Core Difference Comparison
Understanding the distinction between flame-retardant and fire-resistant cables is essential for choosing the correct type for fire safety scenarios. The following table compares these two cable types across key attributes:
Attribute | Flame-Retardant Cable (ZR) | Fire-Resistant Cable (NH) |
---|---|---|
Fire Protection Objective | Prevent flame spread | Maintain circuit integrity under fire |
Testing Standard | GB/T 18380, IEC 60332 | GB/T 19216, BS 6387 |
Temperature Resistance | Up to 750°C briefly | Up to 950–1000°C for 90–180 mins |
Insulation Material | PVC, LSZH | Mica tape + XLPE or similar |
Smoke & Toxicity | Low with LSZH | Low with LSZH + Mica |
Typical Applications | Public spaces, basic power lines | Emergency systems, fire pumps, alarm circuits |
Selection Logic for Fire Safety Scenarios
When selecting cables for fire protection, the key question is whether the cable must continue functioning during a fire. In critical systems like fire pumps, smoke exhaust fans, emergency lighting, and fire alarms, **fire-resistant cables (NH type)** are essential due to their ability to sustain circuit integrity under extreme heat. This ensures life-saving systems remain active during evacuation.
Conversely, **flame-retardant cables (ZR type)** are sufficient where cable operation during a fire is not required, but it is crucial to prevent the spread of flames. This applies in general distribution circuits, public areas, and vertical shafts where flame propagation control is vital. LSZH (low-smoke zero halogen) variants are recommended for enclosed, high-occupancy buildings to reduce toxic smoke during a fire.
Key Performance Test Comparison
Test Item | Flame-Retardant Cable | Fire-Resistant Cable |
---|---|---|
Flame Test | IEC 60332-1/3 | IEC 60332-1/3 |
Fire With Power | Not required | BS 6387 CWZ |
Smoke & Halogen Test | IEC 61034, IEC 60754 | IEC 61034, IEC 60754 |
Selection Decision Tree
Application Examples
Fire-resistant cables are widely used in metro systems and fire alarm loops; flame-retardant cables are often installed in office buildings, hospitals, and shopping centers for general power supply and lighting systems.