Operational energy efficiency

Dr Justin Furness, CAB technical director, discusses why aluminium is an energy-efficient option and outlines the role of the Aluminium Stewardship Initiative (ASI) in responsible sourcing.

The need for investment in energy efficient buildings has featured in several of the political manifestos during the recent general election campaign and also in a number of recent reports and initiatives that have highlighted the potential

benefits of installing energy efficient glazing, as well as the complex nature of the issue. The building sector in Europe is responsible for more than one third of the energy consumption and a similar share of the CO2 emissions associated with human activities. Meanwhile Britain has some of the oldest housing stock in the world; it is thought that more than 8.5 million British properties are over 60 years old. There is no question that something needs to be done.

The National Energy Foundation (NEF), with the support of the glazing supply chain (comprising: Glass and Glazing Federation (GGF), British Glass (BG), Flat Glass Manufacturers Association (FGMA), Steel Window Association (SWA), Council for Aluminium in Building (CAB) and European Window Film Association (EWFA)), has recently reported on the operational energy reduction potential in the existing building stock, driven by accelerated uptake of energy efficient glazing (see www.glazingsupplychaingroup.co.uk). The study looked at several scenarios and even assuming a relatively modest increase in the uptake of enhanced glazing products, by 2050 energy consumption during the heating season could be some 15,000 GWh lower compared with maintaining the current rates of renewal. To put this in context, it is roughly equivalent to the energy generated by two Sizewell B nuclear power stations. It was also estimated that another Sizewell B nuclear power station could be saved if energy leakage around windows could be reduced through improved installation practices. It is therefore crucial that we adopt a more holistic approach to buildings, considering the interaction between the components, the building, the occupants and the climate, and how they are all put together.

While efforts to stimulate the retrofitting of energy efficient glazing in existing buildings continue, the government has recently announced that it is dropping the zero carbon targets for new buildings, along with the Allowable Solutions carbon offsetting scheme. This should help drive up the number of houses built and improve the UK’s productivity, arguably two critical metrics for a developed economy, as well as allow more time to evaluate the impact of current regulations. We therefore take this opportunity to spread the message that energy efficiency is not restricted to consideration of the heating season only (in the UK) and that it cannot be regulated in isolation from other parameters that directly affect energy usage and occupant comfort. The industry, including architects, product manufacturers, fabricators and installers, has a difficult balancing act to strike when it comes to glazing in particular, and we must work together more to address this. For example, it is common sense that the size and orientation of glazing are important factors when it comes to making this balance.

Building Performance Institute Europe (BPIE) has recently carried out a review of residential building regulations in eight EU Member States (http://bpie.eu/indoor.html). This report stresses the importance of having appropriate requirements for thermal comfort, ventilation and daylight conditions. All told, we spend some 60-90 per cent of our time indoors, so indoor air quality plays a vital role in our health and wellbeing. Improving the air tightness of buildings is again identified as an important factor, as well as the need for ventilation control and air exchange. Our target in this regard as an industry is now set out in the EU’s Energy Performance of Buildings Directive, under which the UK has to deliver nearly zero energy buildings from 2021 (and from 2019 in the public sector). Will it be possible for building regulations to evolve from requirements for energy performance to requirements that also ensure a holistic approach to thermal comfort, indoor air quality and daylighting?

Whichever direction the regulations take, aluminium remains a smart choice for the framing material, offering, for example: narrow sight-lines thereby maximising daylight and access to surrounding views, thermally broken profiles thereby reducing heat loss, sections with exceptional strength to weight ratios thereby allowing large glazing areas, and a wide range of configurations, from the bi-fold to the tilt and turn. It is also the responsible choice, with exceptional durability characteristics and recycling rates of over 90 per cent.

Cradle to cradle efficiency

Responsible sourcing is becoming increasingly important in the construction sector and rightly so. No manufacturer that values its reputation would want to be associated with corruption or with needlessly wasting precious resources, for example. This is, however, another area where one size does not fit all and several sourcing issues are harder to measure in some sectors than others and are not readily comparable. The value chain for

a material that can be mined, manufactured and installed locally, for example, will be very different compared with that for a globally traded commodity, such as aluminium.

To address this, several organisations involved in the aluminium value chain have been part of the Aluminium Stewardship Initiative (ASI), which was launched at the end of 2012 (http://aluminium-stewardship.org). Part 1 of the ASI Performance Standard was published in December 2014 and it sets out the environmental, social and governance principles and criteria applicable to the aluminium value chain. Relevant measures for each criterion and the means of verification are in development.

One of the most important principles that the standard sets out is that of materials stewardship, highlighting the need to evaluate life cycle impacts and to promote resource efficiency and the collection and recycling of aluminium.To complement this, ASI has also drafted a Chain of Custody Standard which sets out that, at each stage in the aluminium value chain, materials from ASI-compliant sources are properly managed and only mixed under controlled procedures with materials from sources that meet ASI minimum requirements, and not mixed at all with materials that fall short of the ASI minimum requirements, with these latter materials eliminated from the supply chain.

We will be working with our members over the coming months to evaluate how we could implement the ASI Performance and Chain of Custody Standards in our part of the aluminium value chain, as well as how it matches up against the requirements of BS 8902 (Responsible sourcing sector certification schemes for construction products) and BREEAM in particular.