Statistics for Europe show an annual 325 fires for every million television sets compared with just six in the United States. The main reason for this is that TV housings on the old continent are still usually made from materials with little or no flame retardancy; in the United States, materials with the V-0 classification are used, in compliance with the U.S. fire safety standard UL94.
The risk of fire produced by televisions and IT equipment is now increasingly a focus of attention for the media and the public. The International Electrotechnical Commission (IEC) is also responding to the growing safety demands, with the IEC TC 108 - the standards committee with global responsibility for this area - currently laying down new requirements for flame retardance in TV sets. These can already be met by Bayblend® FR grades, flame-retardant polycarbonate (PC) blends from Bayer MaterialScience AG, and special grades of the Bayer MaterialScience polycarbonate Makrolon®.
"One of the aims of IEC TC 108 is to protect TV sets more effectively from external ignition sources like a burning candle that has toppled over,"
explains Michael Halfmann, fire safety expert at Bayer Industry Services.
Some 12 to 20 percent of all TV fires do not originate in the set but from an external fire source. The new standard therefore specifies areas of a TV set that can be reached by the flame of a candle that has fallen over. The TV must not catch fire in these areas even if it is exposed to the flame for three minutes.
"Our flame-retardant PC/ABS blends and PC grades do not just conform to IEC standards. They can also be used without any problems as a housing material that conforms to the WEEE and RoHS EU directives," says Guido Nachtigäller, Senior Sales Manager for the IT industry at Bayer MaterialScience. WEEE stands for "Waste Electrical and Electronic Equipment" and states that plastics containing brominated flame retardants must be removed from used electrical and electronic equipment and disposed of separately. The "Restriction of the use of certain hazardous substances in electrical and electronic equipment" (RoHS) directive prohibits the use of certain brominated chemicals in electrical and electronic equipment. The flame-retardant packages of Bayblend® FR (FR = flame-retardant) and the relevant grades of Makrolon® are free of bromine, chlorine, and antimony.
PC/ABS blends are long established as a housing material for printers, computers, monitors, and TV sets, for example, because they have excellent mechanical properties such as high dimensional stability and stiffness and outstanding toughness over a broad temperature range. In addition, they easily meet the existing illumination requirements for use in interiors.
Bayblend® FR 3005 HF is especially well suited for flame retardant TV housings and other large parts with thin walls as it is particularly free-flowing and can be processed extremely cost-effectively.
Flame-retardant PC grades such as Makrolon® 6557 can be used to produce transparent housings. For instance, Philips uses both types of material for its widescreen flat TVs with Ambilight™ technology. Light is generated on the sides of the set to complement the colors and light intensity on the screen and is emitted into the surrounding area by translucent bars made of flame-retardant Makrolon®. This light creates an atmosphere, provides more relaxed TV viewing, and enhances subjective image contrast. The rest of the housing for the Philips Ambilight™ TV is made from Bayblend® FR.