+IMPACT Magazine Issue 25

PROJECT
PROJECT
Access roads, parking areas and footpaths will be
upgraded and integrated into the natural landscape.
Disturbed land will be replanted with the indigenous and
endemic species that call the reserve home, with a focus
on plants that require little water. Landscape architect
Jacques Dohse of Planning Partners also consulted on the
incorporation of retention ponds and storm water systems
that will reduce storm water run-off, allowing water to
soak into the ground in line with the natural system.
A wetland area will also become self-sustainable
over time and add to the biodiversity of the area. Near
the buildings, the existing educational gardens will be
retained and upgraded to allow visitors to wander around
and learn about the plants themselves.
THE ARCHITECTURE
“One of the key moments in the project was when Bongani
Mnisi [Manager: Environmental Planning & Sustainability,
the client user and Project Lead] took us for a walk in
the nature reserve and explained the local flora and
fauna to us. Only then do you realise the significance of
little things that may otherwise have gone unnoticed,”
says Martin Pallmann of his experience on the project.
Pallmann headed up the team from GAPP Architects.
He goes on to explain that the buildings are arranged to
form a “campus-like assembly with outdoor ‘classrooms’,
where green building elements will be showcased for
educational purposes”. Creating usable outdoor “rooms”
out of the interstitial spaces was a significant part of the
design approach.
One of the existing buildings was upgraded
and made into student accommodation.
The “campus” provides usable and
interesting public spaces inside, in
between, and around the buildings.
The old administration building and manager’s cottage
were refurbished after a careful approval process with
Heritage Western Cape, facilitated by GAPP’s senior
architect and heritage practitioner, Kobus van Wyk. The
new buildings are steel portal-framed structures with
brickwork infill and a polished concrete surface bed,
topped by double-pitched soft roofs with PV arrays on
the north-facing sides. The new roofs, of modern metal
sheeting, are designed to be differentiated from, yet
respectful of, the corrugated roofing on the heritage
buildings. External wall treatment is a combination of
cement-washed semi-face (NFX) brick and plaster. The
combined effect ties in respectfully with the heritage
buildings on the site, and is reminiscent of rural farm
barns, which is not out of place in the context.
Pallmann adds that all exposed timber elements in the
roof structure and pergola is saligna (bluegum/eucalyptus),
which is locally sourced and supports invasive species
removal programmes. All timber is FSC-certified. Terraced
building platforms were created using gabion walls made
with granite found on the site.
WATER SAVINGS
Powrie explains that water and energy efficiency were
the main two targets they wanted to hit on this project.
They were the categories that achieved the highest scores,
although commendable scores were achieved across all the
categories of the tool. Potable water use is closely monitored
by a sophisticated, cloud-based monitoring network so that
water usage can be understood and adjusted as necessary.
The manager’s cottage was assessed for heritage value,
and respectfully upgraded and given a new lease on life.
The project team were shown around the reserve and
taught about many small aspects of nature so that
they could better understand the nuances of the site.
Low water fittings were installed throughout. Municipal
water is utilised only for potable requirements, such as
kitchen sinks and hand-wash basins, while black water is
treated on site, and used for irrigation and to flush toilets.
“Designing a sewage effluent treatment plant that is
simple to maintain and minimises potential breakdowns
was one of the biggest challenges of the project”, says
Powrie. Harvested rainwater supplements the water
system. The building achieves a 98% reduction in potable
water use as compared to a notional building benchmark.
ENERGY INTERVENTIONS
The building uses high-performance vision glazing,
which reduces glare and promotes external views for the
occupants of the building, but also reduces the need for
electric lighting. All light fittings are low energy LEDs
and are linked to occupancy and light-level sensors to
prevent them being on when they are not needed. Enclosed
offices and the multipurpose hall have fresh air ventilation
facilitated by louvres and mechanical assistance. In
winter, the multipurpose hall and selected areas of the
administration building are heated by under-floor heating.
This low-energy heating system comprises a closed water
pipe system cast into the concrete surface bed. Heated
water is pumped through the pipes and, facilitated by the
thermal mass of the concrete floor, heats up the spaces.
The building roofs support a 50kWp grid-tied photovoltaic
solar system, as well as a 3kWp backup for a 200-litre solar
geyser. These installations reduce the peak load on the
coldest day of the year by 74%. As the building does not
The buildings and their relationship
to – and respect of – the surrounding
landscape was a large design driver.
Existing buildings were recognised
for their heritage value and will
undergo respectful upgrades.
require mechanical cooling, only heating, the peak demand
is always in winter. This was achieved through excellent
passive design and energy modelling to verify the thermal
comfort of the building in summer and winter. During
off-peak demand times, the solar installation will provide
a much higher proportion of the building’s needs.
BRINGING IT TOGETHER
As well as the main interventions around energy and water,
indoor comfort was an important focus of the design. Most
occupied spaces have access to external views of gardens
outside, and the specialised glass maximises daylight while
minimising glare. Carbon dioxide (CO 2) sensors monitor
air quality indoors and these are linked to the fresh air
system so that fresh air intake will automatically increase
if the CO 2 levels get too high. Added acoustic treatments
also help to create a comfortable indoor environment.
A waste management plan was set up, including on-site
recyclables sorting facilities. A building users’ guide was
put together to help in educating and training the building
occupants as to how the building should be operated to
achieve the best operational sustainability. This guide
includes education around the installations and how they
work, the waste management strategy and encouragement
to use public transport, shared transport, bicycles or
hybrid-type vehicles. Locker and shower facilities are
provided to encourage cycling or walking to work.
IMPACT AND IMPORTANCE
The City of Cape Town, as signatories of the C40 network
of large cities, has included net-zero carbon building goals
within the city’s Climate Action Plan in line with global
best practice. The fast-approaching 2030 goal is that all
new and existing municipal assets (excluding industrial
plants) are to be net-zero carbon in terms of operation.
The alignment of major retrofits of municipal assets, such
as the Bracken project, with the net-zero carbon goals is
a great example of the city showing leadership in this area.
As this asset will be around for years, it is important that
it is designed with greater efficiencies.
The Bracken project “has achieved ‘net-zero carbonreadiness’
for its operational energy, with formal
certification being pursued, and nearly net zero for water”,
explains Pallmann. “The design collaboration of all the
professionals was a great experience, demonstrating how
easily good design can achieve 5-Star ratings without
excessive budget requirements.”
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POSITIVE IMPACT ISSUE 25
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