Kawneer - Turning over a new sustainable leaf
By John Stamp, technical consultant, Kawneer
architectural aluminium systems
Sustainable development is still largely defined as that
which “meets the needs of the present without
compromising the ability of future developments to meet
their own needs,”* and there are signs that specifiers
are increasingly moving from making decisions on
materials purchase based on capital costs to those made
with whole life costs in mind.
This may well have partly been prompted by developments
such as the holistic approach that the new Part L
Building Regulations have taken, the Government’s Code
for Sustainable Buildings and DEFRA’s sustainable
procurement taskforce.
But political correctness aside, this is where the
economic benefits of sustainability come into their own.
All the specifier has to do to compare options is run
through a three-point checklist - assess the objectives
(like the desired level of thermal performance), the
constraints (like safety or aesthetics), and the
assumptions. This is where manufacturers who have to
hand information on their product’s sustainability will
obviously be a step ahead at this point.
Specifiers in the construction industry have a raft of
decisions to make because the versatility of aluminium
means it can be used in such a diverse range of
applications - curtain walling, structural glazing,
doors, windows, roofing, cladding, architectural
hardware, heating and ventilation, shopfitting and
partitions and modular buildings.
Manufacturers therefore are coming under ever-increasing
scrutiny as to how their products and systems are
sourced, manufactured, distributed, applied, and
disposed of or recycled, and how they advise the people
who specify and use their systems. Kawneer’s parent
company Alcoa is one of the world’s top 3 sustainable
and low-carbon pioneering companies, and has pledged to
be greenhouse gas-neutral by 2020.
Kawneer managing director David Shuttleworth said: "At
Kawneer, minimising the environmental impact of our
products and operations has been a priority for many
years and is enshrined formally in our group code of
practice. We are encouraged that these topics are now
being taken more seriously by the industry at large."
Aluminium companies have invested in dedicated,
state-of-the-art secondary metal processing plants to
recycle aluminium, to the point where some do use
recycled aluminium billets 100% of the time. In the case
of drinks cans, the recycling process uses gas collected
from burning off the volatile substances in can
coatings, to provide heat for the process. Every last
bit of energy is used.
The aluminium industry has come a long way since the
existence of the metal was established only 200 years
ago. It took another 50 years or so to develop the first
commercial processes that make it the lightweight,
non-corrosive and versatile material it is today and
24million tonnes of it are now mined globally every
year.
An abundant material, the world’s known deposits of the
virgin material - bauxite - are sufficient to support
the current production rate for several hundred years
and where it is mined, great care is taken to reinstate
the land. In rainforest areas, only 5km² is mined at any
one time and it is restored with indigenous flora and
fauna. Kawneer’s parent company has itself planted more
than one million trees.
Although an energy-intensive process, more than 60% of
the electricity used to produce aluminium is generated
by hydro-electric power – in itself a sustainable
process - and the primary smelters that refine alumina
into aluminium use extensive pollution-control
equipment.
Re-smelting aluminium saves up to 95% of the original
energy needed to produce the product and the recycling
rate of used aluminium products in building is currently
80% (compared to 95% in transportation and 30% in
packaging).
The huge benefit to aluminium is that it is not impaired
by recycling and unlike other metals, the scrap has
significant value, so significant the London Metal
Exchange quotes aluminium scrap prices.
And as the overall market for used aluminium is growing,
the more aluminium a product contains, the more likely
it is to be recycled. Contrary to popular opinion, even
coated aluminium can be recycled, helping some 30% of
the aluminium used in Europe in 1997 to come from
recycling.
Recycling 1kg of aluminium can save up to 8kg of
bauxite, 4kg of chemical products and 14kW of
electricity. Today’s aluminium can contains about 40%
less metal than the can made 25 years ago, hence the
need for less energy and less raw material per can.
More than any other material, aluminium is capable of
being extruded into complex shapes and to exact
tolerances. Other metals such as steel can be extruded
but require enormous pressure to pass through the die,
rendering all but a few simple extrusions uneconomic.
It can also easily be integrated into other sustainable
building technologies such as double glazing, sun
shades/louvres and photovoltaics.
At present, 40% of the UK’s annual production of
aluminium is used within the construction industry,
which equates to approximately 150,000 tonnes per annum,
of which approximately 65,000 tonnes is extruded
products and 25,000 sheet materials.
Unlike many recycling schemes where the scrap material
is rarely re-used for the same application, being
downgraded to an application requiring lesser metallic
properties, aluminium in windows, for example, can be
recycled to make new aluminium windows.
A framing system like Kawneer’s AA®4001, for instance,
is manufactured from aluminium sections which are 100%
recyclable, with 70% of the aluminium used in the system
having been reclaimed, retaining 95% of the initial
energy invested.
This system has been used at the Mundy School in
Derbyshire which was modelled on the DfES Exemplar
Schools and is proving a showcase for CLASP and BSF
through its use of natural light and ventilation through
the design of features such as vents.
A showcase also for sustainability.
* Bruntland report
Email:
tracy@tlcpr.co.uk
Arundel Jones Associates Ltd
Hill Farm, Linton Hill, Maidstone, Kent ME17 4AL
Tel : 01622 745333
news@buildingdesign.co.uk
Registered in England and Wales No. 07334149
News Categories : Architectural aluminium systems
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