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ELECTRICAL EQUIPMENT & DESIGNEnclosures, Cabinets and FansPoison plastics: do youwhat’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 otherproducts, the halogen problem is a long way from being over. Chris Lloyd, of Spelsberg els UKdiscusses some of the issues and dangers that all specifiers of enclosures should be aware ofEvery year, in Europe alone, fire leaves more than4,500 people dead and 40,000 severely injured,with economic damage estimated to cost €25billion. We can see, then, the importance ofeffective fire retardants to inhibit the combustion process.The flame retardants themselves, though, have comeunder increasing scrutiny in recent years, with growingconcerns over the impact of these chemicals on healthand the environment. The earliest flame retardants,polychlorinated biphenyls (PCBs) were banned in 1977when it was discovered that they were toxic. Industriesshifted to using brominated flame retardants, mostnotably polybrominated biphenyl (BPP) andpolybrominated diphenyl ether (PBDE), but these, too,were found to be extremely harmful.Bromine is one of the halogen family of elements ingroup VII of the periodic table, which includes fluorine,iodine, chlorine and astatine – all naturally occurringelements, frequently combined with other elements toform the salts group. But halides, when they burn, releasehighly toxic dioxins, a group of chemicals known toincrease the likelihood of cancer, as well as increasing thelikelihood of reproductive, developmental and immuneproblems. And they cause problems with recyclability.At their peak, bromine based flame retardants wereapplied to 2.5 million tons of polymers annually, with theannual consumption of PBDEs being in excess of 40,000metric tons. Research in Sweden from the late 1990srevealed that PBDEs were accumulating in breast milk,while studies in the USA showed that nearly allAmericans tested had trace levels of flame retardants intheir bodies. Action had to be taken, and in the EU theintroduction of the RoHS regulations and the WEEEdirective banned the use of these most commonly usedflame retardants.Fortunately from a fire prevention sense, newformulations of plastics were quickly brought to marketthat offered effective flame retardant properties withoutthe use of harmful halogens. As an example, thehalogen-free duraplastic used within Spelsberg’s WKseries enclosures can withstand temperatures up to700°C, does not burn after UL 94 V-0, and is glow wireproof to VDE 0471.Prevalence of PVCSo have we seen the end of the halogen problem?Unfortunately, these hazardous compounds are still verymuch a feature of our daily lives, most notably in polyvinylchloride, or PVC as it is better known. Second only topolyethylene in the prevalence of its use in plasticsproduction and consumption, PVC is used in an enormousrange of consumer and industrial products, many ofwhich tend to have short service lifespans, exacerbatingthe problem. Vinyl chloride is one of the most toxic of thehalides. The circulatory, nervous and immune systemscan all be affected, with exposure over a long durationleading to the development of a number of life-threateningdiseases, including liver cancer, brain cancer, lung cancerand angiosarcoma.PVC causes health and environmental problemsthroughout its lifecycle, from manufacturing throughconsumption to disposal. The production of PVC requiresthe use of highly polluting chlorine and cancer-causingvinyl chloride monomer (VCM). The best efforts ofmanufacturers do not seem to be able to contain thesecompounds: residents of the town of Mossville, Louisiana,USA which hosts a vinyl chloride chemical facility werefound to have levels of dioxins in their blood that werethree times higher than normal.In product use, dioxins can bleed into the atmospherefrom PVC products as they are broken down by UV light,building the potential for health problems. And then thereare the dioxin emissions from the millions of annual firesthat burn buildings, vehicles and consumer products – allmajor applications for PVC. But it is perhaps in thedisposal of these products where the problems reallyaccumulate. PVC disposal represents the largest source ofdioxin-forming chlorine. PVC is difficult to recycle:20INDUSTRIAL TECHNOLOGY • November 2010
knowbecause there are so many different formulations of PVC,there is no generic process to separate the PVC into itsoriginal formulation for recycling. And when PVC productsare mixed with the recycling of non-chlorinated plastics,they contaminate the entire recycling process. Introducingjust one PVC bottle into the recycling process couldcontaminate 100,000 bottles, rendering the entireplastics stock unusable.PVCs in landfillIncineration is no solution, since burning forms dioxinsthat are released into the air or disposed of on land asash. As a result, most PVC products end up in landfill. Atthis point, many of the other chemicals and additivesused in the manufacture of PVC find their way into theenvironment causing further contamination.Governments and industry are taking action toeliminate PVC. The Danish and Swedish governments arerestricting PVC use, hundreds of communities worldwideare eliminating PVC in buildings, and leading companieshave committed to eliminating PVC from their products.Spelsberg is among them, building its market leadingsranges of enclosures from plastics such as polyethylene,polypropylene, polycarbonate and polystyrene. The costand performance of these alternative compounds all buteliminates the need for PVC, completely removing healthrisks while dramatically improving the overall recyclabilityat the end of life of products.With plastics so diverse in their applications and soprevalent in our daily lives, the regulations that controltheir use are becoming steadily tighter, focusing on airquality, end-of-life, toxic substances and fire safety. ForPVC, a tightening of the regulations surely cannot comefast enough. For its part, Spelsberg is committed to a PVCfreeenvironment, and is confident in its ability to meet anyuser application requirement for enclosures with any of anumber of other innovative, high performance, costeffective, and completely safe compounds.www.spelsberg.co.ukNovember 2010 • INDUSTRIAL TECHNOLOGY21
Page 1 and 2: www.industrialtechnology.co.ukIndus
Page 3 and 4: Flexible controller for up to 6 axi
Page 5 and 6: COMMENT & ANALYSISIndustrial Techno
Page 7 and 8: Plastic Protective Elements for Eve
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Page 17 and 18: Looking for aHEAVY DUTYLinearMotion
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Page 26 and 27: SENSORS & SYSTEMSEncodersMeasuring
Page 28 and 29: SENSORS & SYSTEMSVibration SensorsF
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Page 52: Windows ® . Life without Walls .

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