This informal CPD article ‘Strengthening Fire Safety – Updates to BS5839-1:2025’ was provided by Jade Masefield of OpenView Security Solutions, an independent security company providing unique, innovative solutions to meet individual client needs in both the private and public sectors.
It is a legal requirement for all UK businesses, public and commercial, to have a suitable method of detecting fires and alerting people on site, and the UK government advises that all fire alarm systems should be installed and maintained in line with the relevant British Standards, such as the BS5839-1:2025 and the BSEN54. (1) Most fires are preventable, but even with the most thorough risk assessments and control measures in place, the odds of a fire breaking out are never zero. This article will serve as a refresher on key fire safety principles and the update of BS5839-1:2025.
The Ongoing Mission for Safer Buildings
Fire safety standards are constantly evolving to comply with new regulations put into place for occupant safety, property preservation, insurance requirements, and professional credibility. Before electricity was discovered, societies would often combat fires as and when they broke out, meaning reaction times were incredibly slow. In the 17th century, police hired men to walk the streets with buckets of water, looking for fire. In the 1800s, bell towers were being utilised as city-wide fire alerts. Fast forward to now, we have intricate systems in place that give us early warning of a fire. These improvements are not only technological advancements; they’re the result of learning from past events. This is why we are still actively updating legislation today.
Fire Detection and Alarm Systems
A fire alarm system can be defined as a network of interconnected devices and components designed to detect, signal, and provide early warning of a fire or an emergency. The Regulatory Reform (Fire Safety) Order 2005 requires that a responsible person must lead the installation and maintenance of fire alarm systems, including regular weekly testing as per BS5839 standards. (4) This involves activating at least one call point each week, verifying the system’s audibility. This person must also maintain a log of all tests and inspections for compliance, insurance, and safety verification purposes.
Following this, a full service of fire detection and alarm systems by a competent professional is required every six months to remain compliant with BS5839-1:2025 (1). A competent person/professional is someone that is considered to have had the necessary combination of training, knowledge, and experience to perform a task safely and effectively. This individual has a significant role to play in early warnings, evacuation, and life protection.
Think of an alarm panel as the brain of a system. It monitors devices such as manual call points and smoke detectors. It processes the information and activates the system’s alarm, and other functionalities. For an alarm panel to be able to function effectively, it must have signal reception, signal analysis, response initiation, communication with notification devices, and system monitoring. This is all done using electricity. Therefore, if there is an electrical failure in the building that results in the power going out, fire alarm panels have a standby back up battery in which they operate off temporarily until the power is restored.
Fire alarm panels should be situated on the ground floor, near the building’s entrance, where there is a minimal risk of fire breaking out. It should also be easily accessible, and it should be visible from the outside of the building. The top of the panel should be approximately 1.65 meters above the floor. (2) There are two types of control panels: conventional (non-addressable) and addressable. Conventional panels divide a building into zones that are associated with a specific area. When a detector in a zone is triggered, the control panel can identify the general location of the alarm, but not the specific location of the device. These are often installed within smaller buildings where a basic level of fire detection is sufficient. Addressable control panels assign a unique address to each detector and device on the system. This allows the system to precisely identify the location of an alarm and provide detailed information to emergency responders. These panels are more suitable for larger and more complex establishments where pinpoint accuracy is crucial for an effective response.
Smoke detectors are a type of alarm that quickly identify smoke which indicates that there is a fire nearby and will then give off a loud signal to warn of danger. Each smoke detector must have a clear space of 500mm in all directions around and below them. (2) There are two methods smoke detectors use: the ionization method, and the photoelectric method. Ionization is useful for detecting fast burning, flaming fires in residential settings due to radioactive material that ionizes the air. The photoelectric method is useful for detecting slow-burning, smoldering fires. Understanding the difference between the types is crucial to them being installed into the correct environments. Not every room is required to have a smoke alarm, but they are mandated in certain areas - they should be installed in spaces where people work or frequently move through.
Manual call points are bright, red boxes attached to the wall that allow you to manually trigger a building’s fire alarm system. They are installed in accessible locations in which they should be unobstructed and clearly visible. They enable for a quick response to fire, sometimes before automatic detectors have been activated. Triggering a manual call point will sound an alarm and trigger visual alarms throughout the building.
The number and placement of fire detection devices depend on the building’s size and layout, the nature of the business, and the building’s fire risk assessment. It’s considered best practice to have interlinked fire alarms for commercial premises, and in compliance with BS5839-1:2025, all buildings with a fire alarm system must maintain an up-to-date and accurate fire alarm zone plan that is correctly oriented and shows specific topographic information as well as the division of the building into fire detection zones. (8) This needs to be positioned next to your fire alarm control panel and any repeater panels. Once you have installed a fire alarm system that is legally compliant, it is your duty to maintain and ensure its continued functionality.
Categories for fire alarm systems
Categorisation of Fire Alarms: (L)ife Protection, (P)roperty Protection, and (M)anual
Life protection, property protection, and manual are categories for fire alarm systems defined by BS5839-1 standards, based on the level of life and property protection coverable. (1) Manual systems rely on human activation. Life protection systems use automatic detection to optimise chances of early evacuation. Property protection systems use automatic detection to protect the building or its contents.
Life protection systems:
- L1: Highest level of life protection. Automatic fire detection is installed in all areas of the building.
- L2: Provides automatic detection in all areas specified in an L3 system, with the addition of high-risk areas.
- L3: Standard life protection. Automatic fire detection is in escape routes and in all rooms connected to them to provide early warning.
- L4: Modest life protection. Automatic detection is installed only within the escape routes of the building, such as corridors and stairways.
- L5: Localised life protection. A specific-risk system where automatic detection is only installed in a particular area.
Property protection systems:
- P1: Maximum property protection. Automatic fire detection is installed throughout the entire building.
- P2: Minimum property protection. Automatic fire detection is installed only in specific areas.
Manual operation systems:
- M: Manual fire alarm system. This system relies entirely on manual activation via manual call points (break glass). Only suitable for premises where a fire is likely to be discovered and reported quickly by occupants.
These fire alarms are categorised based on the level of protection they offer. The required sound levels are at least 65 decibels to ensure audibility. In high-noise areas, louder alarms may be necessary. Sleeping areas require a minimum sound level at bedhead to wake sleeping occupants. The fire alarm sound must be distinct from other noises throughout the building to ensure immediate recognition.
Fire detection and alarm systems play a significant role in early detection and the rollout of emergency response plans. Triggering an alarm at a fire’s earliest stages gives a better chance of survival.
Preventative Measures and Fire Risk Management
A fire detection system is fundamental for conducting effective fire drills and training exercises. The practical element helps to familiarise people with the alarm sound and evacuation procedures in place.
The most common fire prevention measures are:
Electrical safety (7) - avoid overloading sockets, check that your equipment is functioning correctly, use proper chargers with the correct watts and voltages, and inspect the wiring.
Housekeeping (7) - keep spaces as tidy as possible and free of clutter, store flammable materials away from heat sources, clear escape routes, maintain cooking areas – don’t let grease build up.
Heating and Smoking (7) – don’t cover heating equipment, make sure it’s stable and can’t be knocked over. Smoke safely, and only in designated areas, dispose of cigarettes properly, and never smoke in bed - even with fire retardant covers.
Emergency Preparedness (7) – install and maintain functionality of smoke alarms, refer to evacuation procedures to plan escape routes, and perform regular inspections.
Employers must carry out a fire safety risk assessment and keep it up to date. Based on the findings, employers also need to ensure that adequate and appropriate fire safety measures are in place to minimize injury or loss of life in the event of a fire. It is a legal requirement for businesses to have regular fire risk assessments, an appropriately trained person of responsibility, the correct fire extinguishers, safety signs for fires in the appropriate areas, fire marshals and fire wardens, fire safety training for teams, dedicated fire systems, emergency lighting, and fire doors. (4)
Grenfell Tower had ‘stay put’ fire policy
The Grenfell Tower Tragedy – A Turning Point for Fire Safety
Another significant factor in preventative measures is building design and material choice, which prevents the rapid spread of fire. An example of this is Grenfell Tower:
Grenfell Tower was originally built in the 1970s, in West London, and recently underwent refurbishment in 2016. In the early hours of June 14th, 2017, a fire broke out in the kitchen of a flat on the fourth floor that started on or around a fridge freezer. (5) According to a witness report, a smoke alarm sounded and awoke an occupant, who called emergency services at 00:54am. The fire service arrived five minutes later and gained access to the building. They entered the room of the source of the fire at 01:14am. By this time the fire had already broken out of the kitchen window and spread backwards to one of the bedrooms. As it grew it became external to the building (it is suggested that the fire had already spread to the cladding prior to the firefighters entering the kitchen). From the fourth floor, the fire quickly spread upwards and across the eastern side of the building; from there it spread across the north face of the tower. To put it into perspective, the blaze reached the top floor of the east side in just thirty minutes. By 02:00am, the fire was declared a major incident. (5)
Grenfell Tower had a ‘stay put’ fire policy in place. The building was supposed to be designed to contain a fire in a single flat until it could be controlled by emergency services, however long that may be. Therefore, emergency services instructed residents to remain in their flats, in which they later became trapped. It was clear that the policy had failed and was abandoned at 02:47am. By this time, the escape routes were already filled with thick smoke. Some residents sought refuge with their neighbours who lived on upper floors of the building, whilst others ignored the instructions and evacuated themselves. 144 people managed to evacuate before 01:38am, but only 36 after the stay put guidance was abandoned. 72 people died in total. (3)
Looking back at the renovations made a year prior, the most significant part was the addition of external cladding; the material was made up of aluminum sheets bonded to a central plastic core. It’s theorised that the polyethylene material in the cladding was the primary cause of the fire’s spread. (3) Combustible materials used for the tower’s windows and exposed gas pipes that were installed were also factors that contributed to the spread of the fire.
Flammable materials, including a polyurethane polymer foam insulation board were also present before any renovations taking place were also a possible contributor, (3) linking into the Fire Tetrahedron – when a fuel source reaches the right temperature, the chemical reaction becomes self-sustaining, making consequent chemical reactions escalate so that an external ignition source is no longer needed to keep the fire going.
Upon further inspection, the building’s smoke extraction system was found to not be in working order, and firefighters discovered there was no wet pipe (a water-filled pipe that runs up a building that is used in the event of a fire). None of the flat doors met current fire resistance standards, and work completed on the lifts meant they were unfit for evacuation purposes, leaving vulnerable residents with no escape route. (3) The blaze didn’t burn itself out until a day later.
The Grenfell Tower tragedy highlights the significance of having a functional, well-maintained fire safety system, effective evacuation procedures, and appropriate building design. Incidents such as Grenfell have accelerated the review and strengthening of fire safety standards across the UK. Although the updates to BS 5839-1:2025 were not made directly in response to the Grenfell fire, such events have acted as catalysts for change, reinforcing the importance of regularly reviewing and improving fire safety measures. The 2025 revision reflects this ongoing commitment to continuous improvement in fire safety to help prevent similar large-scale incidents and loss of life.
B55839-1:2025 Fire Detection and Alarm Systems for Non-Domestic Buildings
BS5839 is a collection of British Standards that offer guidance on the design, installation, commissioning, and maintenance of fire detection and alarm systems in buildings. (1) It’s an essential reference for providing optimal protection for occupants and properties.
BS5839-1:2025 specifically addresses non-domestic premises and serves as a key standard for commercial businesses. Office buildings, retail, industrial properties, hospitality, healthcare facilities, educational buildings, and transport facilities are all examples of non-domestic buildings. It covers: the types of systems and components to be used, the positioning of detectors and alarms, the extent of coverage and zoning, control and indicating equipment, power supplies, installation and cabling, and testing and maintenance procedures. (1)
What’s Changed? (New Clauses)
- Restructuring of clauses:
Clause 4 is moved to the Introduction. Clause 33 is merged with Clause 31. (6) - New section 7 added to address extensions and modifications. (6)
- Tighter controls on variations: certain deviations from recommendations are now explicitly prohibited in Clause 6 due to safety concerns following fatal fires. (6)
- Simplified siting recommendations for manual call points. (6)
- Improved guidance on fire detection in sleeping areas: preferring automatic fire detection over heat detectors or sprinkler heads in rooms where people sleep. (6)
To simplify this, if people sleep in a room, the standard now requires smoke detectors to be used instead of heat detectors. Slight deviations from the recommended designs are no longer permitted for safety reasons; previously, designers could freely deviate if justified. Any changes made must now be fully justified, documented, and recorded in the logbook.
The updated standard also introduces a new section covering modifications and extensions to existing alarm systems, ensuring that any system alterations meet current safety expectations. All key documentation must be kept up to date and follow the new format in place, while maintenance visits now require additional checks to verify system reliability.
There are also new rules regarding signal transmission times to reflect the growing use of digital and networked systems. Finally, the clause layout has been made clearer, with some sections moved and combined to improve readability and consistency throughout the standard.
Conclusion
In conclusion, the continued development of safer procedures surrounding fire safety are essential to protecting life, property, and preventative measures. Catastrophic events have highlighted consequences of inadequate systems and complacency. By updating regulations and abiding by them, we are promoting consistency, technological adaptability, and strengthening the foundations of fire safety management across all types of buildings. Let’s ensure that lessons from the past are driving safer outcomes in the future.
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References
- (1) BS 5839-1:2025 Fire detection and fire alarm systems for buildings – Code of
- practice for design, installation, commissioning, and maintenance.
- (2) BS 9999:2017 - Code of practice for fire safety in the design, management, and use of buildings.
- (3) The Grenfell Tower Inquiry Reports (Volumes 1–3).- UK Government Publications
- (4) The Regulatory Reform (Fire Safety) Order 2005 and amendments.
- (5) Grenfell Tower: What happened - BBC News
- (6) BSI Knowledge Portal - https://knowledge.bsigroup.com/products/fire-detection-and-fire-alarm-systems-for-buildings-design-installation-commissioning-and-maintenance-of-systems-in-non-domestic-premises-code-of-practice
- (7) UK Government Fire Safety Risk Assessment – 5-Step Checklist https://www.gov.uk/government/publications/fire-safety-risk-assessment-5-step-checklist/fire-safety-risk-assessment-5-step-checklist-accessible
- (8) Technical Bulletin
Technical-Bulletin-A-guide-to-fire-detection-and-fire-alarm-system-zone-plans.pdf
