Fire protection and environmental protection of integrated wiring cables

With the popularization of information technology, there are a large number of communication cables that are in use or abandoned in buildings. Once a fire occurs in the building, the heat and poisonous gas released by these cables will become a major safety hazard. Throughout the large-scale fire accidents, many of them are due to the inability of the victims to escape, the burning of cables emits toxic acid gases, and the large amount of heat and smoke released by the combustion, causing the victims to have difficulty breathing, resulting in a tragedy!

Therefore, when users choose a comprehensive wiring system, in addition to performance considerations, fire protection and environmental protection are also very critical factors. This article will give a detailed introduction to the materials and how to select the cables of the integrated wiring system.

Integrated wiring cable

cable material

The protective sheath of a data cable is physically divided into two parts: an insulating layer and a jacket. Whether the cable has a fireproof function mainly depends on the material of the outermost sheath. At present, the communication cable sheath materials in the domestic market are mainly divided into three types:

1. Ordinary (PVC) type

At present, most of the cable jackets used in local area network wiring are made of PVC (polyvinyl chloride) material. PVC is added with chlorine element in polyethylene (PE) to improve the ignition point of the cable. Low, stable mechanical properties, the disadvantage is that the ignition point is low, the flame spreads fast, emits toxic smoke when burning, low visibility, and releases more heat when burning.

2. Low smoke halogen free type (LSZH/LS0H)

In order to comply with stricter environmental regulations, low-smoke halogen-free (LSZH) cables are produced without halogens. When burning, the cables have low toxicity and smoke concentration, which can reduce toxic gas emissions and damage to building equipment. Corrosion, thereby reducing casualties in the event of fire. Flame-retardant low-smoke halogen-free (LSFRZH/LSFROH) cable is to add aluminum oxyhydroxide or magnesium oxyhydroxide into the cable sheath. The burning speed is slower than that of PVC, and the ignition point is about 150 °C. The European Union has very strict requirements for the environmental protection of equipment materials used in buildings, so low-smoke halogen-free (LSZH) cables are widely used in Europe.

3. Fireresistant

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

Comprehensive Cable Selection Recommendations

The selection of fire protection or environmental protection level of integrated wiring cables should be comprehensively considered according to the actual situation of the site:

1. Raised floor or suspended ceiling

If there are PVC trunking/pipes in the raised floor or ceiling of the building and an air-conditioning ventilation system is installed, flame-retardant (CMP or OFNP) cables should be used in the raised floor or ceiling; Metal trunking/pipe or fire-resistant PVC trunking/pipe, 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 (airports, subways, stations, hospitals, exhibition centers, etc.), cables that conform to LSZH grade should be selected when designing integrated wiring projects, and metal wire troughs with fire protection functions should be used. Pipe or flame retardant PVC trunking/pipe.

2. Vertical shaft

If the vertical shaft of the building is a PVC wire duct (line pipe), the cable or optical cable of the vertical grade (CMR or OFNR) or above should be used in the vertical shaft; if the vertical shaft is a metal wire groove/pipe (or flame retardant PVC wire groove /pipe), cables of 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 the consensus of people. In addition to considering electrical performance in the construction of integrated wiring, long-term investment returns, such as fire protection or environmental protection, should also be considered. Low-smoke halogen-free cables are more and more popular because of their high performance and price, and they are more green and environmentally friendly.