In Europe and The United States, low-smoke, flame retardant, non-toxic materials have been widely used, because in the event of fire, nearly 80% of the deaths are caused by the strong and even toxic smoke generated during the fire caused by suffocation coma, so that people lose the opportunity to escape. In order to evaluate the flame retardant performance of cables, IEC 60332.1, IEC 60332-2 and IEC60332-3 have been formulated respectively by the International Electrotechnical Commission. IEC 60332-3 is used to assess the flame retardation of bunched cables during vertical combustion. The corresponding national standard is GB/T 18380.31-36. Since most cables used in engineering are bunched rather than single laid, the flame retardation performance is determined by the flame retardation of bunched cables during vertical combustion. The international standards for flame retardant cables are divided into two systems: the European system (including IEC, BS, etc.); The second is the American system (including UL, CSA and other standards). The biggest difference between these two systems is the vertical combustion test of bunched cables. China's national standards for flame retardant wire and cable have been equivalent to IEC standards, such as GB/T 18380.31-36 "Fire Tests of Cables and Optical Cables under flame Conditions" is equivalent to IEC 60332.3-2000
1 Cable type
1.1 Flame retardant cable
Flame retardant cable (Z) is difficult to fire, is the ability to stop or slow the spread of flame wire and cable. The cable usually refers to a wire or cable that passes the test of GB/T 18380.3(equivalent to IEC 60332.3). Flame retardant cable with provisions of the flame retardant performance, and in accordance with GB/T 18380.31-36 A, B, C, D four types, according to the specific standards for smoke density and toxicity of flue gas can be divided into I, Ⅱ, Ⅲ, Ⅳ four levels. Flame-retardant cable is characterized by the retardation of flame spread along the cable so that the fire will not expand. Because of its low cost, it is widely used in flame retardant cables. Whether laying single cable or laying in bundles, the spread of flame can be controlled within a certain range when the cable is burned, so as to avoid the major disaster caused by the cable fire and burning, and improve the fire prevention level of the cable line.
1.2 Halogen-free, low smoke and flame retardant cable
Halogen-free and low-smoke flame retardant cable (WDZ) is characterized by not only excellent flame retardant performance, but also the halogen-free material of the low-smoke halogen-free cable has low corrosion and toxicity during combustion, and produces a very small amount of smoke, which reduces the damage to human body, instruments and equipment, and is conducive to timely rescue in case of fire. Halogen-free and low smoke flame retardant cable has excellent flame retardant property, corrosion resistance and low smoke concentration.
1.3 Low halogen and low smoke flame retardant cable
The hydrogen chloride release and smoke concentration of low - halogen and low - smoke flame - retardant cable (LSF) were between flame - retardant cable and non - halogen and low - smoke flame - retardant cable. Materials for low-halogen cables may also contain halogens, but at lower levels. The cable not only has flame retardant properties, but also releases less smoke and hydrogen chloride during combustion. Low-halogen and low-smoke flame retardant cables are generally made of POLYvinyl chloride (PVC) as the base material, and then processed with efficient flame retardant agent, HCL absorbent and smoke suppressant, which significantly improves the combustion performance of common flame retardant polyvinyl chloride materials.
1.4 Fire retardant cable
Fire-resistant cable can maintain normal operation for a certain time under the condition of flame combustion, which can maintain the integrity of the line. Fire-resistant cables are divided into fire-retardant cables and halogen-free fire-retardant cables. The amount of acid gas smoke produced by fire retardant cables is less, and the flame retardant performance is greatly improved. Especially during the combustion, the cables can still keep the line intact under the conditions of water spraying and mechanical shock.
Metal-clad cables were developed by Edwin Field and Gus Johnson in the United States in the early 1900s as BX cables. With continuous improvement, the advantages of metal armored cables are gradually reflected, such as high strength, corrosion resistance, high flame retardant performance, cost saving and installation cost, light weight (aluminum alloy armored tape and aluminum alloy conductor), reduced loss (such as aluminum alloy armored material is non-magnetic, reduce eddy current loss), etc. Moreover, armored cables have been included in Canadian CSA22.2 NO.51-95 American UL44, with a long-term and stable operation history in North America, and are widely used in hotels, supermarkets, colleges, gymnasiums, hospitals, prisons, airports, military bases, data processing centers, industrial fields and other places.
2. Low smoke, halogen-free and flame retardant performance of new type alloy cable
2.1 Low smoke characteristics
According to the requirement for low smoke cable (according to GB/T1765 1.2-1998 "cable or optical cable under certain conditions the burning smoke density measurement"), the light transmittance of qualified standard is 60% or higher, armoured cable and aluminum alloy in national fireproof construction material quality supervision inspection center test results for 99, the aluminum alloy armoured cable after burning light transmittance of 99%, basic cable products can be called a smoke-free. (See the inspection report of alloy cable for this data.)
2.2 Halogen-free characteristics
Because aluminum alloy armored cables are cross-linked polyethylene insulated XLPE and corrugated interlocking armor, they do not contain halogens, and their smoke toxicity meets the national standard GB/T 20285-2006(classification of smoke toxicity hazard of materials), which meets the requirements of national smoke toxicity safety grade.
2.3 Flame retardancy characteristics
According to GB/T 18380.33-2008, Cables under flame conditions - Part 33: Vertical installation into cable vertical flame spread of test requirements of the "class A, the length of 3.5 m of wire or cable (the total root number because of the flame retardant type and cable per meter of varies of non-metallic materials) into A bunch of installed on the sample of ladder, and vertical in 1 000 mm x 000 mm x 4 000 while NLM test box, with strength of 20.6 kW plane of propane burner at 750 oC flame contact with sample, the sample in the compulsory blowing (air emissions from 5 m/min, wind speed 0.9 m/s) vertical wire and cable for fire. The fire supply time of class A and B flame retardant wire and cable is 40 min. The fire supply time of class C and D is 20 min. After the end of the test, the carbonization height of the wire and cable shall not exceed 2.5 ITI for passing. After class A flame retardant test, the charring height of the cable after combustion is only 0.15m, far higher than the requirements of national standards. In North America aluminium alloy armored cables must pass the FT4 test, which is more rigorous and requires a combustion source of 20. Angle feed cable for fire, carbonization height requirement is also less than national standard 2.5 NL, 1.5 ITI.
2.4 Non-toxic and environmental protection characteristics
RoHS is a mandatory standard set out by European Union legislation that is fully called the Directive of Restriction of Certain Harmful Substances in Electrical And Electronic Equipment. The standard, which came into effect on July 13, 2006, is mainly used to regulate materials and process standards for electronic and electrical products to make them more conducive to human health and environmental protection. The aim of the standard is to eliminate six substances in electrical and electronic products: lead, mercury, cadmium, hexadecent chromium, polybrominated biphenyls and polybrominated biphenyls (PBDes), with emphasis on a limit of 0.1 per cent of lead.
The use of lead has been abolished in developed countries, but in some developing countries, such as in my own country and In India, its use has been greatly reduced, but it is still a cause for concern. In the mid-1990s, the proportion of lead needed for cable production in China still accounted for 7% of the world's total demand for lead. China's current production of PVC cable materials, the most commonly used is a kind of salt based lead salt stabilizer, including lead white, lead sulfate tribasic, lead phthalate, lead stearate and lead stearate. Metallic lead, by weight, accounts for approximately 113% ~ 212% in PVC formulation. In addition, PVC dyes contain cadmium and chromium, and antimony trioxide (Sb O) is widely used as a flame retardant coagent. The amount used in every 100 copies of PVC resin can reach 2 ~ 3 copies. Lead series stabilizer has excellent performance and low price, the purpose of application is to ensure the heat stability of PVC. In order to improve the flame retardancy of PE cable materials, decabromodiphenyl ether (C), commonly known as decabromodiphenyl flame retardant, is widely used in the cable industry. Br.) . Only a small amount of this flame retardant can make PE cable material have a very high flame retardant property, while PVC cable material has a very good flame retardant property because it is rich in chlorine atoms. However, in order to improve its flame retardant level, halogen flame retardant is still widely used. Plastics containing decabrominated flame retardants produce highly toxic dioxin-like dioxins and benzofurans bromide when they are partially burned. In China, The STABILOY~ World Alloy @za-AC90 (a 40) cable produced by Alcan (Tianjin) stabilised oy ~ World alloy @ Za-AC90 (a 40) offers a high level of heavy metal control in the raw material and production process, with no lead, bromine, or heavy metal in the insulation and jacket materials, and is consistent with the European Union's RoSH limitation on the six toxic materials.
3 the knot language
To sum up, the aluminum alloy armoured cable through the national fireproof construction material quality supervision inspection center of detection, project indicators are measured by and by more than the national standard requirement, has many instances of installation at home and abroad, such as the Venetian hotel in North America, the Georgia dome Olympic center stadium, the Shanghai world expo, such as project, its features, such as economy, environmental protection, flame retardant received widespread high praise, is worth vigorously promoted in domestic.