低烟无卤电力电缆--电线电缆型号的选择方法以及注意事项

Selection method and precautions of wire and cable model

Author：hlyb Add Time：2016-04-21 16:49:29

With the popularization of information technology, there are a large number of cables in use or abandoned in buildings. In case of fire in buildings, the heat and toxic gas released by these cables will become a major potential safety hazard. According to the data of relevant domestic departments, the direct economic loss caused by fire in China every year is at least 0.65% of GDP and up to 5000 deaths. Looking at several large-scale fire accidents in * * * in recent years, many of them are due to the victims' inability to escape, the cable combustion emits toxic acid gas, and the large amount of heat and smoke released by the combustion, resulting in the victims' dyspnea and tragedy!

Therefore, when users choose generic cabling system, in addition to performance considerations, fire prevention and environmental protection are also very key factors. This paper will make a detailed introduction to the materials and selection of cables in generic cabling system.

Cable material

The protective sleeve of data cable is physically divided into two parts: insulating layer and jacket. Whether the cable has fire protection function mainly depends on the material of * * * outer sheath. At present, there are three kinds of communication cable sheath materials in the domestic market:

1. Ordinary (PVC) type

At present, PVC (polyvinyl chloride) is used as the cable jacket for most local area network wiring in China. PVC adds chlorine into polyethylene (PE) to improve the ignition point of the cable. PVC cable has the advantages of low price and stable mechanical properties, but has the disadvantages of low ignition point, fast flame spread, toxic smoke during combustion and low visibility, More heat is released during combustion.

2. Low smoke halogen-free type (LSZH / ls0h)

In order to comply with more stringent environmental protection specifications, halogen is not used in the production of low smoke halogen-free (LSZH) cables. When burning, the toxicity and smoke concentration of such cables are very low, which can reduce the emission of toxic gases and the corrosion of equipment in the building, so as to reduce casualties in case of fire. Flame retardant low smoke halogen-free (lsfrzh / lsfroh) cables add aluminum hydroxide or magnesium hydroxide into the cable sheath. Once the cable is burned, the flame retardant effect comes from the water generated during combustion. The combustion speed is slower than that of PVC, and the ignition point is about 150 ℃. The European Union has very strict requirements on the environmental protection of equipment and materials used in buildings, so low smoke halogen-free (LSZH) cables are widely used in Europe.

3. Fire resistant type

The fire resistant type generally uses PTFE (polytetrafluoroethylene) or FEP (ethylene fluoride propylene) as the jacket. PTFE or FEP is also an effective insulator, and the combustion smoke concentration is very low. Because fluorine has stronger fire resistance, its ignition point is higher than frpvc and LSZH, and the ignition point is as high as 800 ℃. When FEP cable burns, it releases hydrogen fluoride, which is colorless and tasteless, but more toxic than hydrogen chloride. The toxicity of FEP cable is 1.5 times that of PVC cable and 5 times that of halogen-free cable.

Comprehensive cable selection suggestions

Because the construction habits of domestic buildings are different from those in Europe and America, the selection of generic cabling cables can not simply copy foreign standards. Code for design of generic cabling engineering (gb50311-2007) issued by China in 2007 introduced the grade of cable fire prevention and environmental protection for the first time. This standard recommends that domestic users choose different grades of fire prevention or environmental protection cables according to different occasions. The selection of fire protection or environmental protection grade of generic cabling cables shall be comprehensively considered according to the actual situation on site:

1. Raised floor or ceiling

If PVC trunking / pipe and air conditioning and ventilation system are installed in the overhead floor or ceiling of the building, flame retardant (CMP or ofnp) cables should be used in the overhead floor or ceiling; If metal trunking / pipe or fireproof PVC trunking / pipe is used in the overhead floor or ceiling of the building, cables of any fire rating (cm / / CMR / CMP or ofn / ofNR / ofnp) can be used. For buildings with environmental protection needs, such as crowded places (airport, subway, station, hospital, convention and Exhibition Center, etc.), cables conforming to LSZH grade should be selected in the design of generic cabling project, and metal trunking / pipe with fire protection function or flame-retardant PVC trunking / pipe should be used.

2. Vertical shaft

If PVC trunking (conduit) is used in the vertical shaft of the building, cables or optical cables above the vertical grade (CMR or ofNR) shall be used in the vertical shaft; If metal trunking / pipe (or flame retardant PVC trunking / pipe) is used in the vertical shaft, cables with any fire rating (cm / CMR / CMP or ofn / ofNR / ofnp) can be used in the vertical shaft.

To sum up, green environmental protection has become a consensus. In addition to considering electrical performance, long-term return on investment, such as fire prevention or environmental protection, should also be considered in the construction of generic cabling. Low smoke halogen-free cable is more and more favored by people because of its high performance, high price and more green and environmental protection. Tyco electronic Anpu cabling has provided high-performance, fire-proof and environment-friendly generic cabling products for many large projects in China. It is believed that the application of low smoke halogen-free cables will be seen more in future buildings, such as commercial office buildings, data center computer rooms, government office buildings, hospitals, subway stations, railway stations, airports, hospitals and other places.

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