1 The difference in principle
Fire-resistant cables have different principles from flame-retardant cables. The flame-retardant principle of halogen-containing cable is based on the flame-retardant effect of halogen, and the flame-retardant principle of halogen-free cable is to reduce the temperature of the water to extinguish the fire. Fire-resistant cables rely on the fire-resistant and heat-resistant characteristics of the mica material in the fire-resistant layer to ensure that the cable works normally even in a fire.
2 The difference between structure and material
The structure and materials of fire-resistant cables are different from those of flame-retardant cables.
The basic structure of flame retardant cable is:
(1) The insulating layer is made of flame-retardant materials
(2) Flame-retardant materials are used for the sheath and outer sheath;
(3) The wrapping tape and filling are made of flame retardant materials.
Fire-resistant cables usually add a fire-resistant layer between the conductor and the insulating layer, so 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 of the fire-resistant layer of fire-resistant cables, multi-layer mica tapes are usually used to wrap the wires directly. It can withstand long-term combustion, even if the polymer at the place where the flame is applied is burned, it can ensure the normal operation of the line.
3. What is the difference in the structure of flame-retardant, fire-resistant, and flame-retardant fire-resistant cables?
The structure of flame-retardant cables is basically the same as that of ordinary cables. The difference lies in its insulating layer, sheath, outer sheath and auxiliary materials (wrap tape and Filling) all or part of the flame-retardant material is used, and the fire-resistant cable usually adds a fire-resistant layer between the bare conductor and the insulating layer. Therefore, theoretically, a fire-resistant layer can be added to the structure of the flame-retardant cable to form Both flame-retardant and fire-resistant cables, but this is not actually necessary. Because of the fire-resistant layer of fire-resistant cables, multi-layer mica tapes are usually directly wrapped on the wires. It can withstand long-term burning. Even if the high polymer at the place where the flame is applied is burned, the normal operation of the line can be guaranteed.
4. What is the difference between low-smoke and halogen-free cables, low-smoke and halogen-free fire-resistant cables and low-smoke and halogen-free flame-retardant and fire-resistant cables?
As the name suggests, it is the difference in sheath materials. Low-smoke and halogen-free is environmentally friendly, that is, it does not produce a large amount of toxic gas during combustion, which ensures the safety of relevant places. Fire resistance means being able to stay in the flame without melting. Ordinary is a general sheath material.
5. The classification principles of flame retardant a, b, and C levels and what is the difference in structure are divided according to standard regulations. They are used to evaluate the ability of vertically installed bundles of wires and cables or optical cables to inhibit the vertical spread of flame under specified conditions：
Flame retardant Class A refers to: the cable is installed on the test steel ladder so that the total volume of the non-metallic materials contained in the test is 40 minutes, and the cable is burned to dry the sample. The maximum carbon circumference of the test sample shall not be higher than the bottom resistance of the blowtorch.
The flame-retardant type B cable is installed on the test steel ladder so that the test material in the total volume is the burning and drying test sample, and the maximum carbon circumference of the test sample shall not be higher than the bottom of the blowtorch
The flame-retardant type C is installed on the test steel ladder so that the total volume of the non-metallic materials in the test is 5/m, and the fire time is 20 minutes. After the cable burning stops, dry the sample, and the maximum carbonization of the sample is measured. Not higher than the bottom of the blowtorch