1. Halogen (LS0H or LSZH) flame retardant material of evolution and the rise of cable
1. Cable in the harmful halogen-containing
Halogen (especially bromine) flame retardant polymer systems because of their outstanding results, before the mid-80's market share in the flame retardant polymer absolute dominance. Wire and cable industry in the polyvinyl chloride (PVC) is one example, sheathing and insulation compound still bears the main roles. Along with social progress and rapid development of science and technology, PVC inherent weaknesses (a lot of smoke when burned release, serious corrosive gases and toxic gases) all the more apparent. Since then, assessment and search for alternatives to PVC materials then become the focus of debate.
Back in 1986, first discovered in Europe in the combustion products containing polybrominated diphenyl ether, 4 benzo-dioxane bromide double and four other brominated dibenzo furans are carcinogenic. Until 2001, Britain has found five successive PBDEs, decaBDE wild falcon eggs in the bio-accumulation of 400 times higher than the domesticated falcon eggs. So once again refused to launch the production and use of brominated flame retardant action.
2. North America and Europe on cable in the understanding of fire
Over the past several decades has gradually into the halogen-free flame retardant system in Europe, and was accepted as part of a cable manufacturing technology. The United States is not the case, it is generally limited to products only sold back to Europe to do this provision. Europe and the U.S. based on different circumstances and backgrounds have a totally opposite view: that the United States, the concept of spread: bad disaster is the source of carbon monoxide (CO) gas generation and subsequent flashover ("flashover") into the process of CO CO2 heat release. Therefore, if the goods through a number of ways to improve the process of ignition and control of heat release, can reduce fire hazards.
North American UL certification bodies in North America, cable-based fire safety standards. To meet the UL standard halogen must be added to the cable insulation layer of polymer, its PVC cable containing chlorine, and FEP (Teflon PTFE Teflon Long, which is CMP) cable that contains fluoride. FEP has a strong fire resistance, before the dissolution of the burning smoke can withstand temperatures above 800 ℃, which is burning up more than 800 ℃. However, due to meet UL standards must be added to the cable when the halogen insulating layer of polymer, then burning of PVC cables will be San Fachu O'clock hydrogen fluoride and two oxide gas, they identified by Greenpeace as a "scientific Yizhi , the synthesis of toxic chemicals. " FEP cable when burning, it releases a colorless, odorless, but more toxic than hydrogen chloride hydrogen fluoride. A test showed that the smoke in the FEP there another dangerous gases.
Europe, said: halogen produced in the burning acid (HCL) emission, gas corrosive, toxic smoke and gas concentrations is to decide whether the security people are the main factors from the fire scene. Currently installed in most parts of the world's electricity and communication cables are halogen, such cables in the burning will emit toxic chemical mist. Scene of the fire, including halogen cable will produce acid gases, undermine staff nose, throat and other organs, the smoke also easily lost personnel, it is difficult to escape the fires. Therefore, most of Europe with low halogen or halogen element standard green type cable.
The seriousness of the scourge of the people depends on the success rate from the fire scene. Irritation and toxicity of smoke from the fire scene constraining factors. Therefore, the smoke produced by combustion, drugs, and corruption should be given priority attention. In other words, completely abandon the production and use of halogen material is a priority.
2. The characteristics of halogen-free cable
1. Does not contain halogen, does not produce harmful gases and corrosive gases
Halogen-free cable in the composition of materials, in addition to not use halogen elements, the phosphorus flame retardants are also excluded list. European cable manufacturers to meet stringent anti-virus norm, not the use of halogen and replace them with metal to polyethylene and poly vinyl cable insulation layer inside. When heated, this cable gives off toxic only a small visible steam.
2. Burning smoke less
Statistically, died in the fire one-third of the staff in the wire and cable inhalation of toxic gases when burned, release and choked to death, we propose a cable not only has good flame retardant properties, and should be available soon combustion gases produced in halogen-free acid (toxic gases) and low smoke, to ensure that personnel are not familiar with the scene, the opportunity to escape.
3. Does not contain lead, heavy metals, hormone free environment, not pollute the soil
Lead and lead compounds, will be the body's digestive and respiratory uptake in human blood and brain accumulation of harm to human health. When the cable through the broken skin, was buried, the lead compounds will escape from the chloride in the pollution of soil and water quality, harm to human.
4. Anti-aging well, can be a long time to ensure network quality
Four pairs of wire PVC cable insulation material for its core line of polyethylene (PE), so the use of polyvinyl chloride (PVC) when the jacket material, after a period of time, polyvinyl chloride (PVC) plastic oil itself on the move four of the line skin, will lead to its core line of insulating polyethylene (PE) medium change, resulting in network transmission characteristics of four pairs of lines worse. The factors such as the use of halogen (LSZH) material as the jacket, because the halogen elements (LSZH) material itself is a PE, but PE and PE does not produce prolonged exposure to mobile phenomenon. Hence it will not affect the four pairs of wire core wire cable dielectric polyethylene (PE), four pairs of wire line will not change on the characteristics, which can always ensure the quality of long cables.
Also, because the fire performance of such halogen-free cable as halogen cable, and will soon be burning the insulation layer. Therefore, more and more European cable manufacturers focus on production of halogen-type cable, and fire resistance cable, and has been developed to do with a halogen compound cable jacket, the fire rating has been quite CMR UL standards in the cable fire protection rating. This fire-resistant cables in case of fire to work, to continue transfer of power and data can be used for smoke alarms and emergency lighting. And the fire will not spread the fire, produced only a small amount of non-corrosive, non-toxic smoke.
3. Cable industry's progress
Wire and cable industries in particular. At present the world have a large number of wire and cable materials suppliers. Most manufacturers are working on the newly developed halogen-free materials and production. For example: Datwyler so. Already on the market for different kinds of uses (construction, communications, transport, railways, etc.) require different types of halogen-free cable products.
It should be noted, with the cable industry, except the power cable, the building electricity (220/240 V) cables, telephone cables and data cables have been significant progress. So far, the power cable (<1 kV) and 220/240 volt electricity cable compound is still more than half of PVC cable materials. General, building electricity cables and telephone cables are sheathed (PVC) + insulation (PVC); data cable: is the sheath (PVC) + Insulation (in density or high density PE). A trend that in the important occasions LSZH will gradually become the preferred material of these cables. For example, the United Kingdom since the tragic fire of London Royal subway station after the accident, authorities have explicitly adopted in public, must comply with the use of technology indicators LSZH cable material.
The emergence of modern computer networks, computer local area network drive (LAN) the rapid development, which led to the data transmission cable connected to each other the desire growing. Generally estimated that an average of 60 meters each computer's LAN cable. Therefore, the application of the two data cables can be imagined.
The face of opposition from the United States-based and take into account the future prospects for the development and further promote a non-halogen polyolefin cable material based cable industry, was established in 2001 in Europe FROCC (Fire Retardant Olefinic Cable Compounds) Association.
4. Environmental safety and standards regulations
General direction: environmental safety first. By enacting more stringent regulations and standards.
Fire safety standards around the world vary in North America are UL standard, which has specific fire safety standards for communication cable, and emphasized how to reduce the flame expansion, the fire spread and smoke production. In Europe and Asia, the fire safety standards for the communications cable does not exist, but in some European countries have low smoke zero halogen (LSZH) cable standard in Europe.
1. North America, what level of flame retardant standards?
North American UL standard by flame from high to low levels (for different regions), namely:
◆ Flame CMP (applicable to the air return duct or pressurized area)
◆ Class non-combustion route CMR (for vertical and horizontal areas trunk)
◆ Non-combustion-supporting business-class CM (used in horizontal area)
◆ general level of non-combustion CMG (used in horizontal area)
◆ general household level CMX (must be laying a single level)
2. Europe, low smoke zero halogen cable standards?
Europe, low smoke zero halogen cable contains the following three criteria:
◆ IEC60332-3 or IEC60332-1 (flame expansion and flame retardant).
◆ IEC61034 (smoke divergence)
◆ IEC 754 (corrosive and toxic)
3. IEC60332-1 and IEC60332-3 What is the difference?
IEC60332-1 (only for level) is the single thread of the vertical flame test, fire rating lower, easier to burn, and even fire off, it is likely to have tempered, carbon monoxide produced by combustion of a high . The IEC60332-3 (for vertical and horizontal) are a family of line with the vertical flame test, so fire safety rating than the much higher IEC60332-1, can be described as neither toxin, and can effectively fire. More important, life-saving devices would be easier to isolate the flame, while also greatly reduce the fire danger caused by a chain.
4. Different brands of cables meet the IEC60332-3 flame-retardant requirements are the same?
Not the same. Because in the IEC60332-3 standard also points A grade, B grade and C grade. A more consistent level of cable for testing, and test the flame burning for 40 minutes; meet C-level testing requirements of the flame burning time is only 20 minutes. Therefore, the cable line with IEC60332-3A meet IEC60332-3C than the cable requirements more stringent.
5. Halogen-free flame retardant cable materials, technical indicators
The overall direction of technology development:
1. To improve the high-tech products (such as interface compatibility technology, anti-aging technology, intumescent flame retardant technology, nano technology, special processing technology, etc.)
2. Strict three high-low two requirements: low smoke, low toxicity, low corrosion, high flame
3. To improve (quality / price) than
6. Halogen-free flame retardant cable materials in several new technologies
Halogen-free flame retardant cable materials development and materials science and technology closely related to the rapid progress. Today, material science and technology developed rapidly, new look, is directly related to halogen-free flame retardant cable materials, the future of the industry in the future. Several new technologies is worth noting the following:
1. Intumescent flame retardant technology: the chemical type and physical type two categories.
2. Polymer Nanotechnology: Polymer layered silicate (Polymer Layered Silicates)
3. Metallocene catalyst polymerization technology: such technology can be adopted by the special properties of polyethylene, polypropylene and other raw materials.
7. Conclusion
High-rise buildings within the pipeline clouds, all kinds of electrical cables crisscrossing the strength, as long as one has fire, if not promptly extinguished quickly spread to the entire building. Meanwhile, people perished in the fire, most are not being burned to death, but because of inhalation of combustion products emitted by the choking smoke and toxic death.
In the final analysis, integrated wiring is a subsystem of a building, capacity building as a whole does not only depend on the flame retardant cable of the flame retardant cabling capacity, customer choice must be comprehensive consideration when monitoring, access control and so on cable and flame retardant pipeline capacity, according to the actual needs and situation at the scene and then decided to use low smoke zero halogen cables or other types of cables. In the building, smoke detection, fire linkage, sprinkler system, fire shutter, fire training, fitting systems, and fire prevention awareness, these factors are important to note, the only way to achieve the purpose of fire prevention.