Driven in part by legislative requirement and client’s desire to create sustainable and thermally efficient developments, building designers are carefully considering each material element of their designs. Here, Martin Saunders, Sales Director at Eurocell, takes a look at the different considerations when specifying windows.

“Windows have a major bearing on the sustainability and energy efficiency of buildings and there are many factors to consider when choosing them, including material, design, aspect and size. This is because carefully chosen windows can have a hugely positive effect on building occupiers. For example, studies have shown that maximising the amount of natural daylight within the building can have a beneficial effect on the wellbeing of occupants.

As sustainability becomes a central part of building design, choice of material for the window frame is also becoming a crucial consideration. We were recently involved on a residential healthcare project in Cheshire, where this decision was central to creating a sustainable development. The driving force for this was the fact that all new developments now have to meet Building Research Establishment Environmental Assessment Method (BREEAM) or Code for Sustainable Homes (CSH) standards. PVC-u windows can help achieve these requirements as the material has recently been awarded an ‘A’ rating for sustainability in residential and ‘A+’ for commercial developments in the BRE Green Guide to Specification (June 2008).

This is because material selection for BREEAM and CSH assessment methods is informed by the Green Guide to Specification. In effect, the Guide recommends the selection of environmentally sustainable materials. Increasing numbers of specifiers use it as the definitive information source on the subject, as was the case on the project in Cheshire. Already, we have received a number of enquiries from the commercial and residential sector in recognition of PVC-u’s environmental credentials and unbeatable value.

Coupled with this is the fact that PVC-u achieves a Reference Service Life (RSL) rating of at least 35 years, as recognised by the BRE, which confirms that cellular PVC-u products provide a cost effective, sustainable and durable solution to many sectors of the construction industry.

The principal reason for BRE awarding the top rating to PVC-u is because of the work that has gone into recycling across the industry. Last year alone, Eurocell recycled around 3,000 tonnes and we remain committed to re-using as much of our waste product in the manufacturing process as possible. Although a large part of our recycling activities are focused on our product and business operations, as a company we are looking at all avenues to improve sustainability. The latest of these is our acquisition of Merritt Plastics, which is a post-consumer PVC-u recycling and extrusion company. This is a huge benefit for public sector clients and contractors as it gives them a method of dealing with end-of-life PVC-u frames from site. We use this material to make our 100 per cent post-consumer waste recycled Cavalok cavity closer system. Cavity closers offer a faster and easier method of installing windows, whilst improving thermal efficiency and environmental performance of the building at the same time.

Closely linked to the sustainability of the windows is thermal performance. Here the Building Fenestration Rating Council’s (BFRC) A-G energy rating system – the UK’s national system for rating Energy Efficient Windows – has helped highlight the most efficient systems on the market. Over the last few years, we have developed BFRC ‘A’ rated window systems and many of our fabricators are now offering these to their customers. Although many developments choose energy rated windows, it is predominantly ‘B’ or ‘C’ rated that are specified because of the additional glazing cost of achieving an ‘A’ rating. This prompted us to develop a range of 100 per cent recycled PVC-u Thermal Inserts which improve the thermal performance of the window frame. This means our systems can achieve an ‘A’ rating without the need for more expensive low iron glass, providing all developments with a much better value for money ‘A’ rated window. As BREEAM and CSH requirements become more stringent with the move towards zero-carbon developments, it is initiatives like this that will help building specifiers achieve ‘A’ ratings most cost effectively.

Where a development is high-rise, specifiers often choose reversible windows to meet the requirements of Construction (Design and Management) Regulations 2007. The aim of CDM is the integration of health and safety into a building project by placing certain duties on local authorities, designers and contractors. For example, on high-rise developments, a building designer can reduce the safety risks and costs of ongoing maintenance and cleaning by specifying reversible windows. This is because the 180 degree rotating action of the sash allows the window to be cleaned from inside the building and therefore avoid the need for costly external access equipment during cleaning of upper floors.

Ironmongery, too, needs careful consideration. The windows on the Cheshire care home project had to be easy to open and close, as the designer was looking for a window that elderly or infirm residents could operate easily and comfortably. After studying the brief, we recommended the used of a top hung system as the handles are on the lower section of the opening sash. This has the advantage that they are therefore always within one metre of the floor – meeting the client’s brief and making them easier to open for residents. On other projects, tilt and turn hardware, in addition to providing safe ventilation, gives a single mechanism for opening, tilting and securely locking the window, which again offers residents much better ergonomic operation.

When considered in these various ways, windows have a significant role to play in good building design and not simply from a sustainability point of view. Windows should be an integral part of the development and although the decision on style, material and design may not be a straightforward one, when made with careful consideration a more comfortable, thermally efficient and sustainable building can be achieved. Ultimately, it is the residents that will benefit from more comfortable and user friendly accommodation and the fact that the building is more sustainable will mean lower running costs and a reduced carbon footprint for the owners.”

This entry was posted on Thursday, May 21st, 2009 at 1:42 pm and is filed under Environmental Stories, UPVC Profiles. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.