The level of fire-resistant cable is higher than that of flame-retardant cable. There are significant differences in fire resistance between fire-resistant cable and flame-retardant cable, which are mainly reflected in the fire resistance time and power supply capacity.
Structural differences
The basic structure of flame-retardant cable:
(1) Insulation layer (2) Sheath and outer sheath (3) Tape and filling
The basic structure of fire-resistant cable:
A fire-resistant layer is added between the conductor and the insulation layer of fire-resistant cable. The fire-resistant layer is made of multiple layers of mica tape. Because the allowable operating temperature of different mica tapes varies greatly, the key to the fire resistance of the cable is the mica tape. Fire-resistant cable can withstand long-term burning and ensure the normal operation of the line.
Levels and characteristics of flame-retardant cable
The level of flame-retardant cable is usually divided according to its performance in flames. Common levels include A, B, C, and D. For example, Class A flame-retardant cable is required to work normally for more than 90 minutes at extremely high flame temperatures (950-1000℃) and is suitable for harsh environments with high temperature, flammability and dense personnel. The primary function of flame-retardant cables is to slow the spread of flames along the cable, thereby controlling the spread of fire. They do not emphasize continuous power supply during a fire.
Characteristics and Advantages of Fire-Resistant Cables
Fire-resistant cables, on the other hand, focus on maintaining circuit integrity in the presence of flames, essentially maintaining power supply for a certain period of time. They are generally classified into two grades: NHA and NHB. NHA-grade (highly fire-resistant) cables can withstand higher flame temperatures for at least 90 minutes without breakdown. The fire-resistant layer of fire-resistant cables is typically composed of inorganic materials, capable of maintaining its physical and chemical properties at high temperatures, ensuring the normal operation of the cables.
Compared to flame-retardant cables, fire-resistant cables perform better in fires, not only preventing the spread of flames but also providing continuous power supply during flames. This is crucial for ensuring the operation of critical equipment and personnel evacuation.
Application Selection
Due to their superior fire resistance and continuous power supply capabilities, fire-resistant cables are often chosen in applications with strict fire protection requirements, such as high-rise buildings, subways, and nuclear power plants.
Advantages and Disadvantages
Flame-Retardant Cable
Low-cost, limits the spread of flames to a certain range, and improves the fire protection level of cable lines.
Fire-Resistant Cable
Generates less acidic gas and smoke, significantly improves fire resistance and flame retardancy, and maintains the integrity of line operations. Fire-resistant cable can maintain normal power supply for a period of time in the event of a fire, while flame-retardant cable does not have this feature.
Both fire-resistant and flame-retardant cables have their own characteristics, and you can choose the appropriate cable based on the application scenario.
