PVC-U windows and doors. An environmental overview

Transcription

1 PVC-U windows and doors n environmental overview

2 Introduction Concern for the environment is increasing and it is right that construction materials manufacturers give details of the environmental impact of their products to assist the specifier or purchaser in selecting the best product for the job over all. This brochure aims to give a summary of that information for PVC-U windows and doors and provide details of where further information can be obtained. More information is also available from Green Guide to Specification and Reference service life The Building Research Establishment, BRE 1, when updating and revising their Green Guide to Specification, were commissioned to undertake a Scoping Study 2 to review their reference service life of PVC-U windows now that more real life UK experience was available. Their report in March 2006 concluded that PVC-U windows should have a reference service life of at least 35 years. This figure was used in the revision to the Green Guide which was finalised and made publicly available 3 on 6 th June s can be seen from the table, no material wins in all categories. ll have better performance in some areas than others, as could be reasonably expected. With an rating for domestic windows and an + for commercial, there is no reason for PVC-U windows not to be used on environmental grounds. The BRE Green Guide web site emphasises that windows should be chosen to reduce operational energy usage. The main environmental impact of windows is from the heat loss through them. ttention is drawn to the large number of credits available in BREEM, the Code for Sustainable Homes and EcoHomes for reducing fabric heat loss and improving operational CO 2 emissions compared to the small number available for materials specification. The embodied impact of windows should only be taken into account as a small part of the decision, with the main emphasis being to choose a window which will reduce operational energy usage. Windows are one of the elements with a less important role in the overall embodied impact of buildings due to their low impacts and low area within buildings.

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4 Green Guide data comparison table for windows and cladding Element PVC-U window with steel reinforcemen t, double glazed Preservativ e pretreated softwood window, double glazed, water based stain Preservativ e pretreated softwood window, doubled glazed, solvent borne gloss paint (TWS) Powder coated galvanise d hot rolled steel window, double glazed Powder coated aluminiu m window with softwood internal frame, double glazed, water based stain internally PVC weatherboardin g on timber battens, insulation, lightweight blockwork wall, plasterboard, paint Canadian Western Red Cedar cladding on timber battens, insulation, medium dense blockwork, plasterboar d, paint Summary rating commercial + Non-TWS Non-TWS TWS + B E + + Summary rating domestic Non-TWS TWS + Non-TWS TWS + B E + + Domestic window impact categories Climate change Water extraction Mineral resource depletion Stratospheric ozone depletion Human toxicity D D E + E B C C E B + + B E E + B E + + Ecotoxicity E + + Nuclear waste B C C + E + Ecotoxicity to land Waste disposal Fossil fuel depletion Eutrophicatio n Photochemic al ozone creation E + + C E E E B + + E B + C + D D + E C E cidification + + E

5 The material Polyvinyl chloride (PVC) is a major thermoplastic material finding use in a very wide variety of applications and products. The essential raw materials for PVC are derived from salt and oil. The electrolysis of salt water produces chlorine, which is combined with ethylene, obtained from oil, to form vinyl chloride monomer (VCM). Molecules of VCM are polymerised to form PVC resin, to which appropriate additives are incorporated to make a customised PVC compound. There have been concerns voiced about PVC, its constituent parts and the by-products of manufacture. Concerns centre on the use of non-renewable fossil fuels, the chlorine content of PVC-U and the production of dioxins during manufacture. Fossil fuel content - The fossil fuel content of PVC-U is approximately 43%. When oil is refined it can yield a number of useful chemicals, one of which is ethylene the chemical used in the manufacture of PVC. Some have claimed that it takes eight tonnes of oil to make one tonne of PVC, the inference being that the remainder is wasted. Obviously this is untrue. Chlorine - The non fossil fuel derived content of PVC (approximately 57%) is predominately chlorine, derived from salt (Sodium Chloride), one of the most common materials in the earth s crust. Reserves of salt are estimated at 53 quadrillion tonnes, enough to form a crust around the earth 40 m thick. Obviously we are unlikely to run out any time soon. Dioxins - Some have expressed concern about the dioxins that are released during the manufacture of PVC resin. Minute quantities are indeed produced. However, those dioxins are almost exclusively retained within the pipe work of the manufacturing plant. They are removed under carefully controlled conditions and destroyed in special high temperature incinerators. In fact that industry is strictly regulated - the highest concentration of dioxins allowed for industrial discharges is 0.1ng/cubic metre of emission. report carried out in France in 2003 discovered that dioxin concentration in the vicinity of a standard BBQ has been measured at 0.7ng/cubic metre, seven times the industrial concentration limit. The conclusion must be that stopping PVC production would have a negligible effect on dioxin levels. Major manufacturer of PVC resin carefully monitor their dioxin emissions. They are typically mg TEQ per year (milligrams per year measured). The engine on a tug boat emits around 70mg TEQ per year. More information on the manufacture of PVC is available from the BPF. 4 Vinyl 2010 Vinyl is the ten-year voluntary programme on Sustainable Development by the whole PVC industry. We have a concrete focus as set out in the European PVC Industry's Voluntary Commitment - a series of targets, projects, initiatives and research studies primarily concerning environmental protection and resource management. To our knowledge, the programme is unique in Europe or elsewhere. In 2000, the European PVC industry started a 10-year plan to enhance sustainability of its product and production over the full lifecycle. This means relentlessly improving production processes and products, investing in technology, minimising emissions and waste and boosting collection and recycling. The programme is based on the Voluntary Commitment' signed by Vinyl 2010's four member associations 6. fter publication, the Commitment received a wide range of comments during extensive public and political consultations, including from the European Commission's Directorate General

6 Environment and Directorate General Enterprise. These led, in 2001, to a revised and expanded document. The main commitments are: Compliance with ECVM Charters on PVC production standards. plan for full replacement of lead stabilisers by 2015, in addition to the replacement of cadmium stabilisers that was achieved in March The recycling by end 2010 of 200,000 tonnes/year of post-consumer PVC waste The recycling of 50% of the collectable available PVC waste for windows profiles, pipes, fittings and roofing membranes in 2005, and flooring in n R&D research and development programme on new recycling and recovery technologies, including feedstock recycling and solvent-based technology. The implementation of a social charter signed with the European Mine, Chemical and Energy Worker's Federation (EMCEF) to develop social dialogue, training, health, safety and environmental standards, including transfer to EU accession countries. Before publication the reports are audited externally by specialists KPMG and Det Norske Veritas and approved by our independent Monitoring Committee composed of representatives from the European institutions, trade unions, academia and industry. The Vinyl 2010 website gives details about the progress being made. Materials for recycling Waste materials generally fall into 4 categories. Extruder scrap, fabricator off cuts, short life windows and doors (Manufacturing errors, damaged frames, etc.), and long life windows and doors (windows and doors that have been installed and subsequently removed). Extruder scrap is re-used in-house and over 99% of material generally ends as up as useful product. Over 30,000 tonnes of off cuts from fabricators are already collected and recycled and there is a thriving and competitive market. Short and long life windows are increasingly entering the waste stream and to avoid these going to landfill, the PVC industry has set up an organisation, Recovinyl 7 to facilitate the collection and dismantling of the used windows and doors across Europe. In 2007, the UK recycled over 40,000 tonnes of used windows and doors. Recovinyl subsidises waste collectors to collect and separate out the used PVC products and then arranges independent auditors to check the amounts being recycled by recycling companies. Various techniques are used to separate out any contamination of the used PVC-U material before it is re-used in new products. Examples of the new products include, cavity closers, electrical conduits, rainwater goods and trims. The material can be used as the core of a co-extrusion for windows where the surfaces designed to be weathered are covered by a layer of new material. However, volumes are such that there is insufficient for manufacturers to be certain of a sufficient supply. PVC-U profiles can be recycled at least 8 times 8,9 while still maintaining performance levels giving a life of several hundred years.

7 Life cycle analyses PVC is one of the most researched and studied plastics and independent information on life cycle performance is widespread. The European Commission in pril 2004 commissioned a report 10 led by PE Europe, a respected LC into PVC and its principle competing materials in various applications, including windows. The overall goal of the study was to compile an overview of the publicly available information on Life Cycle ssessments (LC) on PVC and competing materials, for a variety of applications, in order to assess existing information and to identify information gaps. It stated : For windows, one of the most important PVC applications, the available studies conclude that there is no winner in terms of a preferable material since most of the studies conclude that none of the materials has an overall advantage for the standard impact categories. The most promising potential for lowering environmental impacts of windows is expected through the optimisation of the design. Therefore the choice of material is of rather minor importance, as long as the material can provide the required system quality of the window. By far the largest environmental effect is the in-use phase which the Green Guide does not take into account. PVC-U windows can assist is providing the highest energy performance in windows. The British Fenestration Rating Council (BFRC) Window Energy Rating (WER) uses the rainbow to G classification system to show individual widow systems benchmark performance. 11 Details of the U value, g value and air tightness are listed for all the windows for which WERs have been awarded. lthough the scheme is aimed at domestic replacement windows, the underlying information can be used in SP calculations. t the time of writing, over 90% of rated windows are PVC-U. By selecting high energy performance windows, home builders can use PVC-U windows to achieve their Dwelling Emission Rate and their level under the Code for Sustainable Homes 12. Summary Windows should be selected on their ability to reduce fabric heat loss PVC-U windows form the bulk of windows energy rated Band C or better PVC-U windows are available in a wide range of styles and finishes PVC-U windows are cost effective and offer genuine value for money PVC-U windows are low maintenance PVC-U is being recycled in large volumes PVC-U does not harm the environment Further reading WRP Research into waste glass, window and door frames from the demolition and replacement window industries 13 WRP R&D Report Materials and products from UK-sourced PVC-rich waste 14 WRP Recycling Your Window Waste a Good Practice Guide 15

8 GOOD PRCTICE GUIDE 1 BRE, 2 Scoping study service life estimation of PVC-U windows. Client report no The European Council of Vinyl Manufacturers (ECVM), The European Plastics Converters (EuPC), The European Council for Plasticisers and Intermediates (ECPI), The European Stabiliser Producers ssociation (ESP) Leadbitter J, Bradley J (1997) Closed Loop Recycling Opportunities for PVC. Institute of Polymer Technology and Materials Engineering, Loughborough University ; 3-4 Nov ' PE Europe GmbH Life Cycle ssessment of PVC and of principal competing materials