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Chris Lloyd of Spelsberg discusses some of the dangers relating to the use of halogen as a flame retardant in plastics and other products – something that all enclosure specifiers should be aware of.

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 not yet over.

Every year, in Europe alone, fire leaves more than 4,500 people dead and 40,000 severely injured.

Effective fire retardants to inhibit the combustion process are, therefore, vital.

The flame retardants themselves, however, have come under increasing scrutiny in recent years, with growing concerns over the impact of these chemicals on health and on 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 BPP and PBDE, but these, too, were found to be extremely harmful.

Bromine is one of the halogen range 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.

However, 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.

In addition, 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 US showed that nearly all American people tested had trace levels of flame retardants in their bodies.

In the European Union (EU), the introduction of the RoHS regulations and the WEEE directive banned the use of these most commonly used flame retardants.

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 700C, do not burn after UL 94 V-0 and are glow wire proof to VDE 0471.

However, these hazardous compounds are still very much a feature of our daily lives, most notably in polyvinyl chloride (PVC).

Second only to polyethylene in the prevalence of its use in plastics production and consumption, PVC is used in an large 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).

In product use, dioxins can bleed into the atmosphere from PVC products as they are broken down by ultraviolet (UV) light, building the potential for health problems.

There are also the dioxin emissions from the millions of annual fires that burn buildings, vehicles and consumer products – all major applications for PVC.

However, 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; as there are so many different formulations of PVC, there is no generic process to separate the PVC into its original formulation for recycling.

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.

Incineration is not a solution, as burning forms dioxins that are released into the air and 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 various companies have committed to eliminating PVC from their products.

Spelsberg builds its 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 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, the end of life, toxic substances and fire safety.

For PVC, a tightening of the regulations is necessary.

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