Frequently Asked Questions on Flame Retardants

Flame Retardants Frequently Asked Questions The European Flame Retardants Association EFRA - The European Flame Retardants Association Chemistry making a world of difference Compiled and edited by Adrian Beard, Clariant, fire test photos by Ralf Baumgarten taken at Siemens Brandversuchshaus in Frankfurt- Hoechst and BayerIndustryServices Fire Test Laboratory in Leverkusen. We thank the teams of Knut Bauer and Michael Halfmann for their help and technical assistance. Cover photos: Candles are a common cause of ignition for domestic fires. The stereo shown on the front cover is engulfed in flames after 7 minutes when ignited with a small flame - see the photo on the back cover. Contents Flame Retardants Frequently Asked Questions Flame Retardants - General Aspects 2 General Fire Safety 4 Fire Safety Standards and Regulations 8 Flame Retardants and other Safety Technologies 12 Flame Retardant types and applications 14 Brominated Flame Retardants (BFRs) 16 Flame Retardants based on Phosphorus Compounds (PFRs) 18 Mineral flame retardants 20 Nitrogen-containing Flame Retardants 22 Other Flame Retardants - Borates, Stannates, ... 24 Flame Retardants - Health and the Environment 26 Recycling and Waste Management of Flame Retardants 32 Common Abbreviations for Flame Retardants 35 Literature and Further Reading 36 EFRA Members 37 1 Flame Retardants Frequently asked Questions Flame Retardants - General Aspects What are flame retardants? Flame retardants are chemicals which are added to combustible materials to render them more resistant to ignition. They are designed to minimise the risk of a fire starting in case of contact with a small heat source such as a cigarette, candle or an electrical fault. If the flame retarded material or an adjacent material has ignited, the flame retardant will slow down combustion and often prevent the fire from spreading to other items. Since the term “flame retardant” describes a function and not a chemical class, there is a wide range of different chemicals which are used for this purpose. Often they are applied in combinations. This variety of products is necessary, because the materials and products which are to be rendered fire safe are very different in nature and composition. For example, plastics have a wide range of mechanical and chemical properties and differ in combustion behaviour. Therefore, they need to be matched to the appropriate flame retardants in order to retain key material functionalities. Flame retardants are thus necessary to ensure the fire safety of a wide range of materials including plastics, foam and fibre insulation materials, foams in furniture, mattresses, wood products, natural and man-made textiles. These materials are e.g. used in parts of electrical equipment, cars, airplanes and building components. 2 tronic equipment where the accel- litres of petrol? Flame retardants erating processor power, electronic can be applied to many different sophistication but at the same time flammable materials to prevent a miniaturisation, result in a concen- fire or to delay its start and propa- tration of energy and an increase in gation by interrupting or hindering risks of local overheating or other the combustion process. They thus electrical fire risks. Flame retardants protect lives, property and the en- can prevent an increase in fire risk vironment. Flame retardants con- from the growing number of con- tribute to meeting high fire safety sumer and electronic goods in hom- requirements for combustible ma- es and offices. Flame retardants terials and finished products pre- protect modern materials such as scribed in regulations and tests. Al- technical plastics, building insula- though fire safety can be achieved tion, circuit boards and cables from by using non-combustible materials igniting and from spreading a fire. in some cases or by design and en- gineering approaches, the use of Once a fire starts in a room of a flame retarded materials often house, it can develop rapidly, if it meets the functionality and aesthet- spreads to items other than that ic requirements of the consumer as first ignited. Once a number of well as offering the most econom- items are burning, the temperature ical approach. in the room will rise, and may reach "flash over" point, when hot burning gases cause effectively the whole Examples: room to catch light, often violently. Once this occurs, escape from the Metal casings for electrical equip- room is impossible, and spread of ment afford fire safety, but pose the fire to other rooms is very likely. electrical risks, as well as being Flame retardants act both by pre- heavier, more expensive and less venting the initial start of a fire by design flexible than modern plas- impeding ignition and by delaying tics. the spread of the fire, thus increasing escape time, and perhaps pre- An increasing use of plastics in venting "flash over". cars, trains and aeroplanes offers lower weight and so improved fuel economy, but necessitates What are the benefits of flame retar- flame retardants to ensure fire dants? safety. Most people do not realise that their Mineral fibres for building insul- television set, sofa, mattress and ation are not flammable, but may Why do we need flame retardants? computer are all made essentially not offer the same energy perfor- from plastics (originally made from mance, structural characteristics Both our homes and offices contain crude oil), and without the inclusion or flexibility of application as poly- an increasing potential "fire load" of flame retardants many of these mer foams. of flammable materials because of products can be set alight by just a the development of electrical and short circuit or cigarette and be- Even where non-flammable mate- electronic equipment, and of rising come a burning mass in just a few rials such as steel are used, flame levels of comfort (furniture, carpets, minutes. Did you know for example, retardant intumescent coatings can toys, magazines and papers ...). that a regular TV set contains in its provide valuable heat protection for The potential causes of fires also combustible plastics an energy con- these to limit or delay mechanical tend to increase, especially in elec- tent which is equivalent to several deterioration in the case of fire. 3 Flame Retardants Frequently asked Questions General Fire Safety How large is the number of victims from fires? Statistics show that generally between 10 and 20 fire deaths per 1 000 000 inhabitants are reported in the major industrial countries of the world. The number of severely injured people is estimated at ten times this figure, i.e. 100 to 200 per 1 000 000 inhabitants per year. Every day in Europe there are about 12 fire victims and 120 people severely injured. About 80 % of all fire deaths occur in residential buildings. The people most at risk are the very young and the elderly because they are least able to escape in the event of a fire. www.flameretardants.eu/pdf/0602/fire_stat0602.pdf and World Fire Statistics www.genevaassociation.org 4 What is the most common cause of death in fires? The most common cause of death in fires is to be overcome by gas or smoke: In the UK, around 50 % of people die this way, while 25 % of deaths are due to burns and 20 % are attributed to both burns and being overcome by gas or smoke. 5 % of fire deaths cannot be speci- fied. Accidental fires in the home have far higher casualty levels than any other location. Why are fire gases toxic? Fires gases are toxic, because in all Besides these volatile gases, some fires toxic products are formed from more complex products are formed the incomplete combustion of or- like polycyclic aromatic hydrocar- ganic materials like plastics, wood, bons (PAHs) or halogenated dioxins textiles and paper. The component and furans (PXDD/F). These pro- which usually dominates the toxicity ducts are formed in much lower of fire effluents is carbon monoxide quantities and are not relevant for (CO), which is responsible for over acute toxic effects but they can have 80 % of all people killed by fire gas- long term health effects. However, es. One striking example is the Düs- because they are higher molecular seldorf Airport fire in 1996: here, all weight substances, they are mostly 17 fire deaths were due to CO poi- adsorbed to soot which reduces soning. By delaying the combustion their toxic potential. The polycyclic of treated materials and the spread aromatic hydrocarbons are typical of the fire, flame retardants signifi- products from incomplete combus- What is the economic damage cantly reduce the emissions of toxic tion of organic materials and they caused by fire? gases. dominate the long-term toxicity of Besides CO, many other toxic com- soot. The conclusion from many The total economic damage is esti- ponents can be formed in a fire: studies carried out on this subject mated at about 25 billion € per year Hydrogen cyanide (HCN) may be is that although the substances in Europe. In Germany alone, com- formed from plastics like polyur- emitted from fires are very variable, pensation costs covered by insur- ethane and polyamide as well as depending on fire conditions, the ance companies amount to 1.5 bil- from natural products which con- toxicity is above all a function of the lion € per year and there are about tain nitrogen like wool and leather. quantity of material burned. 200 major fire incidents with dam- Irritant fire gas components are ages in excess of 0.5 million €. hydrogen chloride (HCl) evolving from plastics like PVC and acrolein www.flameretardants.eu/pdf/ www.gdv.de, www.nfpa.org (USA) released from natural products like babrauskas_summary.pdf wood. However, compared to the toxic potential of CO, which is pre- www.flameretardants.eu/pdf/ sent in large quantities in all fires, prison_mattress.pdf the other fire gas components usu- www.sp.se/fire/Eng/Research/ ally only play a minor role.

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