Fire rated, fire resistant, or fire performance cables?

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. 

 

 

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.