How green are the RIBA Stirling Prize finalists?10 October,
2014|By Simon SturgisIt is no longer acceptable for 50-60 years to
be the assumed life of a high-carbon investment, writes Simon
SturgisLooking at 2014s six RIBA Stirling Prize finalists from a
holistic carbon perspective, who wins? Clearly the winner must be
an outstanding design with low operational energy demands. The
enduring benefit to society which comes from architectural quality
is in itself carbon efficient. Buildings which are valued and
enjoyed by their users will have a longer life.Environmental design
innovation, as well as incorporation of the latest best practice
sustainability measures, should be fundamental. This, though, is
just a part of the carbon picture. What does the whole picture look
like?A RIBA Stirling Prize finalist should also be a sound carbon
investment for the long term by demonstrating that it has made
optimum use of resources and that its design is informed by an
understanding of the buildings future life.This implies durability,
resilience, low maintenance, and ease of re-use. It is no longer
acceptable for 50 to 60 years to be the assumed life of a
high-carbon investment. When a building is assembled, it is made
from materials that are on loan from our environment. To reduce
overall environmental impact, it makes sense to use recycled
materials and to design for re-use and recycling.Of this years six
finalists, the Everyman Theatre best addresses sustainable
low-carbon design in the round, with the LSE a close runner-up.
What nudges the Everyman into the top spot is its extensive use of
recycled materials. The Everyman re-uses resources already on site,
and it is energy-efficient in use, with significant passive
contributions. It is durably built and is already admired locally.
It is a building our great-grandchildren will be able to enjoy.And
isnt this the point: to ensure that the environment in which we
live is habitable for those great-grandchildren? By contrast, I
would venture to say that two or perhaps three of this years
finalists may well be consigned to landfill before the end of this
century. This is not sustainable.The UKs most prestigious
architecture prize must encourage innovation in overall carbon
emissions reductions. James Stirling was himself a great innovator.
Stirling Prize judging should examine and encourage use of existing
structures and recycled content, life cycle analysis, flexibility
for re-use, disposal and recyclability. Ease of maintenance,
replacement of parts and ultimate disposal are all carbon issues
for the architect, and not someone elsesproblem.Buildings worthy of
being Stirling finalists should go further than meeting existing
environmental codes. This means thinking about embodied carbon and
operational carbon together. Even though standards and legislation
have yet to address embodied carbon, the Stirling Prize should
point the way, by recognising buildings which are lowcarbon in
every sense. Simon Sturgis is a partner at Sturgis Carbon
ProfilingPredicted annual operational carbon emissions plus
analysis25.5 kgCO/m- Manchester School of Art Feilden by Clegg
Bradley Studios
This is the only entry that includes a substantial retrofit.
Recycling an entire building is a great low-carbon starting point.
The new build parts of the School are BREEAM Excellent, but the
Retrofit tower is only rated Good, which is disappointing. But this
rating could be higher if the BRE gave proper credit for the
embodied carbon emission benefits of retrofit. The glazed area of
the tower has been reduced by 40 per cent, contributing to improved
energy efficiency without compromising daylight factors.The school
has a number of impressive sustainability measures including solar
thermal, rainwater harvesting, mixed mode ventilation and heat
recovery. An important feature of this building is its ongoing
post-occupancy monitoring strategy for the energy systems.The main
entrance features a sculpture which displays live energy data to
students and visitors. This will contribute to a culture of
environmental awareness, which is critical. Modifying our
individual behaviour will provide some of the biggest carbon
savings associated with the buildings we occupy.29.3 kgCO/m -
Everyman Theatre by Haworth Tompkins
The BREEAM Excellent Everyman has impressive responses to the
low carbon question. Material recycling is a major feature, with
25,000 19th century bricks and elements from the original timber
structure re-used in the new building. In addition, approximately
90 per cent of both demolition and construction waste was recycled.
So before the building was even finished, it was racking up an
impressive carbon credit.The carbon footprint of the concrete
structure is mitigated through the use of cement replacements.
Natural and exposed finishes are also predominant. Natural
ventilation is achieved with the assistance of large brick roof
towers (lifespan: 100+ years) which reduce the need for mechanical
plant (lifespan: 15-20 years). Energy efficiency in use is achieved
through the use of renewables, CHP and air source heat pumps.You
might argue that the cladding above the entrance is a carbon
extravagance. However, this is locally appreciated and enjoyed and
therefore performs an important social function. The Everyman looks
to have a very long low-carbon life.28.8 kgCO/m - Library of
Birmingham by Mecanoo architecten
The BREEAM Excellent Library uses cold water from an aquifer and
a CHP as its standout energy efficiency features. It also has a
proportion of natural ventilation and stack effect cooling/heating
via its interior voids - all good.Its most striking architectural
feature is its cladding, a series of extruded aluminium and curved
RHS circular elements covering the facade as part of a unitised
cladding system. These features represents a major carbon
investment. What are they for? There is no claim they perform a
sun-shading role and, if they did, you would expect a different
response to each facade. These decorative elements will have
carbon-intensive maintenance and replacement costs. Unitised
cladding systems are interlocking and quick to assemble, but
inflexible and do not lend themselves to localised change. Arguably
it is an inappropriate choice for this sort of building. The
building is described as having a 50-60 year design life. Is it
acceptable to use resources in such a short-term way in a publicly
funded building? What happens to the circles and who pays at the
end of 60 years?18.8 kgCO/m - Saw Swee Hock Student Centre, LSE by
ODonnell+Tuomey
Of the six finalists, the LSE student centre has the lowest
emissions and is the only one rated BREEAM Outstanding. The form
optimises natural light and contributions to energy efficiency
include a CHP, photovoltaics, intelligent controls and natural
cross-ventilation. Low embodied carbon strategies such as use of
cement replacements have also been deployed.The architects claim
the building is resilient to climate change, an important design
attitude. The building has been designed as a long-term carbon
investment which can both look after itself and be easy to fix. One
example is the south-facing perforated brick screens, which help
protect the glazing beneath from sun and rain.Natural, untreated
materials have been extensively used. Large areas of glazing are
framed with natural timber and are easy to dismantle, so the
building can be maintained over the years using natural materials
and low carbon-intensive skills. This is a building that has
thought about its future and will most likely be enjoyed in 100+
years time, much like the buildings around it.25.4 kgCO/m - The
Shard by Renzo Piano Workshop
The Shard ticks many sustainability boxes, but can a tall
building of this type ever be truly sustainable? Rated BREEAM
Excellent, the Shards principle claims to environmental efficiency
are its naturally ventilated double skin facade with adjustable
blinds in the central void, and CHP.Of interest is the relationship
between the life of the unitised triple-glazed cladding system and
the differing lengths of leases for the various uses: retail,
hotel, office and residential. Double-glazed units typically fail
after about 40 years. So around 2055 when this building will
require re-glazing or re-cladding, how will this relate to lease
cycles? By 2050 the UK is meant to have achieved 80 per cent
reduction in carbon emissions (vs 1990). How will re-glazing the
Shard relate to carbon emissions legislation of the day? This is
not looking good.Buildings of this size and shape have poor
net-to-gross and floor-to-wall ratios. In terms of embodied carbon,
towers are an inefficient way to enclose space. Tall buildings like
this are not part of a low carbon future.53.6 kgCO/m - London
Aquatics Centre by Zaha Hadid Architects
The Aquatics Centre is a prime example of sustainability
standards and legislation not delivering a comprehensively
low-carbon outcome.Rated BREEAM Excellent, the building has a
genuinely exceptional range of leading-edge sustainability
measures. An Innovation credit was awarded for use of recycled
aggregates and cement replacements. Water use and re-use measures
are also impressive. Natural light is abundant, and the building
plugs into the Olympic Parks district heatingnetwork.But the design
concept is flawed from a low-carbon perspective because the
building contains substantial quantities of steel and concrete.
Compare the Aquatics Centre with Hopkins Velodrome (also BREEAM
Excellent), which uses approximately 1/30th of the weight of
structural steel in the superstructure.Despite the list of
sustainability credentials, the building starts life with a massive
carbon debt. It is also worth noting that the annual operational
carbon cost per m is by far the highest of the six, presumably due
to the pool. So it is unlikely that this carbon debt will be paid
off
