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Standards Extra Perimeter sealing of doors and windows In this article we look at the perimeter sealing of windows, doors, other openings and interfaces. The three key factors that will ensure maximum performance and durability of the installation are weathertightness, airtightness and insulation. All of these must be fully considered at design stage. How is a good quality airtight seal achieved? By using a membrane capable of accommodating movement (i.e. it has to be flexible) after installation. Proprietary products are available with inbuilt flexible folds for movements and pre-applied adhesive strips to bond the membrane to the window and structure. How is an external weathertight seal achieved? Whilst good quality silicone and other wet sealants may provide adequate performance, the use of impregnated foam tapes also provide (at a minimum of 600 Pascals) good long term life expectancy as well as the ability to cope with significant movement and wide joint size tolerance. Impregnated foam also offers breathability allowing any moisture behind the seal to dissipate to the exterior of the building. A range of quality sealants are available and installation should be carried out in ACTION accordance with the BASA (British Adhesive and Sealants Association) Industry Guide to Professional Application of Construction Sealants on Site. How can the thermal performance of the window frame/structure connection be enhanced? Gun applied air tight PU foams are available with high levels of movement accommodation. However, enhanced impregnated foams have been developed that provide the three required levels of sealing (airtightness, weathertightness and insulation) in one application. Ensure that appropriate seals and sealants are correctly specified and installed to achieve maximum in-service performance. ACTION Microgeneration Certification Scheme (MCS) publishes guide for installers Towards the end of April MCS published a guide entitled ‘Low and zero carbon technologies: opportunities and the MCS’. The guide is for installers of renewable energy systems on the MCS quality assurance scheme. The guide is available as a free download from http://www. microgenerationcertification.org/ docs/Opportunities-and-the-MCS_ web.pdf. BBA issues certificates for renewable energy systems Earlier in the year the British Board of Agrément issued its first two MCS Certificates. These were the result of a certification process set out in the Microgeneration Certification Scheme (MCS). The two products are: • Clearline Solar Collector from Viridian Solar (Certificate 0001) • TopSola TSM-160M Solar Photovoltaic Modules from MAP Environmental (Certificate 0002) NHBC will soon be looking for renewable energy system products and their installation to be covered by the MCS scheme. If your house designs are incorporating renewable energy systems or you have an installer who is not currently covered by MCS and would like to know more then please pass this information on. 8
Issue 47 June 2010 Contaminated Land - New Soil Guideline Values Soil Guideline Values (SGV’s) were originally introduced by DEFRA in March 2002 for a range of contaminants that may be found in the ground on brownfield land or previously developed sites. The SGV’s were specifically developed for use in assessing the risk to human health from contamination in soils as part of the Contaminated Land Exposure Assessment (CLEA) framework for use in the UK. The CLEA framework and SGV’s were developed to provide authoritative guidance in support of the implementation of Part 2A of the Environmental Protection Act 1990 that laid down the new regulatory role for Local Authorities dealing with land contaminated and also to provide a more robust and scientific method of assessment to replace the previous guidance: 1987 ICRCL (Interdepartmental Committee on the Redevelopment of Contaminated Land) recommendations for action and trigger levels for contaminants in soils. However, since the original publication in 2002 further detailed scientific reviews together with extensive consultations with stakeholders in the contaminated land industry have resulted in a number of fundamental revisions to the contaminated land framework and the model known as CLEA UK used to produce SGV’s. As a result, in July 2008, the 2002 SGV’s were withdrawn as they no longer reflected the updated UK approach to human health risk assessments. From late spring 2009, new SGV’s have been produced and published for a variety of contaminants using an updated framework and model now known as CLEA 1.06. These revised SGV’s are recognised in the UK as being authoritative and scientific. They should be used as a tool to aid the evaluation of whether a concentration of a contaminant in near surface soils is ‘acceptable’ in the assessment of long term risks to human health for various land uses including residential. SGV’s are intended only to assess long term risks to human health from contaminants in soils and they do not take into account other issues such as: • Risks for short term exposure • Other types of risk to humans, such as fire, suffocation and explosion • Non-human receptors, for instance ecological, controlled waters, property, domestic produce or domestic pets • Contaminant sources arising from and to controlled waters (ground water) • Free phase products in soils or groundwater beneath the site (e.g. hydrocarbons such as oils, diesel, petrol). DEFRA has an ongoing programme for publishing SGV’s for potential contaminants in soils and during 2009 values have been released for the following; Benzene, Toluene, Ethylbenzane, Xylene (Hydrocarbon), ACTION Mercury, Selenium, Arsenic, Nickel, Phenol, Cadmium and Dioxin’s including PCB’s. When assessing contamination on a site, representative site soil concentrations at or below an SGV indicate that it is unlikely that there is a significant possibility of harm to human health and the site can be considered safe for development. When concentrations exceed an SGV, there may be a potential risk to human health and further risk assessment is required to determine whether remediation is necessary. Due to the complex nature of contamination, it is recommended by the NHBC that a suitably qualified person/consultant should always be used to investigate the site, assess the risks and develop any remediation strategy as necessary. 9
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Page 3 and 4: Issue 47 June 2010 Glassfibre Reinf
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Page 7 and 8: Sustainability 7 Extra June 2010 Mi
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