Fire Retardant Or Fire Resistant: The "Fire - Protection Code" Behind Two Cables

Fire retardant or Fire resistant: The "Fire - protection Code" Behind Two Cables

Introduction

In modern buildings and industrial facilities, fire - retardant and fire - resistant cables are crucial for the safety of electrical systems in emergencies like fires. Though both relate to fire protection, they differ significantly in concepts, structures, principles, and applications.

I. Concepts

• Fire-retardant Cable

A fire-retardant cable is one that, under specified test conditions, when burned, the flame spread is limited to a certain range after the test fire source is removed, and the remaining flames or glows can extinguish themselves within a set time. Its main role is to prevent rapid flame spread along cables during a fire, thus minimizing fire expansion.

• Fire-resistant Cable

A fire-resistant cable can maintain normal operation for a certain time under flame burning conditions. It ensures power supply to crucial loads like fire-fighting equipment, emergency lighting, and evacuation signs during a fire, emphasizing power supply in high-temperature fire environments.

II. Structural Differences

• Fire-retardant Cable

The insulating and sheathing materials of fire-retardant cables usually contain fire-retardant agents. Common ones include halogenated fire-retardant agents (e.g., chlorinated paraffin) and halogen-free ones (e.g., magnesium hydroxide, aluminum hydroxide). When heated, these agents decompose to produce flame-inhibiting substances. Halogenated agents generate halogen-containing hydrogen gases, while halogen-free agents produce water vapor, thus curbing flame spread.

• Fire-resistant Cable

The key structural feature of fire-resistant cables is the multi-layer mica tape wound between the conductor and insulating layer or among cable cores. Mica tape, with excellent high-temperature and insulating properties, can maintain insulating performance under high-temperature flames, stopping flames from reaching the conductor and ensuring normal power supply for a certain time. Some fire-resistant cables also have specially-designed sheathing materials or additional fire-protection measures, like fire-resistant outer sheaths or fire-protection tubes.

III. Working Principles

• Fire-retardant Cable

The fire-retardant principle mainly relies on fire-retardant agents. When the cable is exposed to an external fire source, the decomposed non-flammable gases or substances from the fire-retardant agents form a protective film on the cable surface. Halogenated fire-retardant agents produce hydrogen halide gases that dilute oxygen in the combustion area and inhibit combustion-reaction free radicals, slowing combustion. Halogen-free fire-retardant agents generate water vapor and solid substances like magnesium oxide and aluminum oxide, which cover the cable surface, cutting off oxygen for flame retardancy.

• Fire-resistant Cable

The working principle hinges on mica tape. During a fire, the high-temperature flame may destroy the cable's outer sheath and insulating layer, but mica tape can withstand temperatures of about 1000°C, maintaining insulating performance and structural integrity for a certain time. This prevents short-circuits between conductors or between conductors and ground, allowing current to flow and powering crucial equipment.

IV. Performance Comparison

• Fire-retardant Performance

Fire-retardant cables are categorized into different grades (e.g., A, B, C, D) based on their fire-retardant performance. Different grades have varying flame-spread distances and self-extinction times in combustion tests. Generally, they can limit flame spread speed on cables but can't guarantee normal power supply during a sustained fire.

• Fire-resistant Performance

Fire-resistant cables mainly focus on fire-resistance time. Common ones can maintain power supply in flames for 90, 120 minutes or longer under specified test conditions, depending on their design and application.

V. Applications

• Fire-retardant Cable

1. Crowded Places: In crowded places like shopping malls, theaters, hospitals, and schools, cables are widely distributed. Using fire-retardant cables can prevent rapid flame spread along cables during a fire, buying time for evacuation, reducing smoke and toxic gas from cable burning, and lowering casualties.

2. General Industrial Sites: In general industrial sites like factories and office buildings, fire-retardant cables can meet basic fire-protection requirements, preventing fire expansion from electrical circuit failures and protecting equipment and property.

• Fire-resistant Cable

1. Fire-fighting Systems: Fire-resistant cables are the first choice for powering fire-fighting equipment such as fire elevators, fire pumps, fire alarm systems, emergency lighting, and evacuation-indication systems. During a fire, these devices must function, and fire-resistant cables ensure reliable power for effective fire-fighting.

2. Emergency Power Systems: In emergency power circuits of crucial facilities like industrial sites, data centers, and high-rise buildings, fire-resistant cables are needed. When the main power fails and a fire occurs, they provide continuous power between emergency generators, UPS and important loads, ensuring the safety of key equipment and data.

Fire-retardant and fire-resistant cables are both vital in fire safety. Due to their different performance features, proper selection based on actual needs in various scenarios is essential to ensure electrical system safety in emergencies.

VI. Conclusion

YINSU Flame Retardant offers some fire retardant products suitable for wire and cable, such as microencapsulated red phosphorus fire-retardant agents FRP-950X and FRP-8050, and antimony trioxide substitute T3. FRP-950X and FRP-8050 are environmentally friendly and high efficient. They can enhance the fire-retardant performance of cables while maintaining good mechanical properties of the materials. T3, as an antimony trioxide substitute, can reduce the dependence on antimony trioxide in fire-retardant systems, offering a more eco-friendly solution. Compare with ATH or MDH, these products provide more choices for improving the fire safety of electrical systems.