Regarding the selection and standard of the data cable sheath of the integrated wiring network, the standards organizations and manufacturers in North America and Europe have been arguing about the use of UTP or FTP shielding products for a long time, and they will not give in to each other. At present, North America, South America, Asia Pacific and China all adopt the North American cable fire protection standards UL and NEC (National Electrical Code), and parts of Europe adopt low-halogen or low-smoke halogen-free green cable standards.

Controversy over halogen in the outer skin

At present, the integrated wiring power and communication cables laid in most parts of the world contain halogens, which emit toxic mist-like chemicals when burned. In a fire, halogen-containing cables can produce acid gas, which damages workers’ noses, mouths and throats. The smoke also makes victims easily disoriented and difficult to escape from the fire.

Recognizing this potential hazard, some European countries have adopted halogen-free cables as the standard for power and communication cables. However, the National Electrical Code of the United States clearly stipulates that the integrated wiring communication network must use a Category 5 or Category 6 UTP (unshielded twisted pair) network cable with a halogen-containing coating. This is because although the halogen-containing cable has important defects, the halogen itself has strong flame resistance and high ignition point. If the cable does not catch fire at all or is difficult to catch fire, it will not cause combustion and emit toxic smoke. .

In fact, some fires are caused by overheating of the integrated wiring cable itself for a long time. Halogen-free cables are more likely to cause fires because of their low ignition point, and the halogen insulation layer can better prevent the cables from igniting themselves. However, if the cable is already in the fire, the smoke it produces will cause life poisoning. These contradictions have always been the focus of debate in the industry in the application of halogens.

Now, advocates of cable halogens, including companies such as the United States Federal Corporation and Goodrich, occupy a leading position in technology. Opponents of halogen hope to be more able to persuade the NFPA (National Fire Protection Association) to modify the current standards to stop the use of halogen or allow the use of halogen-free cables in the ventilation of buildings.

This is not the first time the advocates of halogen-free cables have tried to modify the standard, but it has not been successful so far. ***The main reason is that the spontaneous channeling combustion of the cables in the trunk trunking makes it difficult for people to carry out regional fire control, which causes fires in the entire building, and the low ignition point is very easy to produce fire sources. The other main reason is that there is no evidence that halogen-free cables can indeed save lives (because there are a lot of other decorations in the house that also contain halogen).

According to the current US Building Act, the only halogen-free cable that can be legally installed is to place the integrated wiring cable in a metal conduit, which doubles the cost of the entire wiring system. Therefore, most European countries including France, Italy and the United Kingdom have switched to halogenated cables. In Europe's communication cables, halogen-free cables currently account for about 25%, while in North America and most parts of the world, halogen-free cables account for more than 98% of the market. Cabling manufacturer Avaya has launched a full range of data cable solutions for users in different standards and regions to meet the needs of different users.

Advantages of halogen-free

The characteristics of halogen-free are: low ignition point, flammable but low toxicity. At present, relevant international standards concerning integrated wiring cables mainly focus on three issues: fire resistance (the speed at which the cable burns), smoke density (how much visible smoke is produced), and toxicity (how much damage is caused to the human body). The American fire protection standard only covers the first two issues, but it is more extensive and strict in use. To meet the American standard, halogen must be added to the polymer of the cable insulation layer. The PVC cable contains chlorine. FEP (Teflon Teflon polytetrafluoroethylene) cables contain fluorine.

FEP has strong fire resistance. It can withstand temperatures up to 800°C or more before burning and disintegrating. It is several times higher than the usual halogen-free cable, which can withstand the highest temperature of 150°C. At the same time, FEP is also effective. The insulator. Therefore, FEP is very suitable for making cables for transmitting high-speed data, and it is a key factor in the widespread use of Category 5 UTP in ventilation places. In high-rise shafts and other ventilated places, FEP cables have largely replaced PVC cables. Some European countries have different standards. In order to comply with strict anti-toxicity regulations, manufacturers of integrated wiring cables do not use halogens. Instead, metals are added to the insulation of polyethylene and polyene cables. When heated, this cable emits only visible vapors with little toxicity. However, the fireproof performance of this halogen-free cable is not as good as that of halogen-containing cables, and the insulation layer will burn quickly. Therefore, halogen-free cables cannot meet the strict American fire protection standards. To meet the fire protection requirements of ventilation and exhaust areas, excessive metal hydroxides have to be added, which affects cable performance and technical requirements.

Cable Toxicity Controversy

When the PVC integrated wiring cable burns, it emits hydrogen fluoride and dioxide gas. They are identified by Greenpeace as "scientifically known, toxic synthetic chemicals." When FEP cable burns, it releases colorless, odorless, but more toxic hydrogen fluoride than hydrogen chloride. Tests have shown that there is another dangerous gas in FEP smoke. This kind of super porn has never been correctly recognized by humans, and now the research on it has stopped, but some people think that this super porn is only an experimental product, not in reality. exist.