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Plastic fantastic?

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Last year, the Irish Architectural News reported that An Taisce, the National Trust for Ireland, had complained to Dublin City Council that PVCu windows were being installed in a listed Green Party headquarters building in Temple Bar. Despite the fact that it was the landlord, and not the 'highly embarrassed' Greens, who was installing the hated windows, here was a hilarious metaphor for the confusion surrounding PVCu windows. It is a confusion fuelled by the timber industry (supported, hint the PVCu people darkly, by forest interests abroad), by the conservative heritage protection industry and by the plastics industry. Taking the independent position is the odd television estate-agent programme, one of which recently claimed that PVCu windows knocked ú12,500 from the average selling price of a house.

An Taisce, which is the sole statutory planning consultee in the Irish Republic, recently won an appeal against the installation of PVCu windows in a local pub and announced that with this success behind it the organisation could now concentrate on courthouses and town halls. An Taisce heritage officer Ian Lumley points out that breaches of planning rules, such as installing PVCu windows, would be taken to court. 'But, ' he says, 'you'd go into a courthouse and there in the very courthouse were the wretched things.' He points out that in some areas of Ireland, things are improving. It has to be said that the heritage industry has a perfectly reasonable point, that in refurbishing designated historic buildings you really need to use the original materials and not attempt to fake the details by using substitutes.

History defeating Set aside for a moment the technical issues.

Opposition to the 'wretched things' often sounds like a mere snobby, knee-jerk reaction to the very idea of plastic: tacky, fake, cheap, flimsy, insubstantial - all those associations which you'd imagined had been wiped out by the oil price rise of 1973, and the consequent spiralling of the price of plastics. Not to mention the unobtrusive worming of plastics into our everyday lives, from car bumpers (an unlikely idea in 1973) through to children's toys, and house windows and doors.

As with other plastic products, early attempts at plastic windows were short on long-term performance, were crudely engineered and thus usually looked clumsy - and irretrievably white. As a Hull City Council guidance note says: 'PVCu windows, in particular, have crude parodies of authentic features such as glazing bars and non-traditional proportions.' Still, the same council guidance says: 'Designs of PVCu windows are improving all the time? and it is possible to get some replacement windows which replicate traditional designs much more closely.' Modern PVCu windows are engineered, which is to say they are reinforced with steel and sometimes timber, and have sections whose dimensions are around the same as timber windows. And they can be, though most architects are a bit shy of the fakery involved, faced with simulated timber foil.

Oddly enough, the modern timber window industry seems unable to produce off-thepeg windows that have the slender glazing bars of Victorian and Georgian off-the-peg timber windows.

Jersey takes a similar view for its historic buildings but admits that 'many replacement timber windows installed in recent years have been manufactured to such low standards that they deteriorate quickly. This has given timber windows a bad name? [but] if the timber is well selected, this is a more sustainable product than PVCu.' But there are surely technical reasons for avoiding PVCu. The guidance English Partnerships offers on plastic windows is that 'PVCu windows are discouraged because PVCu is a toxic material and has high embodied energy. There is also higher embodied energy in the steel core. Timberframed windows from accredited sources are much more preferable and generally perform as well as PVCu frames. Europe is now replete with sustainably produced timber from forests, which also benefits the environment when the wood is growing.' However, the English Partnerships guidance also points out that 'the inherent flexibility of the credits/points system within EcoHomes [the homes version of the BRE Environmental Assessment Method] enables PVCu to be used with compensating points achieved elsewhere.' The Green Register in Norfolk has a blanket down on PVCu windows. It says broadly that the manufacturing process is lengthy and produces toxic by-products, other chemicals are added, the final product does not biodegrade, additives leach in landfill, PVCu is hazardous when burned and the windows can't be repaired, and besides, timber is a renewable resource with low embodied energy and windows made from it can last for hundreds of years.

The London Borough of Lambeth says that in conservation areas 'materials such as PVCu windows are strongly discouraged'.

And a recent letter in the Guardian (9.6.04, p18) from North Shropshire conservation officer, Iain McCaig, claimed: 'PVC is arguably one of the most environmentally hazardous consumer materials ever produced? add to this? the fact that they can reduce the value of your property and the benefits of sticking to your old wooden ones are clear.' On the other hand, Leicester City Council is full of enthusiasm for PVCu replacement doors in its own council housing. They provide, says one of its blurbs to tenants who are getting new doors, 'a secure future, greater security, lower heating bills, fewer draughts, less decorating, and a choice of colours? red, burgundy, dark blue and white.' The council goes on to elaborate its detailed support for PVCu.

There is a down side, but it is not chemical - 'the doors are counted as an improvement to your home, so tenants are charged an extra 10 pence per door per week, ' says the council blurb.

Natural vs synthetic Not surprisingly, the British Plastics Federation (BPF) has been fighting back. It has the difficulty of the knee-jerk reaction: chemical equals bad, natural equals good. PVCu is made from synthetic chemicals and timber is a 'natural' material - although it too has to be processed and treated with synthetic chemicals in the form of preservatives, stains, paints and glue.

PVCu represents, says the BPF, 'a highly efficient conversion of raw materials: salt and oil derivatives combine to produce a plastic material that is specified for a broad range of applications'. One of the essential components of PVCu is chlorine, which is sometimes made using mercury. Stabilisers include metal salts and soaps. Window manufacturers are phasing out lead and have already eliminated cadmium. Off-cuts and factory waste are regularly recycled, and the industry is committed, by next year, to recycle half of the collectable available quantities of post-consumer PVCu window waste. Contrary to opposition claims, the BPF says that the incineration of PVCu need not present any special problems relating to emissions of dioxins. Modern incinerators in Europe are designed to meet stringent EU limits on the emission of a number of substances, including dioxins, and claims about landfill leaking nasties into the water table are simply wrong. A study by the Chalmers University of Technology in G÷teburg, Sweden, concluded that rigid PVCu does not degrade in landfill 'so that PVCu will remain inert and there is no evidence to suggest that PVCu would be a source of any toxic substances under landfill conditions'.

Who should we believe? Maybe we should all stick to aluminium, which can be easily melted down and re-extruded. Uh oh - but only by expending very high levels of energy, say its opponents.

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