Fire rated, fire resistant, or fire performance cables?

 

 

When it comes to cables, we often hear the terms 'fire resistant,' 'fire rated,' and 'fire performance,' but which is correct? 

 

 

The topic of fire safety, particularly in buildings, has rarely been out of the news in recent years. Since the Grenfell tragedy in 2017, it has become an even bigger concern for the construction industry. 

  

Developing fire performance cables is a key focus for expert cable manufacturers to ensure fire safety in buildings. Electrical professionals responsible for specifying or installing power cables know they must ensure that the right cable systems are in place. 

 

‘Fire rated cables,’ ‘fire resistant cables,’ and ‘fire performance cables,’ are terms we often hear. However, we find the terms are commonly interchanged which may lead to a lack of clarity in discussion, specification or installation. Knowing the differences between these terms can be crucial.

 

 

The term ‘fire rated’ is commonly used when discussing fire safety cables, however, its definition is not very clear. Fire rated cables could have fire resistance, be standard or enhanced, have low smoke zero halogen (LSOH) insulation or PVC insulation that is UKCA marked to the requirements set out in the Construction Products Regulations (CPR). In other words, ‘fire rated’ doesn’t say explicitly what it is, but what it might have. 

  

What do we mean by ‘fire resistant?’ Here at Prysmian, we mean a cable that is able to ‘resist’ fire and retain circuit integrity at a defined flame temperature and time, as well as impact and water spray regime. This ensures that vital systems such as fire alarms or emergency lighting systems continue to function as designed. 

 

Fire resistant cables feature a copper conductor and they also require a low smoke zero halogen (LSOH) sheath. General wiring cables typically have a cable sheath made from other components such as PVC, which can produce toxic fumes, thick, black smoke and acid gas in a fire. This is a risk to public health and emergency equipment, whereas LSOH cable sheaths produce very low levels of smoke and no acid gases. 

 

Fire performance cables 

 

Our Fire performance cable range, known as FP cables, is the original, easy to install and fully compliant fire safety cable range. When Prysmian use the term fire performance cables, we use this as an all-encompassing term for cables with fire resistant properties.

  

Fire resistant cables are specifically designed to maintain circuit integrity and continue to work for a specific time under defined conditions for 30, 60, or 120 minutes. This means that even though cables are significantly affected, they continue to work. Fire resistant cables can also help prevent the passage of fire and smoke from one area of a building, duration a specific time period.

  

It is essential that life safety systems and fire fighting systems continue to operate in order for occupants to evacuate a building, this includes maintaining power to ‘refuge’ areas where disabled users can go to await safe evacuation. Once in these areas, staff can activate Refuge Area Remote Unit, which allows the Fire Officer to communicate with them. For these systems to continue to operate in a fire, their electrical power and control cables must be able to maintain circuit integrity. 

  

The British Standard BS 8519 explains how such cables should be selected and installed and identifies electrical loads defined as life safety and fire fighting and gives specific recommendations for electrical system design for fire survival times.  

 

BS 8519 defines life safety systems as those that must remain operational to alert, evacuate and protect people. Cables should fall under either Category 1 (30 minutes survival time) or Category 2 (60 minutes survival time).

 

Fire fighting systems refer to active systems for protecting and assisting fire fighters. Typically, these cables should meet the requirements of Category 3 (120 minutes survival time), but some systems need to meet requirements of Category 2. 

 

Additionally, BS 5839-1 and BS 5266-1 specifies that these fire resistant cables meet the requirements of 'standard' fire resistance or 'enhanced' fire resistance.

  

‘Standard’ fire resistant cables are required to meet a survival time of 30 minutes when tested to BS EN 50200 (PH 30); and a survival time of 30 minutes, when tested to BS EN 50200 Annex E—which is exposure to fire, impact, and water spray.

  

‘Enhanced’ fire resistant cables, on the other hand, are required to meet a survival time of 120 minutes when tested to BS EN 50200 (PH 120); and a survival time of 120 minutes when tested to BS 8434-2 – which is a longer, hotter test than Annex E. This is essential for applications relating to un-sprinklered buildings.

 

Prysmian fire performance cables FP200 GOLD and FP PLUS are required to meet the ‘standard’ or ‘enhanced’ fire resistance requirements. 

  

When you choose Prysmian FP cables you choose cables that are approved by engineers, installers and regulators. Prysmian’s FP range is more than a cable, its reliability at its core. Prysmian are the market leaders for fire performance cables, this is the result of 50 years of continuous development.

  

   

Prysmian has been researching and developing high-quality, efficient fire performance cables for many years. This is even before cable specifications BS 7629-1 and BS 7846 came into effect. 

 

FP cables are part of our long-term development of the next generation of fire resistant cable. They are not only designed to help save lives in a fire but also provide greater property protection. It is the fully compliant fire safety cable range that has been approved by engineers, installers, and regulators.

 

Prysmian FP200 GOLD is the most common ‘standard’ cable solution for fire detection and fire alarms and features fire resistant and flame retardant properties. It achieves a minimum of 30 minutes survival time in flame and impact, plus an additional requirement for water spray. It is easy to install and terminate. 

 

FP PLUS falls under the ‘enhanced’ category. FP PLUS is an ‘enhanced’, hard skin, fire resistant cable that is commonly used in large, complex buildings such as hospitals, for fire alarm and emergency lighting systems. It is also used for emergency voice communications and alarms, escape lighting, and control circuits for fire safety. 

  

Prysmian FP600s is our ultimate fire resistant, armoured cable. It is designed for power and control of life safety and fire-fighting systems used in buildings. Its applications also include powering smoke barriers, smoke and heat exhaust ventilation systems, and extinguishing systems such as sprinkler pumps. 

 

We have been at the centre of cable fire resistance for decades, so for reliability at its core, choose Prysmian FP cables.