The theme of this
year’s Glass Supper is Firmitas,
Utilitas, Venustas (Firmness, Commodity, Delight) from Vetruvius’ elements
of architecture. The theme provides an
excellent opportunity to reflect on the importance of the building envelope as
it combines functional requirements with performance and aesthetics. The strap line of the event is: Where will the architectural glass industry
be in 100 years time? In times of
economic and environmental challenges it is quite appropriate to consider how
Architecture will undergo changes and how these changes will impact on the
construction industry. It is both
interesting and relevant to consider how new drivers including legislation will
bring about changes at different scales – from urban design to material
science. At the Glass Supper we will be
focusing principally on architecture and glass, current challenges and future
opportunities. High performance
buildings with low environmental impact require collaboration across design
disciplines and supply chain. The aim is to create durable and
resource-efficient buildings of high architectural standards – More with Less is the overarching
ambition. The devil is in the detail and
so besides much-needed technological progress and a deeper understanding of
fundamentals it is of paramount importance that designers are empowered to
adequately consider high performance solutions at the early project
stages. The designers will need new
skills in the future and they will need access to the right information from
suppliers and contractors. While the
need for interdisciplinary working and integrated design has been acknowledged
for years, legislation is likely to require closer links between designers and
supplier to meet the stricter regulations of the future. It is well-known that building regulations
will never represent cutting edge solutions – That is not the role of
legislation. The environmental policies on
the other hand will drive change and we all need to reflect on our own role in
a changing set of circumstances.
Thought-leaders set new standards and – by doing so – aim to secure a
place in the future marketplace for high performance building solutions. Innovate or stick with business as
usual? Lead or follow?
HIGH PERFORMANCE
AND LOW IMPACT
One definition of
a successful building project is “a project that will meet or exceed the
Client’s expectations, be delivered on time and on budget”. How do you then define high performance? Well, it depends on the point of view. The term high performance building will
typically cover aspects of durability, energy savings, occupant comfort, and aesthetics. The specific context and the Client’s
requirement will determine which of these aspects are of high priority and
which are negotiable. Increasingly, low
environmental impact is seen as high performance. By some forward-looking designers it is even
seen as a given and not really the subject of much discussion.
Visionary clients
and developers – with the help of their designers – target high performance
because of its impact on corporate image, staff retention, and potential
savings on operational costs.
Comparatively less visionary clients and developers will follow suit as
legislation tightens the requirements. Environmental
rating schemes are meant to affect the way projects are delivered, forcing
project teams to work together more closely and assess options early on in the
project.
Some clients and
project teams aim beyond code, and
target environmental ratings which are not strictly required by
legislation. However, ambitious targets
can be hard to justify unless the design team can provide evidence and
demonstrate that the cost premium is not excessive. The onus is therefore on the design team – in
close collaboration with contractors and suppliers – to develop and communicate
solutions, which offer design advantages without incurring excessive or even
prohibitive cost premiums. In a sector
where the focus traditionally is on first costs a paradigm shift is required if
due credit is to be given to high performance.
Add to the perceived cost of high performance the
aesthetics and the fairly delicate discussion about architectural quality. This is the Delight element - Venustas - which is both subjective and
often difficult to define as it encompasses qualities such as light and shadow,
transparency and reflection, colour, texture, materiality and form language.
TRANSPARENCY AND
BEYOND
Over the past
decades, highly transparent facades have become almost the default expectation in
high end commercial developments. For
these systems to perform to the ever stricter energy performance requirements
they are often realised as so-called double skin facades, which is an effective
way of offering variable performance and a high degree of transparency when
solar shading is not required. The
variability of the facade including the shading system in effect becomes an
important part of the architectural expression.
Thus it is possible to offer high performance though dynamic
systems. The premium for these solutions
is more often than not justified in an architectural discussion where
transparency is a key performance parameter or a fundamental requirement.
Progress is being
made in the field of switchable glazing as a means of controlling transmission
of solar radiation within the glass itself.
Liquid crystal display technology is being used in privacy applications
and the potential in daylighting application is being explored. Also here, Dow Corning is actively pushing
the envelope, introducing silicon science in this new field of high performance
architectural applications.
The pressure to
reduce carbon-intensive cooling in buildings has led to a reduction in the
‘default’ fully glazed facade. Architects
are finding new forms of expression, where the non-transparent (non-vision)
part of the building envelope gains prominence as an alternative aesthetic for
energy efficient buildings. In this
context there is growing interest in materials and geometry as ways of breaking
up the building elevations and moving away from the now conventional spandrel
strip and floor-to-ceiling vision glass.
We are witnessing a trend where the building envelope becomes colourful
and in some instances even playful – again adding an element of delight.
Reducing the
vision area is obviously a very efficient way of dealing with solar gains and
the resulting, carbon-intensive cooling.
And obviously the impact on daylight availability should always be
considered to provide occupant visual comfort and reduction of energy used for
electrical lighting. As the vision area
reduces and the architectural language starts to involve potentially complex
detailing of the insulated parts of the building envelope, the thermal performance
of the facade depends closely on how the insulated areas are detailed and in
curtain walling the effect framing needs to be taken carefully into account.
The thermal
performance of curtain walling needs to be assessed for the whole assembly,
including vision area glazing, insulated areas, and – crucially – the
framing. Projects with relatively
limited vision area percentages and complex detailing of the opaque, non-vision
areas will increasingly require high performance thermal insulation to meet performance
requirements given common space constraints.
One such novel solution utilises vacuum insulation panels (VIP) as a
means of offering the highest thermal performance within a given available
thickness or – interestingly – compacting the thickness of curtain walling for
a given performance requirement. Dow Corning’s architectural insulation modules are based on well-known IGU
technology, enhancing the performance of non-vision areas through integration
of fumed silica core VIP solutions.
THE SPECIFIER AND
THE SUPPLIER
In a sector where
there is no ‘one size fits all’ and virtually every project is different there
is inevitably an element of risk management, which stands in the way of project-specific
optimisation. In a time where the
economic climate and the environmental agenda present challenges, there is an
increasing focus on integrated project delivery. Important design decisions are made at the
outset of projects with subsequent changes being potentially both complex and
costly. Therefore, as environmental
ratings creep up the agenda and priority is given to early stage optioneering, the relationship between
the design team – or the Specifiers – and the suppliers is of paramount
importance. Why? - Because the design team can only ever develop
successful solutions if they have access to detailed information on relevant
options. The suppliers in turn need to
be able to articulate in an appropriate and relevant format the characteristics
of their offering, including performance metrics and design constraints. This working relationship will eventually
lead to the development of novel solutions based on feedback from cutting edge
project work and the experience of highly skilled people.
COST, VALUE, AND
WORTH (GREEN IS THE COLOUR ...)
High performance
is desirable for an owner-occupier due to long term benefits. To a commercial developer, however, high
performance is typically more interesting in terms of marketability as environmental
performance becomes a central commercial parameter in negotiations. Environmental ratings are increasingly seen
as a differentiator in the commercial market, with prospective tenants
comparing the ratings of property on offer – all other things equal. It is likely that there will come a time
where property cannot be let or sold if its energy performance certification
falls short of certain thresholds stipulated by regulation. In such situations building energy
performance translates into capital value as upgrades will have to be factored
into the negotiation. This aspect will
inevitably affect decision making which, incidentally, is the purpose of the
policy directives. And then there is the
question of planning permission, which can depend on convincing evidence of
environmentally conscious design principles.
This can be a key element in terms of technical and commercial risk as
it can be costly and time consuming if planning against expectation is not
granted and redesign turns out to be necessary.
Then there is
another aspect of Design, which pertains to the high end of the property
market, where aesthetics and choice of materials impact on market value. The client brief will set out the
requirements and the designer will be chosen with due regard to reputation and
ability to deliver such high end projects.
In these situations, the designers ability to consider appropriate
technical solutions early on is likely to prove critical to proving the
feasibility and avoid costly abortive work.
In addition to the
crucial durability of solutions, a key component of environmental performance
is the lasting qualities of buildings. A
quality building is more likely to be looked after by its owners and users and
it is more likely to be adapted to changing requirements over time. The quality comes through in carefully
crafted fabric and detailing as well as the nature of the space within and
around the building. Future proofing
buildings through high performance will inevitably add to their worth and this
should ultimately translate into commercial value.
It is not all doom
and gloom as progress is being made on many fronts including materials science,
building envelope technology, and design tools.
High performance building solutions will require new solutions bridging
sectors perhaps not conventionally or traditionally associated with
construction. The ability to modify the
properties of construction materials will cater for enhanced performance and
durability, provided that the materials are used appropriately. Outside of sealants and structural glazing,
silicon science is a field which is not widely considered part of the high
performance building arena. Well, that
may change as Dow Corning continues to collaborate in pursuit of high
performance solutions with low environmental impact on the route to the net
zero buildings of the future.
