MMA Yearbook 2007 21 types of developments, it allows on-thespot changes to be made as the building process continues. With Aircrete there are very few design limitations and designers and developers are able to create almost any size, shape or living environment without compromise in terms of cost and technical ability. Aircrete products are available in a range of sizes and densities so that a huge variety of buildings can be created from small bungalows to town houses, flats and apartments. It is also totally suitable for a number of applications within commercial buildings, which are increasingly becoming a feature of many housing schemes. Aircrete can be drilled, cut and chased using ordinary hand tools, making it easier for bricklayers and finishing trades alike. Its flexibility allows overall build rates to be varied in order to match market demand. Acoustic performance From the APA’s perspective, this is an area where Aircrete’s efficiency needs to be continually conveyed to the industry, as sound insulation becomes more and more important with the number of apartments, flats and linked developments increasing. Although of a lower mass than many other masonry materials, Aircrete is able to provide excellent acoustic insulation due to its unique composition. The cellular structure of Aircrete breaks up the passage of sound waves making it the perfect material for sound insulation for internal and external walls, separating walls, as well as internal and separating floors. Planning and management Managing a development utilising Aircrete is far easier for a number of reasons. Lead-in and planning times are significantly reduced, as there are no constraints of a pre-ordered frame design. Detailing of brick and block interfaces are well known and can even be decided on as the development progresses. Many builders consider the management and natural progression of different trade teams on site as much easier when building with Aircrete. Despite all the criticism of our building industry, the process of house building with masonry materials is well known and tried and tested. However, Aircrete’s diversity, particularly with the addition of thin layer systems, ensures that known materials and building performance can utilise modern approaches to the build process to improve build speed and quality. Website focus As extensive as the list of Aircrete advantages is, they don’t mean anything unless they are properly conveyed to the target market. The new-look APA website is the key delivery mechanism for Aircrete product information. A series of brochures called ‘Building Blocks’ – which cover the five issues raised in the research by the home builders in more detail – is currently being developed and will be available to download from the website along with other literature outlining the advantages of building with Aircrete. Visitors to the website can also register to receive regular updates. The APA markets Aircrete as a ‘modern construction method’, which can compete with, and in many cases out-performs more recently developed build materials and methods. As far as we at the APA are concerned, our efforts now will serve not only to confirm Aircrete’s status as one of the best building materials in the market, but more significantly go a long way to ensuring that it is carried forward to meet the demands of the future. . Reader enquiries to: loretta.simpson@britishprecast.org

22 MMA Yearbook 2007 With a UK roll-out of revised Building Regulations for the conservation of fuel and power, a different approach is now necessary to achieve compliance. Energy requirement Revised Building Regulations for the conservation of fuel and power came into effect in England and Wales on the 6 April 2006. Similar provisions are expected to be implemented in November 2006 for Northern Ireland, and in May 2007 for Scotland. While successive changes to this part of the Building Regulations have been getting steadily more complex, this change differs significantly in approach and compliance is now based on overall CO2 emissions from buildings. This replaces previous routes to compliance such as the Elemental and Target U-value methods. The new regulations thereby implement part of the EU Energy Performance of Buildings Directive (EPBD), which all EU member states have to adopt. Compliance with the CO2 emissions targets is calculated according to SAP 2005 for dwellings, and SBEM for buildings other than dwellings (and for certain larger dwellings). These calculation methodologies take into account factors such as the insulation levels of individual building elements, building air-tightness and the efficiency of heating systems and heating controls. The detailed requirements for England and Wales are covered in four approved documents, L1A (new dwellings), L1B (existing dwellings), L2A (new buildings other than dwellings) and L2B (existing buildings other than dwellings). In Northern Ireland, Technical Booklet F1 will cover dwellings and Technical Booklet F2 will cover buildings other than dwellings. In Scotland, Section 6 of the Scottish Standards Technical Handbooks will cover the new energy requirements. Criteria for compliance of dwellings in England/Wales Five criteria have to be met to demonstrate compliance with the Regulations for England and Wales. 1. Check that the predicted rate of CO2 emissions from the dwelling, known as the Dwelling Emissions Rate (DER) is not greater than the Target Emissions Rate (TER). To obtain the TER, a calculation using SAP 2005 has to be carried out on a so called ‘notional dwelling’ of the same shape and size as the proposed dwelling. This calculation is carried out using the 2002 elemental U values. The CO2 emissions value so derived is then reduced by 20% to obtain the TER. 2. The dwelling fabric elements and fixed services should have performance values no worse than specified design limits. 3. The dwelling should have passive control measures to ensure that solar gains do not lead to high internal temperatures in summer. 4. The performance of the dwelling as-built should be consistent with the DER. For this to be ascertained, five sub-stages are involved: . Quality of construction and correct commissioning: If any assumptions made at the design stage are not carried through to the final construction, the SAP calculation needs to be repeated and the as-built DER calculated and compared with the TER limit. . Building services: A competent person needs to attest that the building and its services have been inspected, tested and commissioned and that they accord with the proposed building design. . Construction details: Site checking is required to confirm that the installation of the insulation has been carried out satisfactorily, to minimise thermal bridging. . Air permeability: A test has to be carried out to show that the design air permeability has been achieved, and that the permeability does not exceed the 10m3/(h.m2) at 50Pa limit. Reduced testing frequencies are permitted for larger sites where the same dwelling type is being constructed. . Calculating the as-built DER: Once all the as-built information is to hand, the DER should be recalculated to check that the built dwelling complies with the design TER. The second DER calculation needs to take account of the actual construction and services used and the measured air permeability. The heating and hot water systems are then commissioned and a notice is issued to Building Control by a competent person. 5. Information concerning the energy efficient operation of the dwelling has to be provided to the occupier. This will include sets of operating instructions that the occupier can understand. This information is expected to be included in the ‘Home Information Pack’. In Northern Ireland, the provisions in the new Regulations are expected to be largely the same as in England and Wales. For Scotland, a less complicated approach is proposed for dwellings, which does not involve a procedure to derive a TER from previous regulatory requirements. Instead, a schedule of notional buildings provided, one for each fuel type. If a dwelling is constructed to be at least as good as one of these notional building specifications, then no calculations are necessary. If one aspect of specification is not met then a calculation to SAP 2005 will be required to demonstrate compliance. While the simpler approach proposed for Scotland will not necessarily suit every application, its simplicity will make life much easier for designers to prepare their submissions for Building Control, and for Building Control to check and approve submissions. In turn, this should lead to a “The new aspects of Building Regulations relating to energy are very complex, but masonry is more than a match for the task.”