High-Rise Residential Fire Strategies — An Overview

High-rise residential buildings — defined under the Building Safety Act 2022 as those over 18 metres or 7 storeys containing at least two residential units — require a more detailed and carefully considered fire strategy than lower-rise residential buildings. The combination of greater building height, large numbers of occupants, and the complexity of vertical means of escape creates fire engineering challenges that require bespoke solutions.

The Applicable Standards

For high-rise residential buildings, the primary standard is BS 9991:2015 (Fire safety in the design, management and use of residential buildings — Code of practice). BS 9991 provides specific guidance for residential buildings and deals with issues that Approved Document B does not address in sufficient detail for high-rise applications, including:

• Means of escape for residents who cannot self-evacuate
• Evacuation strategy — simultaneous evacuation vs stay-put
• Firefighting facilities — firefighting shafts, dry and wet rising mains, firefighting lifts
• External wall fire safety
• Balcony design and fire spread

The Building Safety Act Requirements

For buildings over 18 metres, the Building Safety Act 2022 adds three layers of regulatory requirement on top of the standard building control process. Gateway 1 requires a fire statement at planning stage. Gateway 2 requires BSR approval of the design before construction begins. Gateway 3 requires BSR sign-off at completion. The fire strategy — produced by a chartered fire engineer — is the central document at each of these stages.

Evacuation Strategy for High-Rise Residential Buildings

The evacuation strategy for high-rise residential buildings is one of the most consequential fire engineering decisions. Post-Grenfell, the default stay-put strategy has come under intense scrutiny and the Building Safety Regulator expects a carefully considered and justified evacuation strategy in Gateway 2 submissions. For new high-rise buildings, the trend is towards enhanced evacuation strategies — either simultaneous evacuation supported by a simultaneous evacuation management system, or a phased evacuation approach.

External Wall Fire Safety for High-Rise Buildings

The Grenfell Tower fire demonstrated catastrophically what can happen when a high-rise residential building's external wall is combustible. For new high-rise residential buildings, the Building Regulations now require that the external wall must achieve European Classification A1 or A2 — effectively non-combustible construction throughout. This constraint significantly affects facade design and specification, and the fire strategy must address external wall fire safety explicitly.