It is easy for ordinary people to confuse the concept of flame-retardant cables and fire-resistant cables. Although flame-retardant cables have many advantages that are more suitable for chemical companies, such as low halogen, low-smoke and flame-retardant, in general, fire-resistant cables can replace flame-retardant cables. , And flame-retardant cables cannot replace fire-resistant cables.
The two principles are different. The flame-retardant principle of halogen-containing cables is based on the flame-retardant effect of halogens, and the flame-retardant principle of halogen-free cables is to extinguish the fire by reducing the temperature of the precipitated water. Fire-resistant cables rely on the fire resistance of the mica material in the refractory layer. The heat-resistant characteristics ensure that the cable works normally even in the event of a fire.
The structure and materials of the two are different. The basic structure of the flame-retardant cable is: the insulating layer adopts flame-retardant material; the sheath and outer sheath adopt flame-retardant material; the wrapping tape and filling adopt flame-retardant material.
The fire-resistant cable usually adds a fire-resistant layer between the conductor and the insulating layer. Therefore, theoretically, a fire-resistant layer can be added to the structure of the flame-retardant cable to form a flame-retardant and fire-resistant cable. This is not necessary. Because the fire-resistant layer of the fire-resistant cable is usually directly wrapped with multi-layer mica tape on the wire. It can withstand long-term burning, even if the high polymer at the place where the flame is applied is burned, it can ensure the normal operation of the line.
The main technical indicators related to the fire safety of the cable are the flame retardancy of the CO 2 cable, the density of the smoke and the toxicity of the gas. Based on the above factors, the cable flame retardant standard system includes IEC standards, UL standards, etc. Let us understand what important grade regulations are included.
