Key changes to BS 5839-1:2025 - Part 2

The first half of this article continues the review of key changes to BS 5839-1:2025¹, the code of practice for the design, installation, commissioning and maintenance of fire detection and fire alarm systems in non-domestic premises. It is recommended that Part 1 of the article be read first. Both parts of the article do not cover all changes, and therefore it is essential that those using the standard familiarise themselves with all the changes. The second half of the article looks to address queries that arise when the electrical installations of BS 7671:2018+A2:2022+A3:2024² (BS 7671) meet the fire detection and fire alarm systems of BS 5839-1:2025.

What are the changes?

Section 3: Limitation of false alarms and unwanted fire alarm signals

Responsibility for limitation of false alarms and unwanted fire alarm signals

The recommendations of Clause 29 highlight the need to inform the user of their responsibilities. Therefore, organizations responsible for the commissioning and/or handover of the system should advise the user that investigation of false alarms and, if appropriate, action should be undertaken at every false alarm occurrence. (Clause 29.6)

Section 5: Commissioning and handover

Handover

Prior to the system being handed over, the purchaser or representative should verify the correct number of replaceable elements and appropriate tools are incorporated for manual call points (MCPs). (Clause 40.2(d).)

A cause and effect matrix (a tool that visually represents the relationships between different inputs (causes) and outputs (effects)) or a text description of how the cause and effect operates should be provided. (Clause 40.2 (e).)

Section 6: Maintenance 

Inspection and servicing

Although service intervals are still required every 6 months, there is now an option for flexibility in that regular servicing can now take place every 5 to 7 months without the system being deemed non-compliant. (Clause 43.2.1.)

As part of the service, the control and indicating equipment (CIE), such as the control panel clock, must be verified and, if required, adjusted to ensure accurate logging of events. (Clause 43.2.10.)

In England and Wales, under the Regulatory Reform (Fire Safety) Order 2005³, the ‘responsible person’ (e.g., employer, landlord or building manager) must ensure zone plans are properly maintained and up to date. Due to the possibility that building layouts and room use may change over time, zone plans are now required to be verified over a 12-month period to ensure accuracy. (Clause 43.3.25.)

Recognizing the need for cybersecurity, the standard has added clauses outlining the need for security protocols and means of authentication to mitigate risks like data breaches or system compromises. (Clause 43.4.)

Section 7: Extensions and modifications

A new dedicated section for extensions and modifications has been introduced to the standard, while a new model certificate for extensions or modifications has also been added. (Annex G, Figure G.7.)

Extensions

It is acknowledged that the overall system might not conform to the current standard; however, when undertaking an extension to a system, any new works should conform with the current version of the standard. (Clause 45.1.)

Modifications 

Redundant equipment, such as MCPs and interfaces, can potentially cause confusion in the event of an emergency. Recognizing this as an issue, the standard recommends all redundant equipment to be removed, where practicable (not just disconnected), or clearly labelled as not in use. Ultimately, the intent of removing equipment is to ensure persons will not mistake redundant MCPs in an emergency or assume an area is protected where, for example, an obsolete fire detector is still fixed to the ceiling. (Clause 46.1.7.)

Section 8: User responsibilities

Logbook

Where a variation from the standard has been applied, for example, a fire detector placement compromise, this should be clearly stated in the logbook. Logbooks may be in digital or paper form. (Clause 48.1(h).) 

Agreed variations are now shown in the model format for the logbook. (Annex H, Figure H.6.)

The relationship between BS 7671 and BS 5839-1

BS 7671 references the BS 5839 series in several regulations, such as Regulation 101.1.3 (v), which identifies the need, in certain cases, to supplement the requirements of BS 7671 with that of other British or harmonized standards. 

Which standard takes precedence?

While Regulation 560.10 states that fire detection and fire alarm systems must comply with the relevant parts of the BS 5839 series, Clause 25.1 of BS 5839-1:2025 makes it clear that the electrical installation aspects of a fire detection and fire alarm system should be in accordance with the requirements of BS 7671.

In matters of difference between BS 7671 and BS 5839 where related to the fire detection and fire alarm system, BS 5839 takes precedence. For example, the note of Regulation 643.3.2 of BS 7671 states there are more specific requirements in respect to insulation resistance testing for wiring systems to BS 5839-1.

Are double-pole isolators required for fire detection and fire alarm systems?

When carrying out any work on a fire detection and fire alarm system, safe isolation is essential. BS 5839-1:2017⁴ removed the need for a double-pole isolator to be provided as a means of isolation for the system. However, the requirement for safe isolation remains, and this is reinforced by Regulations 12, 13, 14 and 16 of the Electricity at Work Regulations (EAWR) 1989⁵ or EAWR (Northern Ireland) 1991⁶.

Although the need for double-pole isolation was removed from BS 5839-1:2017, Regulation 462.2 of BS 7671 requires every circuit to be provided with isolation for all live conductors, except for TN-C-S and TN-S systems where the neutral or protective earthed neutral (PEN) conductor is reliably connected to Earth. Therefore, where TT systems are present, double-pole isolation is required (see Figure 1). 

Figure 1: Example of a fire detection and fire alarm system with a double-pole isolator, taken from the IET Electrician's Guide to Fire Detection and Fire Alarm Systems, 3rd Edition⁷

 

 

Who is responsible for the means of isolation?

Clause 24.1.4 of BS 5839-1:2025 places the accountability on the contractor (usually referred to as the ‘designer’ as per BS 7671) responsible for the 230 V mains power supply to ensure the means of isolation is suitable, highlighting Table 537.4 of BS 7671. However, technicians working on the fire detection and fire alarm system need to have sufficient knowledge and information of the means of isolation present on-site, as well as the necessary training, knowledge and experience to safely isolate the system. 

Should the fire detection and fire alarm system be included when undertaking the periodic inspection and testing of the electrical installation?

Any inspection and testing of the ‘functioning’ of the fire detection and alarm system should be conducted in line with the recommendations of BS 5839-1:2025, and it should be noted that periodic inspection and testing is recommended in the standard. However, inspection and testing of the ‘electrical installation,’ including the fire detection and fire alarm system, remains the responsibility of BS 7671.

Prior to conducting the periodic inspection and test of an electrical installation, the inspector is required to agree upon the extent and limitations with the person ordering the work. Documenting the extent and limitations on the Electrical Installation Condition Report (EICR) (see Appendix 6 of BS 7671) helps clarify the scope of the works, ensures transparency and helps manage client expectations. This is important, as the person ordering the work may see ‘Fire Alarm’ stated on the ‘Schedule of Test Results’ and assume the system has been fully inspected and tested (inclusive of verifying system functionality). However, it is common for an inspector to have only inspected and tested the system up to the ‘Fire Alarm Isolation Switch’ (see Figure 2). 

Figure 2: Example of an isolated fire detection and fire alarm system, taken from the IET Electrician's Guide to Fire Detection and Fire Alarm Systems, 3rd Edition

 

A ‘duty holder’, under the EAWR, is any person or organization with control over electrical systems in the workplace. For duty holders to meet their obligations under Regulation 4 of the EAWR, all systems shall be maintained. The IET recognizes periodic inspection and testing as a means of demonstrating maintenance.

The inspection and testing of the electrical installation and fire detection and fire alarm system, although interrelated, cannot always be undertaken together due to a variety of reasons, such as the competency of the inspector or time constraints. It is therefore incumbent upon the inspector as an experienced professional and competent person to make clear the extent and limitations of their work and, where required, inform the person ordering the work of the need to plan to maintain all other electrical systems that do not form part of the remit of their works. Additionally, it may be deemed prudent to suggest to the person ordering the work to involve the fire detection and fire alarm system technician in the extent and limitations discussion. At this point, it should be noted that this article in no way is suggesting that obvious defects with the fire detection and fire alarm system should be ignored. However, due to the reasons stated above, it is often difficult to fully inspect and test both systems simultaneously.

Summary

Non-domestic buildings, due to their size, complexity and potential for high occupancy, can pose increased fire risks compared to domestic buildings, while non-conforming fire detection and fire alarm systems can arise from various issues, such as insufficient maintenance, absent records, outdated equipment, and extensions or modifications without due care and consideration for the co-ordination with the existing system.

Where electrical installations encompass different systems, inspectors should be able to advise the duty holder on the boundaries of the work they will be undertaking so they can make an informed decision regarding addressing risk. Where installations are subject to inspection and testing to different standards, it is essential that only those competent to verify the installation meets the standards do so.

Staying up to date with changes to standards requires a proactive approach and level of commitment to engage with other professionals. Being informed of change aids organizations and specialists in meeting their statutory obligations, proactively managing risk, and maintaining their credibility and expertise. 

Acknowledgements

• Mark Coles
• Jon Elliott
• Leon Markwell
• Michael Peace
• Tim Benstead.
  
  

References

1.    BS 5839-1:2025 Fire detection and fire alarm systems for buildings – Design, installation, commissioning and maintenance of systems in non-domestic premises. Code of Practice.
2.    BS 7671 Requirements for Electrical Installations, IET Wiring Regulations, Eighteenth Edition.
3.    The Regulatory Reform (Fire Safety) Order 2005.
4.    BS 5839-1:2017 Fire detection and fire alarm systems for buildings - Code of practice for design, installation, commissioning and maintenance of systems in non-domestic premises.
5.    The Electricity at Work Regulations 1989.
6.    The Electricity at Work Regulations (Northern Ireland) 1991. 
7.    IET Electrician's Guide to Fire Detection and Fire Alarm Systems, 3rd Edition.