BS8519 Update 2020

09 October 2020

If you are responsible for specifying, inspecting or regulating fire resistant cables for large or complex buildings then you need to be aware that the standard BS 8519 has been fully revised

Martin Boorman from Prysmian outlines some of the major changes to the guidance on selection and installation of fire-resistant power and control cables. 

Buildings are getting bigger. As their size continues to increase so too does the complexity of the active fire protection systems, such as sprinkler pumps and smoke control devices, needed to enable those inside a building to escape and to protect emergency and fire personnel. 

For these systems to continue to operate in a fire their electrical power and control cables must be able to maintain circuit integrity. Fortunately, the recently published British Standard 8519:2020 explains how such systems should be selected and installed. 

The standard identifies electrical loads defined as life safety and fire-fighting and gives specific recommendations for electrical system design for fire survival times.  

The revised standard BS8519:2020 came into effect on 30 June 2020. It replaces BS8519:2010, which has been withdrawn. So, what's new about BS8519:2020? The short answer is quite a lot.... 

Ahead of the release of our guidance PDF document, we have decided to outline the key changes in a blog. The first seven of these amendments can be found here, and in part two we will tackle the rest: 

1  Scope 

The scope of BS 8519 has been extended from life safety and fire-fighting applications to include systems which need to maintain their circuit integrity during a fire because they support critical business continuity, property protection or environmental protection functions. 

2  Normative references 

The references have been updated and expanded. 

3  Terms and definitions 

The references have been updated and expanded.  The definition of “fire-resistant cable” remains unchanged. 

4  General 

The electrical system is now required to be “verified” by a skilled person. 

5  Fire survival times 

The survival times are unchanged but for clarity the circuits are now classified as circuit category 1, 2 or 3, to align with cable categories.  The application list of Table 1 is now part of this clause.  The Table has been updated and the requirements for “Sub-main power distribution” corrected. 

6  Power supplies 

The clause has been extensively rewritten to improve clarity although the basic requirement for fire-resistant/protected primary and secondary supplies is unchanged.  Information on UPS supplies is included, based on the recommendations of BS 9991 for residential buildings.  A new Annex A is referenced for further guidance on the selection and specification of UPS/battery inverter systems.  The prime recommendation of BS 8519 for the secondary power supply remains an automatically started standby generator.  Additional recommendations for life safety generators and roof-mounted generator are included. 

Figure 1 “Example of dual supply” has been redrawn for greater clarity.  Figure 2 from the 2010 edition is no longer included as systems using a standby primary utility supply are no longer considered to be sufficiently independent and resilient. 

7  Dual circuits / diverse routes 

The clause has been rewritten to improve clarity.  Standard HV cables installed within cable protective systems are now required to conform to BS 7835.  The requirement for the degree of thermal protection is now clarified.  A requirement for LV power supplies to be installed on a dedicated support system is introduced. 

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