Poison plastics: do you know what's under the lid?
While EU legislation has long banned the use of halogens such as polybrominated biphenyl (PBB) and polybromilated diphenyl ether (PBDE) as flame retardants in plastics and other products, the halogen problem is a long way from being over. Chris Lloyd, of Spelsberg els UK discusses some of the issues and dangers that all specifiers of enclosures should be aware of.
Every year, in Europe alone, fire leaves more than 4,500 people dead and 40,000 severely injured, with economic damage estimated to cost €25 billion. We can see, then, the importance of effective fire retardants to inhibit the combustion process. The flame retardants themselves, though, have come under increasing scrutiny in recent years, with growing concerns over the impact of these chemicals on health and the environment. The earliest flame retardants, polychlorinated biphenyls (PCBs) were banned in 1977 when it was discovered that they were toxic. Industries shifted to using brominated flame retardants, most notably polybrominated biphenyl (BPP) and polybrominated diphenyl ether (PBDE), but these, too, were found to be extremely harmful.
Bromine is one of the halogen family of elements in group VII of the periodic table, which includes fluorine, iodine, chlorine and astatine - all naturally occurring elements, frequently combined with other elements to form the salts group. But halides, when they burn, release highly toxic dioxins, a group of chemicals known to increase the likelihood of cancer, as well as increasing the likelihood of reproductive, developmental and immune problems. And they cause problems with recyclability.
At their peak, bromine based flame retardants were applied to 2.5 million tons of polymers annually, with the annual consumption of PBDEs being in excess of 40,000 metric tons. Research in Sweden from the late 1990s revealed that PBDEs were accumulating in breast milk, while studies in the USA showed that nearly all Americans tested had trace levels of flame retardants in their bodies. Action had to be taken, and in the EU the introduction of the RoHS regulations and the WEEE directive banned the use of these most commonly used flame retardants.
Fortunately from a fire prevention sense, new formulations of plastics were quickly brought to market that offered effective flame retardant properties without the use of harmful halogens. As an example, the halogen-free duraplastic used within Spelsberg's WK series enclosures can withstand temperatures up to 700°C, does not burn after UL 94 V-0, and is glow wire proof to VDE 0471.
Prevalence of PVC
So have we seen the end of the halogen problem? Unfortunately, these hazardous compounds are still very much a feature of our daily lives, most notably in polyvinyl chloride, or PVC as it is better known. Second only to polyethylene in the prevalence of its use in plastics production and consumption, PVC is used in an enormous range of consumer and industrial products, many of which tend to have short service lifespans, exacerbating the problem. Vinyl chloride is one of the most toxic of the halides. The circulatory, nervous and immune systems can all be affected, with exposure over a long duration leading to the development of a number of life-threatening diseases, including liver cancer, brain cancer, lung cancer and angiosarcoma.
PVC causes health and environmental problems throughout its lifecycle, from manufacturing through consumption to disposal. The production of PVC requires the use of highly polluting chlorine and cancer-causing vinyl chloride monomer (VCM). The best efforts of manufacturers do not seem to be able to contain these compounds: residents of the town of Mossville, Louisiana, USA which hosts a vinyl chloride chemical facility were found to have levels of dioxins in their blood that were three times higher than normal.
In product use, dioxins can bleed into the atmosphere from PVC products as they are broken down by UV light, building the potential for health problems. And then there are the dioxin emissions from the millions of annual fires that burn buildings, vehicles and consumer products - all major applications for PVC. But it is perhaps in the disposal of these products where the problems really accumulate. PVC disposal represents the largest source of dioxin-forming chlorine.
PVC is difficult to recycle: because there are so many different formulations of PVC, there is no generic process to separate the PVC into its original formulation for recycling. And when PVC products are mixed with the recycling of non-chlorinated plastics, they contaminate the entire recycling process. Introducing just one PVC bottle into the recycling process could contaminate 100,000 bottles, rendering the entire plastics stock unusable.
PVCs in landfill
Incineration is no solution, since burning forms dioxins that are released into the air or disposed of on land as ash. As a result, most PVC products end up in landfill. At this point, many of the other chemicals and additives used in the manufacture of PVC find their way into the environment causing further contamination.
Governments and industry are taking action to eliminate PVC. The Danish and Swedish governments are restricting PVC use, hundreds of communities worldwide are eliminating PVC in buildings, and leading companies have committed to eliminating PVC from their products. Spelsberg is among them, building its market leadings ranges of enclosures from plastics such as polyethylene, polypropylene, polycarbonate and polystyrene. The cost and performance of these alternative compounds all but eliminates the need for PVC, completely removing health risks while dramatically improving the overall recyclability at the end of life of products.
With plastics so diverse in their applications and so prevalent in our daily lives, the regulations that control their use are becoming steadily tighter, focusing on air quality, end-of-life, toxic substances and fire safety. For PVC, a tightening of the regulations surely cannot come fast enough. For its part, Spelsberg is committed to a PVC-free environment, and is confident in its ability to meet any user application requirement for enclosures with any of a number of other innovative, high performance, cost effective, and completely safe compounds.
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