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The availability of documentation to support the sustainability claims of PVC.

After last month’s go at the Wood Windows Alliance’s, to say the least, confusing advertisement being scattered far and wide over the trade and specifier press it got me to thinking about just how much information is available on PVC as a material and its environmental performance. The Green Guide to Specification I wrote about last month is OK as far as it goes, but there is a ton of other material out there. Coincidentally, a BPF member asked for an environmental overview to satisfy the request of a specifier to a potential supplier for their environmental credentials. So it seemed apposite to actually draft something that would bring lots of information together. And before you think this is going to be a sales pitch, it’s not. The document will be free of charge in pdf format for downloading. Here’s a few of the topics covered in a little detail in the overview document which also contains links to more detailed documentation.

It is frequently claimed that PVC is the most researched plastic in the world. And, of course, it is not just windows that use PVC. There are hundreds of applications including such life-saving applications as blood bags and other perhaps less savoury uses in S and M dungeons, but there also nearly as many myths about PVC floating around. Polyvinyl chloride was discovered in the late 19th century so it has been round long enough, but it was in the 1930s that it really came into its own and was used to replace increasingly costly natural rubber.

The BPF have a number of documents about the PVC manufacturing process for those interested in delving a little deeper, giving facts on fossil fuel content, chlorine and dioxins. One of the prime distortions of PVC detractors is that it takes 8 tonnes of oil to produce 1 tonne of PVC with the implication that the other 7.5 tonnes is discarded. In fact ethylene, from which most PVC is made, is just one of many useful chemicals produced from oil. That 7.5 tonnes is put to good use. PVC is also in some areas in Brazil and India made from bio feedstock.

The fossil fuel content of PVC is approximately 43% with the other 57% coming from sodium chloride, common salt. It is said that there is enough salt dissolved in the world’s oceans to cover the whole planet to a depth of 40 metres, so salt rationing is not on the horizon just yet.

Another claim by detractors is that PVC plants are “dioxin factories”. Yeah, right. All industry, not just PVC plants, is strictly regulated for dioxin emissions. Minute amounts are produced during the manufacture of PVC and these are virtually all retained within the manufacturing plant to be removed later and destroyed in special incinerators. The thought that current European law would permit dangerous manufacturing processes, “dioxin factories”, in this day and age is almost laughable. The highest concentration of dioxins allowed for any industrial discharges is 0.1 ng/cubic metre of emission. A report carried out in France in 2003 discovered that dioxin concentration in the vicinity of a barbecue cooking meat was 7 times the legal limit for factories. Certainly made me look sideways at the burnt offerings in my back garden and wonder whether I am giving all my friends (two at the last count) something more than the traditional beer and food poisoning. And we haven’t even mentioned bonfire night when all that organic material is burnt producing dioxins galore.

Manufacturing processes improve with time and the environmental impact of the manufacture of PVC is reducing. The industry has a commitment (Vinyl 2010) to continue this reduction as well improving the recycling rates. There is an R&D programme on new recycling and recovery technologies. The progress of this commitment is independently audited by specialists KPMG and Det Norske Veritas. Annual reports are available.

Recycling rates of used PVC are increasing year on year and the UK window industry is the star performer in this respect. Recycling in the UK is under the auspices of Recovinyl and is again, independently audited. There is a competitive market in the collection and recycling of off-cuts and any company binning these, and, incredibly, I have heard of one or two, is throwing money away. Recovinyl subsidises the collection and recycling of used PVC-U windows but these subsidies are reducing year on year as infrastructure is brought on-line, recycling techniques improve and the business becomes financially self-supporting. Research has shown that PVC can be recycled a number of times without deterioration of performance potentially enabling the material to be used for hundreds of years.

By Paul Jervis

Paul Jervis is a leading PVC-U industry expert and Technical Consultant to the British Plastics Federation (BPF). Visit www.pauljervis.net