Fire resistance vs flame retardance
There is a fundamental difference between fire resistant cable and flame retardant cable. Let’s look at the details here.
Ensuring fire safety in public buildings is a high priority, and one important aspect to consider is the type of cable used in life safety, fire-fighting, and evacuation systems. Both fire-resistant cables and flame-retardant cables are used, but they serve different purposes. Let's explore these differences.
What’s the difference between fire resistant cables and flame retardant cables?
Both types of cable play an important part in helping to improve the chances of escape and survival during a fire and are sometimes mistaken to be the same cable. However, there is a fundamental difference between flame retardant cables and fire resistant cables.
- Flame Retardant Cables: Designed to slow down the spread of fire into new areas.
Fire Resistant Cables: Specifically designed to maintain circuit integrity and continue to work during a fire under defined conditions, to help the people evacuating, and those fighting the fire.
When flame retardant cables should be used
The fire performance of flame retardant cables is limited to not propagating fire, releasing very limited amounts of smoke and acid gases. Flame retardant cables slow down the spread of fire thanks to its self-extinguishing materials within the design that reduce the propagation of flames. These cables are not designed to function during a fire and are likely to fail. Flame retardant cables are ideal for non-emergency circuits because as well as reducing the spread of fire, smoke and toxic gases in the building, they distribute energy to ordinary sockets and lighting e.g., printers, kettles and TVs, devices that are not required during a fire. However, fire resistant cables will continue to distribute energy and signals at at least 8500C for half an hour or more.
When fire-resistant cables should be used
Fire-resistant cables should be used in a building to provide circuit integrity for emergency systems such as fire alarms, emergency lighting and sprinkler pumps. How long the cables need to maintain their circuit integrity, depends on their application. “Standard” fire resistant cables are required to achieve at least 30 minutes circuit integrity when tested in accordance with BS EN 50200 AND also tested to BS EN 50200 ANNEX E. “Enhanced” fire resistant cables are required to achieve at least 120 minutes when tested to BS EN 50200 AND also to BS 8434-2. Fire detection and fire alarm circuits in standard buildings require minimum 30-minute direct flame tests with simultaneous indirect impact and water spray. Life safety and fire-fighting systems for large and complex buildings on the other hand, require a higher temperature flame for longer with more arduous direct impact and water-jet tests. These cables are required to survive for 120 minutes.
Choosing the Right Cable for Fire Safety
When selecting cables for fire safety, it's crucial to understand the differences and applications of fire-resistant and flame-retardant cables.
The Prysmian fire performance cable range is the result of almost 50 years of continuous development of cables for fire alarms, emergency lighting, life safety and fire fighting systems. Making them the ideal choice when choosing a reliable and trusted cable. Not only are they manufactured by Prysmian in the UK but they are also examined and certified to a range of tests that assess circuit integrity in the event of fire to help save lives and protect property.
Each Prysmian cable serves a specific purpose, which is important to note when selecting the right fire performance cable for a building, as they can save lives. The most commonly used cable in the range is Prysmian FP200 Gold – a “Standard” fire resistant cable specially designed to meet the requirements of BS 7629-1 for fire detection, fire alarm and emergency lighting systems in buildings. It is the ideal choice for factories, offices, schools and shops. For large or complex buildings such as hospitals, “Enhanced” fire resistant cable is required. For this, FP PLUS is the ideal choice.
Life safety and fire-fighting systems are required for large or complex buildings including skyscrapers, hospitals or shopping centres. Prysmian FP600s is ideal to power life safety and fire-fighting systems including fire-fighting lifts, smoke and heat exhaust ventilation systems and sprinkler pumps – all of which require greater fire performance from cable compared to everyday fire alarm and emergency lighting systems. Prysmian manufacture FP600s at its UK factories in compliance with BS 7846 achieving the highest fire performance rating, F120.
The latest cable in the Prysmian Fire Performance cable range is FP500. FP500 is designed to satisfy CAT 3 Control cable requirements for BS 8519:2020 including where the control cable is to be used as a single phase power cable. FP500 is steel wire armoured (SWA) which makes it the ideal choice because mechanical protection is required. The galvanised steel armour wires ensures that there is no need for additional mechanical protection as it is already built into the cable.
Ongoing Research and Development
Prysmian continues to invest in the research and development of high-quality, efficient fire performance cables. We are proud to share that expertise and understanding through our technical seminars. Prysmian technical seminars focus on the reaction-to-fire and fire-resistance of cables, to enable engineers, designers and installers to make the all-important decisions. Find out more and register your interest today.