Decoding the New British Standard BS 9991:2024

The highly anticipated update to the British Standard BS 9991:2024, Fire Safety in the Design, Management and Use of Residential Buildings, has finally been published on 27th November 2024. This revised code of practice introduces significant changes to fire safety standards, emphasising enhanced protection for residential building occupants. Upon review by our UK fire team at Introba, several key takeaways stand out as significant changes in the latest iteration of the standard:

1. Scope

The updated standard clarifies its application based on the fire resistance of the building's load-bearing elements and building height. The standard now applies to buildings up to 100 metres tall with structural elements classified as A2, s1, d0, or better, while structures not meeting this classification are restricted to a maximum height of 11 metres. 

2. Stair Provision

The updated stair provision emphasises redundancy and accessibility. For buildings exceeding 18 meters in height, more than one stairway is now recommended. This change reflects a proactive approach to providing a safer and more efficient evacuation strategy for occupants to escape during a potential fire.

3. Evacuation Alert Systems

The introduction of evacuation alert systems for buildings taller than 18 meters marks a significant development. These systems, which must adhere to BS 8629, allow firefighters to have an optional means to alert and evacuate occupants as a part of a phased and controlled plan in the event of a serious fire. 

4. Sprinklers

The requirement for sprinkler systems has been expanded to include all buildings over 11 meters. Sprinkler systems in buildings over 18 meters must conform to r Category 4 (BS 9251). BS EN 12845 standards must be used in ancillary spaces over 100m2. This measure enhances fire suppression capabilities, reducing the risk of large-scale incidents.

5. Lifts

The revised standard places considerable focus on evacuation lifts, which are now a critical component of fire safety in taller buildings. Key points include:

- Each escape stairway should have an associated evacuation lift.

- Evacuation lifts should be accessed via a dedicated evacuation lift lobby or be located in the evacuation stairs; 

- Dedicated evacuation lift lobbies must be provided with smoke protection equivalent to that of the staircases.

- Lifts must comply with BS EN 81-20, while upcoming guidance in BS EN 81-76 is expected to address advanced evacuation options, such as self-evaluation.

- Buildings over 50 meters must design all lifts as firefighting lifts capable of also serving as evacuation lifts.

6. Smoke Control

Smoke control measures have been expanded as detailed below:

- Evacuation lift lobbies must be protected against smoke ingress and equipped with venting systems that do not extract smoke directly from within the lobby.

- For buildings with a top storey above 18 meters, natural AOVs (automatic opening vents) are prohibited.

- In buildings exceeding 30 meters, mechanical smoke ventilation systems or pressurisation systems must replace natural smoke shafts.

- For buildings taller than 60 meters, mechanical systems must follow pressure differential principles outlined in BS EN 12101-13.

7. Open Plan Design

The standard introduces specific limitations on open-plan designs to mitigate fire risks associated with kitchen hobs. Open-plan apartments are limited to 16 m x 12 m. Notably, sufficient distances should be maintained between cooking appliances and escape routes from habitable rooms.

A Forward-Looking Update

The BS 9991:2024 update reflects a forward-thinking approach to fire safety, aligning with evolving building technologies and societal expectations. By setting higher standards for materials, evacuation systems, and smoke control, it seeks to mitigate risks and safeguard lives in residential developments of all scales.

These revisions not only highlight the critical role of advanced fire safety measures but also serve as a reminder for developers, architects, and building managers to prioritise compliance and innovation in fire safety practices. As we move forward, adherence to these enhanced standards will play a pivotal role in shaping safer, more resilient living environments.

At Introba, our fire team is ready to help clients navigate these new standards with confidence. Leveraging our expertise in fire safety and building design, we provide tailor-made guidance to the design team and offer solutions to ensure compliance with BS 9991:2024. Our commitment to excellence and innovation ensures that your projects meet the highest standards of fire safety and functionality.