Curtain Walling Energy Performance - Next Generation

Energy consumption in buildings account for approximately 40 per cent of the global energy consumption and regulations are getting ever stricter in an effort to meet targets set at international and national level.  Ultimately, near zero carbon emission buildings will become the norm and this puts pressure on the building envelope to perform to higher standards than current practice.

In a time of ever stricter energy codes, high performance is seen as a means to an end – Empowering the Designer to deliver high quality architecture with low environmental impact.  We are talking about Design Freedom.

Novel solutions include architectural panels – robust products which can be handled during assembly and installation.  The technology is that of insulating glazing with vacuum insulation panel (VIP) inserts offering enhanced thermal insulation in compact units.  The finish is optional and the thickness is driven by performance requirements.  Or – as is often the case – the solutions offer maximum thermal insulation where a thin envelope is desired or required.  Potentially the thermal performance of a conventional wall is achieved within the space of a conventional glazing unit opening up new opportunities for architectural design.  The first projects have been realised already, spanning from retrofitting of historical buildings with architectural and space constraints, to new build rain screen cladding solutions with high performance.

The fact that vacuum insulation panels offer the performance of a conventional insulated wall contained in a glazing unit opens up new architectural avenues and breaks down some of the barriers otherwise posed by stricter energy regulations.  Examples of design freedom offered by high performance include the ability to increase the percentage of vision area, additional play with geometry such as layout and 3D form language – all due to enhanced performance in the insulated areas, offsetting the performance of vision area, increased transmission area, and linear thermal losses.

In a time where the energy performance of buildings needs to be addressed not only by visionary designers and clients, but across the board, the challenge is to not sacrifice high design freedom and quality architecture.  The performance of curtain walling has been enhanced incrementally over the past decades and it is reaching certain limits mainly due to the need for vision area and the inevitable effect of the framing.  Well, a step change in insulation performance may quite possibly offer new opportunities for curtain walling in a world of High Performance Building.

The Decade of the Facade Engineer

“This could be the decade of the facade engineer.” I took over the chair of the Society of Facade Engineering in 2009 and made this bold statement at my annual address in 2010. During recent years, there has been much talk about integrated design and the need to work across traditional boundaries between disciplines. It is generally accepted that collaboration from the early design stages is a prerequisite for integration and successful design. The impact of the building envelope on building performance and architectural expression – together with the fact that the building envelope easily represents up to 25 per cent of construction costs – means that the focus on this field is increasing. Clients and investors need to manage risk and control costs, while meeting the energy performance standards set out by ever stricter regulations. The more visionary investors have long ago latched on to Sustainability as good business, while comparatively more conservative investors gradually follow suit as a result of legislation and market pressures. It is the classic stick and carrot analogy. Financial pressures combined with Sustainability as a relatively new driver together lead us towards a paradigm – a new way of designing and delivering buildings. The building envelope is where the disciplines overlap and this, incidentally, is where a multitude of different inputs need to be considered to achieve a product which satisfies the many often conflicting requirements.

The building envelope fascinates because of its obvious impact on architectural expression and the spaces we design. Successful design, engineering, and production of building envelopes require integration across disciplines. The building envelope has an unparalleled impact on the perceived qualities of architecture – in terms of both aesthetics and performance. Besides performance and aesthetics the building envelope represents very considerable risks in terms of all of the things that can go wrong and delay the construction and/or lead to costly problems during the in-service life of the building. The value of assets is affected significantly by the building envelope and so its durability is of paramount importance to owners of building portfolios and owner-occupiers.

Facade Engineering is a term covering the specialist field, which bridges across more conventional disciplines and potentially both overlaps and integrates them. The successful integration in sector such as the construction industry is a big ask by any standard, but as benchmarks are changing the disciplines are forced to wake up and smell the coffee. The hope is that more people in our industry will recognise the importance of facade engineering as a means of delivering integrated design, more young professionals will see a possible career in this exciting field, and more clients will come to expect and begin to request – as a matter of course – that accredited professionals work on the delivery of their projects.