FIRE RETARDANT vs. FIRE RESISTANT CABLE

In public buildings and even private homes, cabling is the standard infrastructure for all communication, information, and power systems.

Just as cables differ depending on their intended use, they also differ depending on the particular environment within a building where they intend to be deployed.

While the basic inherent functions of the cable remain more or less the same, the outer shielding determines where it ought to be deployed.

Heat- or fire-resistant cables have special insulating material that’s different from the insulation on cables deployed in a regular environment.

For the sake of the integrity and safety of systems and occupants, respectively, building contractors, service providers, and system installers need to understand these differences, how they work, and the ideal choice to deploy in a given environment.

Heat resistant cables

Heat-resistant cables, or high-temperature cables, will operate normally at high temperatures but not in the event of an actual fire. This means that while they might not operate at 100% capacity when exposed to naked flames, they’re not susceptible to melting.

Basic cables and wires, typically used in houses and general building wiring, can only withstand temperatures ranging from 70 degrees Celsius to 120 degrees Celsius.

Depending on the material used, heat-resistant cables can continuously operate at temperatures of 260°C and even up to 370°C for short periods.

Fire resistant cables

Fire-resistant cables, otherwise known as fire-rated cables, can operate normally in the event of a fire; that is, they can continue operating without turning into fuel and propagating the fire. In short, they maintain circuit integrity during a fire.

When considering what cable to deploy in an environment with the risk of a fire, a factor to consider would be whether the cable would burn when it came into contact with the fire and whether it would contribute to further spreading of the fire.

The plastic materials used as a shield or insulating material for this type of cable can differ in constitution. Some plastics can be heat resistant but burn easily, whereas some flame-retardant plastics may not be ideal for high-temperature environments.

These cables are mostly used in scenarios where it’s imperative that systems remain operational even in the case of a raging fire to facilitate communication, marshaling, and lifesaving operations. These can include emergency power circuits for fire pumps and standby power generators, fire alarm and evacuation systems, etc.

They’re also critical in scenarios where it’s critical to prevent a plant shutdown (due to the loss of circuit integrity of the cable).

Fire retardant cables

Fire or flame retardant cables, also known as fire resistive cables, will not operate normally in the event of a fire but can actively prevent the fire from spreading.

The plastic sheathing of the cable is gauged by its degree of flammability, i.e., how easily the plastic is able to catch fire. It also gauges whether the plastic drips when it catches fire and if the drips are flaming, which can potentially spread the fire when they drip onto a surface. In the case of cables with regular sheathing, the burning plastic can be flaming hot and would likely spread the fire when it drips onto another surface.

Cables insulated with flame-retardant material can withstand a fire without turning into fuel, and if the fire is intense enough to set them on fire, they can self-extinguish if the source of the fire is eradicated.

Choice of cable for critical applications

Critical applications where the risk of fire or intense heat is high require such types of cable to help run critical operations and communications during a raging fire emergency as well as mitigate the effects of a fire.

Their insusceptibility to ignition can help avoid flame spread and afford emergency services. time to communicate, marshal, and handle a fire emergency.

They’re also deployed in plenums and cable ducts.

—