Fire & Carbon Monoxide Detection Systems in Domestic Build to Rent

1. Purpose and scope

Domestic fire and carbon monoxide (CO) detection systems are critical life-safety systems within residential properties. Their effectiveness depends on appropriate design, competent installation, suitable certified products, reliable interconnection, commissioning and ongoing maintenance.

This guide focuses specifically on detection within domestic Build to Rent (BTR) sector. It supports operators and those involved in specification, procurement, mobilisation and maintenance. It does not replace fire risk assessments, applicable legislation and standards or manufacturer instructions.

2. Legal and regulatory framework

The Smoke and Carbon Monoxide Alarm (Amendment) Regulations 2022 require relevant rented homes in England to have at least one smoke alarm on each story where there is a room used as living accommodation, and a CO alarm in any room used as living accommodation containing a fixed combustion appliance, excluding gas cookers. These regulations alone are not the complete specification for a BTR alarm system. The wider framework includes the Building Regulations, British Standards and relevant product standards.

Building Regulations Approved Document B, requires dwellings to have fire detection systems and points towards BS 5839-6. Building Regulations Approved Document J addresses combustion appliances and warnings of carbon monoxide. The operator should distinguish between the statutory minimum and the appropriate system for the specific building and its occupants by referring to BS EN 50292.

3. British Standards

Fire Detection

BS 5839-6 is the specialist code of practice for fire detection and fire alarm systems in domestic premises. It provides recommendations for the design, installation, commissioning and maintenance of systems. Establishing the required coverage, detector type, power supply and interconnection methods.

For general needs rental accommodation, the technical guide identifies Grade D1 and Category LD2 as the typical minimum approach. However, the minimum level of protection will be dependent on the building size, type, tenure and means of escape. With detection increasing to Category LD1 or potentially a Grade A systems, where there constitutes a higher fire risk. This should be confirmed for each development by a competent person and considered alongside the building design and fire risk assessment.

BS 5839-6 also references other documents that designers and specifiers should incorporate into their designs:

• BS 9991:2024 – Fire safety in the design, management and use of residential buildings
• BS 8629:2019+A1:2023 – Design, installation, commissioning and maintenance of evacuation alert systems for use by fire and rescue services in buildings containing flats
• BS 9251:2021 – Fire sprinkler systems for domestic and residential occupancies

Carbon Monoxide Detection

In domestic BTR accommodation, CO detection should be considered alongside fixed combustion appliances, flues, installation and servicing. Designers and specifiers should ensure CO alarm apparatus complies with BS EN 50291-1:2018 for performance and test methods, and BS EN 50292:2023 for selection, installation, use and maintenance in domestic premises.

Alarms may be interconnected with other CO or smoke alarms in accordance with EN 50291-1:2018, 5.13, where needed to provide early warning in sleeping rooms and areas where occupants may not hear an alarm from elsewhere in the dwelling. Otherwise, additional standalone alarms should be considered.

Mains-powered CO alarms with integral battery backup should be considered best practice in line with recent HHSRS updates, particularly where they form part of a consistent domestic fire and CO detection strategy.

4. Product selection and certification

Fire and CO alarms are life-safety products and should never be selected solely on price or appearance. BTR operators and specifiers should verify the manufacturer, model, applicable certification and compatibility of the complete system, particularly where product substitutions are proposed. Visually similar products are not necessarily technically interchangeable, so any substitution should be subject to technical review before installation. Two important checks should be made:

• Does the manufacturer or importer hold a Kitemark license in their own name?
• Does the manufacturer or importer hold a valid Certificate of Constancy of Performance (CoCP)?

Where certification is claimed, verify that it applies to the specific model being supplied. Operators should also retain evidence of the approved product specification as part of the building’s handover and asset information.

The BSI Kitemark directory provides a useful independent verification tool: https://www.bsigroup.com/en-MY/products-and-services/assessment-and-certification/validation-and-verification/

5. Avoiding unverified product substitution

A recurring risk on large BTR projects is the substitution of alarms or components after design. Products that appear visually or functionally similar are not necessarily interchangeable, as performance, interconnection, certification, compatibility and warranty may not apply to an unapproved combination.

The safest approach is to specify the compatible system and ensure any substitutions are subject to manufacturers’ instructions before installation. Where a product substitution or change is proposed, compatibility and certification should be checked before installation rather than relying on physical fit or apparent functionality.

6. Golden thread – Installation, commissioning and maintenance

The complete system should use compatible components and be tested after installation. Where the design calls for multiple alarms within a property these should be interconnected, to operate together. The installation should comply to BS 7671:2026, which also stipulates under Chapter 56 (Safety Systems and Services) regulation 560.10 that fire alarm and detection systems shall comply with the relevant parts of BS 5839.

Operators should maintain commissioning records identifying the grade and category of system along with any variation/deviations within the system. Along with records of alarm locations, models numbers, installation dates, expiry dates, interfaces with other systems (Sprinklers, Ventilation, etc) and certification.

A planned testing and maintenance regime should be established by the operator, with further investigation into nuisance alarms, faults, repairs and replacements. On occupational PEEPs and PCFRAs should be undertaken promptly when an individual’s needs may affect their ability to evacuate safely and reviewed whenever their circumstances or needs change.

8. Resident communication

Residents should receive clear information on start of tenancy explaining the purpose of the alarms, how to test them, what to do if an alarm activates and how to report faults or damage. Regular user testing is required as per Table 3 of BS 5839-6.

9. Conclusion

Good domestic BTR fire and CO detection is about maintaining a reliable life-safety system throughout the property’s operational life. Best practice means establishing the required protection, specifying verified compatible products, controlling substitutions, commissioning the complete system, retaining accurate records and managing testing, maintenance and resident communication.

References

• Smoke and Carbon Monoxide Alarm (Amendment) Regulations 2022
• Approved Document B – Fire Safety, Volume 1: Dwellings
• Approved Document J – Combustion appliances and fuel storage systems
• BS 5839-6:2019+A1:2020 – Fire detection and fire alarm systems in domestic premises
• BS 9991:2024 – Fire safety in the design, management and use of residential buildings
• BS 8629:2019+A1:2023 – Design, installation, commissioning and maintenance of evacuation alert systems for use by fire and rescue services in buildings containing flats
• BS 9251:202 – Fire sprinkler systems for domestic and residential occupancies
• BS EN 50291-1:2018 – Carbon monoxide detectors for domestic premises
• BS EN 50292:2023 – Guidance on selection, installation, use and maintenance of CO detection equipment