According to Chris Hall, chief executive at The British Rigid Urethane Foam Manufacturer’s Association (BRUFMA), the road to zero carbon has many hurdles, but the journey is a worthwhile one, even if it seems at times like there are a few too many obstacles along the way
It is a given that buildings are large contributors to carbon dioxide emissions. In the UK alone, buildings account for over 40 per cent of the total carbon emissions which makes housebuilding a key sector where carbon reductions can be addressed. Despite the coalition government watering down legislation requiring all new houses to be zero carbon from 2016, how do housebuilders come to terms with the challenges of addressing the CO2 performance gap between the designed performance of new build homes and what they can achieve in practice? What part will high performance insulation have in helping to achieve this ambitious target?
The Zero Carbon Hub released two publications in March and July 2014 that gives some indicators of how we might “close” the performance gap of “as designed versus as built.” Unless we close that gap, zero carbon will continue to elude us.
The industry recognises that there is huge potential to innovate, improve best practices and reduce carbon emissions in a positive and cost-effective way. But to change the way homes are built long into the future, a new precedent must be set and this starts and ends with the fabric.
A fabric first approach
External Fabric Insulation has quite a significant part to play in the achievement of the zero carbon goal, and high performance insulation materials with excellent thermal values, such as PIR/PUR, have much more of a role than many other insulation types. The combination of low conductivity, lightweight, and great strength has helped the industry gain a significant portion of the total insulation market. To specify a high performing insulation material, such as PIR, only to find that it might be less effective in use, is something that the industry must address and resolve. The steps appear simple, but this still seems to elude us.
It is incumbent on a number of stakeholders in the process to ensure that we get the value of the investment in the fabric insulation. The focus on changing building regulations for new build is a step in the right direction, but we must remember that the UK has significant legacy issues, with one of the poorest, if not the poorest, building stock in terms of energy efficiency. So achieving zero carbon for new construction, whilst laudable, is part of a wider issue that the UK needs to resolve, if we are to gain the kind of “energy security” most governments crave.
While the housebuilder might be the last in the new build chain, and have a significant part to play, they need assistance from others involved earlier in the process.
The designer must consider the correct detailing around junctions and other interruptions to the fabric, and when calculating U-values they should use accredited and credible software or services to give them an accurate picture of the U-values they are looking to achieve. The manufacturers of most insulation materials provide excellent services in both design assistance and calculations. Designers should only use materials that carry the appropriate certification and as simple as it sounds, look for evidence that the materials selected are readily available in the thickness specified.
Insulation manufacturers should provide products fully CE marked and compliant with the design specification, and importantly, provide clear and accurate information to the designer in the first instance. Moreover, they need to look constantly at product design and function, to make products that not only work on the drawing board, but also translate into effective in-situ performance. Clear instructions on installation should be provided within packaging or by some other form. Poor installation can be partially tackled by adequate and clear instructions.
Manufacturers must find an effective way to interface with training establishments, so that new and existing installers can be instructed in how to use insulation materials to get the best results. Many of the high performance insulation specialists also have mobile dedicated site support services to assist. Product availability does hold the key as unavailable product leads to ad hoc changes in specification that can have unintended and unfortunate consequences in fabric performance. Manufacturers must have adequate distribution channels.
Contractors should ensure that if they choose to change an insulation specification, they seek solid impartial advice on any changes to ensure they are not compromising the fabric thermal performance. Competency in installation is vital because when a high performing product such as PIR/PUR is installed incorrectly, it will compromise that performance. The contractor needs to make sure that not only the levels of site supervision are of a good standard, but the manufacturer’s installation instructions are followed and installation instructions around potential cold bridges and awkward details are followed.
While most of the above might appear to be axiomatic, it is often far from evidenced in reality. It is a supply chain challenge, and one that most likely will only be solved by all in that chain “doing their bit” to deliver on that elusive zero carbon goal.
Many insulation manufacturers are playing their part and are fully committed to support- ing the journey towards zero carbon. This is evidenced at both the individual company and at the trade body level, where initiatives, such as good practice guides and practical advice are available to all stakeholders to ensure that when PIR/PUR materials are used the theoretical performance is translated into reality on site.
The ‘fabric first’ approach will ultimately bring us closer to Zero Carbon compliance with energy performance requirements of Building Regulations, so if a structure is built correctly in the first place it will continue to perform as intended for years to come.