constructed than was predicted
at design stage. That is far too big a discrepancy to be explained
away by ‘infinite variations’ of occupant behaviour,
or site location and weather conditions.
Strength of Feeling
Once the full extent of the VW scandal became clear, it
was not uncommon to hear suggestions that the performance
of buildings - and housing specifically - should be
highlighted as a similar scandal in an effort to raise public
awareness.
How outraged were people really, though? In 2016, the
VW Group became the number one car manufacturer in
the world in terms of sales.
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