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The office development,
Canolfan Hyddgen (‘Stag
Centre’), was built to
Passivhaus standards
What the CIBSE awards
judges said: ‘Much hard
work has been done to get
the energy demand down
–and the energy monitoring
data has been provided
to show that this has been
achieved. There is also clear
evidence of good
user feedback’
36
BREEAM Excellent rating. A pre-requisite of
funding was that the grant had to be spent
by mid-2008, which gave JPW Associates
less than eight months to dovetail the
Passivhaus and BREEAM design criteria
before construction commenced.
From the outset, however, it proved
difficult to satisfy both the BREEAM
and Passivhaus Institut rating systems;
for example the Passivhaus calculations
are more rigorous and exclude spaces
such as cupboards that do not need to be
heated from the building’s floor area. The
Passivhaus Planning Package 2007 was
the primary energy calculation tool used
by JPW Associates. However, TAS software
was used to model the internal
air movement and to provide
values for Part L2 Building
Regulation’s compliance and to
check summer overheating risk.
As a result, JPW had to duplicate
much of the design data.
‘Creating two sets of data was
time consuming and added
to design costs,’ explains John
Williamson, technical director of
JPW Associates. Williamson adds
that he would be happy to design
future schemes to be compliant
with both rating systems
providing the client is prepared to meet the
additional cost.
Orientation
The site was occupied by a dilapidated school
art block building dating from the 1850s,
which had disintegrated beyond repair and
was to be demolished to make way for the
new building. The planners insisted the
new scheme fit within the footprint of the
original building, without exceeding the
height of the roof ridge. Not only did JPW’s
design succeed in this task, it also ensured
that the old building was incorporated into
the new office by reusing the roof slates,
while the bulk of the building itself was
crushed and used in the construction of
drainage systems and soakaways on site.
The two-storey scheme is orientated with
its glazed front facade facing south. Offices
and meeting rooms are located around the
building’s perimeter to take advantage of
daylight, while the three IT teaching rooms
are located at its core, one on the ground
floor, two on the first. An access corridor
and break-out space between the southfacing
glazing and offices and IT suites
allows low-angle winter sun to enter the
building on both floors without dazzling
the students.
‘Although Mid Wales experiences a fairly
CIBSE Journal April 2011 www.cibsejournal.com