How do FP cables work during a fire?
Fire performance cables are critical in helping to save lives and provide greater property protection. So, how do they contribute to safer buildings?
The potential for a fire is always present. Latest Government figures (published January 2024) show that Fire and Rescue Services (FRS) attended over 143,000 fires in the year ending September 2023.
When the worst happens, the primary objective must be to preserve life – which means that emergency alarms, lighting, sprinkler systems and the like must continue to work even as fire is raging through a building and most electrical equipment fails. A separate, robust infrastructure of fire-resistant cable is required by British Standards Codes of Practice listed in Building Regulations Approved Document B. The documents provide guidance on fire safety in buildings, Volume 1 covers dwellings and Volume 2 covers all other types of buildings. The FP range from Prysmian includes cables with different fire ratings for different applications.
Emergency lighting for building evacuation
Typically, the first sign indicating that there is a fire in a building is the sound of the fire alarm showing that the detector circuits have functioned. Should normal lighting fail following a loss of power, the maintained and non-maintained emergency lighting system kicks into action. Emergency lighting is designed to illuminate escape routes and emergency exit signs to help all occupants evacuate the building. Emergency lighting is a requirement of The Regulatory Reform (Fire Safety) Order 2005.
FP200 Gold is a “Standard” fire resistant cable specifically designed to meet the requirements of BS 7629-1 as necessary for fire detection, fire alarm and emergency lighting systems in buildings. “Standard” fire resistant cables are required to achieve at least 30 minutes circuit integrity when tested in accordance with BS EN 50200 and BS EN 50200 ANNEX E. This makes FP200 Gold ideal for shops, offices, and schools, where the route to the exit is short and clear.
For hospitals or large, complex buildings where it may take longer than 30 minutes to evacuate, or if there is a need for multiple phases of evacuation, i.e. for wheelchair users who need time to get to a designated area, FP PLUS may be a better choice. FP PLUS is an “Enhanced” fire resistant cable specifically designed to meet the requirements of BS 7629-1, as necessary for fire alarm and emergency lighting in buildings. “Enhanced” fire resistant cables are required to achieve at least 120 minutes when tested to BS EN 50200 and BS 8434-2.
Preventing the spread of fire
Once the occupants of the building have been evacuated, the systems designed to support fire fighting take over. These include sprinkler pumps, smoke and heat exhaust ventilation systems (SHEVs) and fire-fighting lifts. It is essential that the fire-resistant cables used in these systems maintain circuit integrity for even longer in these really challenging conditions. For these power applications, FP600s is the ideal choice.
FP600s is a steel wire armoured power cable with fire-resistant properties that is manufactured in accordance with BS 7846, achieving the highest fire performance rating, F120. The cable also meets BS 8491- 120 Minutes Fire Resistant Test which is Flame, Direct impact & Water JET applied to cable at its minimum bend radius. FP600s is ideal for SHEVs, disabled refuge areas, fire-fighting and evacuation lift supplies, smoke barriers, control dampers and smoke curtains plus extinguishing systems such as sprinkler pumps, water mist and powder.
Another cable for specific applications is FP500. This is designed to satisfy Cat 3 Control Cable requirements for BS 8519 for life safety and fire-fighting systems. FP500 cables are part of the control circuitry of a particular fire-fighting system that is required to operate when a fire is detected. This includes life safety and fire-fighting equipment such as, evacuation route pressurisation, sprinkler pumps and SHEVs – FP500 cables do not distribute power, they carry the signal to initiate the fire-fighting equipment.
Finding the right cable
Fires in buildings are not unusual and emergency control and evacuation systems are continually evolving to further reduce the danger to life and damage to property. Specifying non-fire resistant cable has the potential to become the weakest link of such systems, so understanding the range of high-performance, rigorously tested cable options is an essential part of any fire prevention strategy.
Learn more about the full range of FP cables.