【 Weak current College 】 multiple cable jacketing of characteristic description

Over the years, the industry on network data cable jacketing of wrangling, such as the skin can meet the flame or low smoke? do you need to have high fire-resistance to fire, but fire but give off toxic gases in halogen? network cabling professionals, the vast number of network users and even in different parts of the standard organizations, there are differences. With integrated voice, data and image as a whole, multimedia broadband, Fusion network era, more in depth network wiring of households, the correct understanding of network data cable jacketing of composition and properties, the builders of the future network and the user's work and life are very important.

For network data cable jacketing of choice and standards, North American and European standards organisations and manufacturers like they use UTP or FTP shielded products, controversy has existed for a long time, Moscow. Currently, North America, South America, Asia Pacific and China are based on the North American cable fire standards UL and NEC (NationalElectricalCode), the European part of the low halogen or low smoke zero halogen green-friendly cable standards.

Jacketing halogen controversy

The current global power in most parts of the installation and communication cables contain halogen such cable in combustion, will give off toxic spray chemicals. Before the fire, halogen cables will produce acid gases, prejudicial to the workers on the nose, mouth and throat, smoke also makes it easy to get lost, the victims is difficult to escape from the fire scene.

Recognizing the potential harm, some European countries have halogen-free cable for power and communication cables. However, the United States national electrical code is defined: communication network must use with halogen clad in hyper-v or VI class of UTP (unshielded twisted pair) cable to the network. This is because, although containing halogen cables has important deficiency, halogen itself has a strong resistance to fire and high ignition point, if the cable does not catch fire or difficult to ignite, it does not cause combustion, thus give off toxic fumes.

In fact, some fire because the cable itself power longer lead to overheating. Halogen-free cable for so low, therefore more vulnerable to fire, and halogen insulation can better prevent cable spontaneous combustion. However, if the cable is already in the fire, the smoke can cause life-poisoning. These contradictions in the application of the halogen has been the industry debate.

Now cable halogen advocates, including the United States Federal companies and Goodrich, the company occupies a leading position. Halogen's opponents hope to convince the NFPA (United States Fire Protection Association) to modify the current standard, stop using halogen or allowed in the building's ventilation Department uses halogen-free cables.

This is not a halogen-free cable advocate first attempt to modify the standard, but so far have not succeeded. The main reason is that trunk cable trunking in spontaneous combustion of channeling layer makes it difficult to conduct regional fire control, thus giving rise to fire the entire building, and so very easy to produce a low fire. Another main reason is no evidence of halogen-free cable can save lives (because there are a large number of homes and other decorative objects also contain halogen).

In accordance with the present United States building Act, only to legitimate installation of halogen-free cables is the cable over the metal conduit, which makes the whole distribution system of cost doubled. Therefore, most European countries including France, Italy and the United Kingdom have turned to the use of halogen-free cables. European communication cables, halogen-free cable currently account for about 25%, while in North America and most parts of the world, is halogen-free cable with more than 98% of the market. Cabling manufacturer Avaya company for different standards and different regional users, has launched a full range of data cables solutions to meet different user requirements.

Halogen's advantages

Halogen's characteristics are: low, igniting combustible but toxicity. Currently involving cable-related international standards, primarily focused on three issues: fire resistance (cable burning speed), smoke density (how many visible smoke) and toxicity (on the human body produces much of the damage). United States fire standards only cover the first two issues, it is in use on more extensive and rigorous standards, to meet the United States must be added to the cable insulation halogenated polymers, PVC cable containing chlorine, FEP (Teflon PTFE corrugated Teflon) cable contains fluoride.

FEP has a strong fire, burning smoke before the breakup can stand up to 800 ° c the temperature of the above, it is usually non-halogen cables of up to 150 ° c of temperature endured to high number of times that of the FEP is also an effective insulator. Therefore, the FEP is ideal for making the cable high speed data transmission, is currently widely used in the ventilation Department-5 UTP. In the Tower shaft and other ventilating place, FEP cable has a large number of replaced PVC cables. European standards are different in some countries, in order to comply with the stringent specifications of the anti-virus, cable manufacturers not using halogen, replacing it with the metal into polyethylene and vinyl cable insulation within. When heated, the cable only gives off toxic small visible vapor. However, this kind of halogen-free cable with fireproof performance than halogen cables and their insulating layer soon will burn. Therefore, halogen-free cable does not comply with the strict fire protection standards of the United States, to achieve the ventilation and exhaust at the level of fire protection requirements, you have to join the excess metal hydroxide, thus affecting the cable performance and technical requirements.

Cable toxicity controversy

When PVC cable combustion will emit hydrogen fluoride and dioxide gases, they are green peace organization identified as the "Science of known, synthesis with toxic chemicals." When the FEP cable Burns, it releases a colorless, tasteless, but stronger than the toxicity of hydrogen fluoride hydrogen chloride. Some testing has shown that the smoke in the FEP is also another kind of dangerous gas. This Super toxin has never been human understanding, now it also has stopped, but some people think that this is only for Super toxin production in experimentalProducts that do not exist in reality.

Europe's Anderson laboratory use is known as the Pittsburgh testing methods (this method is called by the Pittsburgh University) to measure the cable jacketing of toxicity. In tests, burning a certain amount of insulation smoke through the catheter will be sent to the NIH is located 4 only, observation of space until 2 only albino rats died. When burning the insulating layer weight for a unit of toxicity LC50, meaning that so many of the insulating layer burning will kill the majority of the animal. Through this test, it was found that the toxicity of FEP cable is 1.5 times PVC cables, halogen-free cable with 5 times. FEP supporters were of the view that this test is academic, since the test environment is not a real fire site, and in the building reached release toxic gases when the required temperature, whatever people because the temperature is too high (800 ° c) and dies.