If you work around residential developments, apartment buildings or smoke ventilation systems, you have probably come across the term BS 9991.
It is one of the key fire safety standards used in residential building design and has become increasingly important on modern apartment and high-rise developments.
BS 9991 provides guidance on how residential buildings should be designed to help protect occupants during a fire. This includes everything from escape routes and compartmentation through to smoke control and firefighting access.
You will often see BS 9991 used alongside Approved Document B, particularly on taller or more complex residential projects where a more detailed fire strategy is required.
What Does BS 9991 Cover?
Unlike product standards that focus on individual components, BS 9991 looks at how the building performs as a whole during a fire.
The guidance covers areas such as:
- Escape routes and stairwells
- Corridor and lobby design
- Fire separation between flats
- Smoke ventilation systems
- Firefighter access
- Building layout and compartmentation
The overall aim is straightforward, helping ensure people can either evacuate safely or remain protected within their flat depending on the building’s fire strategy.
The Stay Put Strategy
A key part of BS 9991 is the stay put approach used in many apartment buildings.
This means a fire should remain contained within the affected flat long enough for other occupants to safely remain within their own apartments unless directly impacted.
For this strategy to work properly, several things need to perform together, including:
- Fire compartmentation
- Smoke control systems
- Protected escape routes
- Fire-resistant construction
Smoke ventilation therefore becomes an important part of the wider fire safety strategy, not just an isolated system within the building.
Key changes in BS 9991:2024
The 2024 update introduced some important changes, particularly around smoke control:
BS 9991 vs Approved Document B
BS 9991 and Approved Document B are closely linked, but they do slightly different jobs.
Approved Document B provides the main Building Regulations guidance used to meet fire safety requirements.
BS 9991 provides more detailed guidance specifically for residential buildings, often taking a more design led approach to areas such as smoke control, evacuation, and escape routes.
A simple way to think about it is:
- Approved Document B sets the baseline fire safety guidance
- BS 9991 develops that guidance further for residential buildings
On many modern residential projects, particularly taller buildings, BS 9991 is now playing a much bigger role in shaping the overall fire strategy.
Why BS 9991 Matters More Today
Following the Grenfell Tower fire and wider changes to UK building safety legislation, residential fire safety is under far greater scrutiny than ever before.
This means smoke ventilation systems are now playing a much larger role within residential building design, particularly on higher-risk developments.
Early coordination between architects, fire engineers, smoke ventilation specialists, and contractors has become increasingly important to ensure systems are not only compliant, but genuinely suitable for the building and fire strategy involved.
There’s a lot of guidance to work through, and it is not always clear what is needed for your building.
At Rocburn, we review your drawings or fire strategy and help you work out the right approach.
Our smoke ventilation specialists work to the standards to ensure compliance. If you need any help, contact us and we will be happy to help!
