Thứ Tư, 16 tháng 5, 2012

Some flame retardants make fires more dangerous

A report delivered at the National Meeting & Exposition of the American Chemical Society (ACS) claims that some of the flame retardants added to items such as carpets and furniture upholstery are actually increasing the danger of invisible toxic gases.
These gases are the number one cause of death in fires, according to Anna Stec, who led the research, which focused on the most widely used category of flame retardants, which contain the chemical element bromine. Scientists term these “halogen-based” flame retardants because bromine is in a group of elements called halogens.

“Halogen-based flame retardants are effective in reducing the ignitability of materials,” Stec said. “We found, however, that flame retardants have the undesirable effect of increasing the amounts of carbon monoxide and hydrogen cyanide released during combustion.”
Stec, of the University of Central Lancashire, Centre for Fire and Hazards Science in the United Kingdom, spoke at an ACS symposium on “Fire and Polymers,” which included 60 presentations.
These brominated flame retardants are used in a wide range of products including those made from polyurethane, such as mattresses, furniture, and car and airline seats.
Almost 10 000 deaths from fires occur in industrialized countries worldwide each year, including about 3500 in the US, according to a ACS news release, which added that it is the inhalation of toxic gases released by burning materials, not burns, that causes the most deaths and most of the serious injuries.
Stec’s team set out to determine the effects of flame retardants on the production of those gases. The scientists tested brominated flame retardants with antimony synergists, mineral-based flame retardants and intumescent agents, which swell when heated, forming a barrier that flames cannot penetrate.
Unlike the halogen-based retardants, mineral-based fire retardants have little effect on fire toxicity. Most intumescent fire retardants reduce the amount of potentially toxic gases released in a fire, the study found.
Nguồn: http://en.puworld.com/news_article-394643171.html