Fire Strategies for High-Rise Residential Buildings

Why High-Rise Residential Buildings Require Specialist Fire Strategies

High-rise residential buildings — those over 18 metres in height, equivalent to approximately six storeys — present fire safety challenges that are fundamentally different from those of lower-rise buildings. Greater height means longer evacuation times, greater dependence on firefighting lifts and rising mains, more complex smoke control requirements, and a higher consequence of any failure in the fire safety strategy. The Building Safety Act 2022 recognises this by classifying buildings over 18 metres with at least two residential units as higher-risk buildings, subject to the most stringent regulatory requirements in the UK building safety framework.

Applicable Standards for High-Rise Residential Fire Strategies

The primary standard for residential fire strategies in the UK is BS 9991:2015 — Fire Safety in the Design, Management and Use of Residential Buildings. For buildings over 18 metres, BS 9991 sets more stringent requirements than Approved Document B in several key areas:

• Fire resistance — compartment walls and floors in buildings over 18 metres typically require 60-minute fire resistance rather than the 30-minute standard applicable to lower buildings
• Sprinkler systems — BS 9991 requires sprinkler systems in all new residential buildings over 11 metres in height in England (and at a lower threshold in Wales and Scotland)
• Staircase configuration — for buildings over 18 metres with floor areas above certain thresholds, two staircases are typically required
• Firefighting facilities — buildings over 18 metres require firefighting shafts (comprising a firefighting staircase, firefighting lobby, and firefighting lift), rising mains at specified intervals, and firefighting access routes
• External wall construction — buildings over 18 metres must comply with regulation 7(2), which limits the use of combustible materials in external wall construction

Evacuation Strategy

The standard evacuation strategy for purpose-built blocks of flats in the UK is stay put — residents in flats not directly affected by a fire remain in their homes while the fire and rescue service responds and extinguishes the fire. Stay put relies entirely on the integrity of the building's fire compartmentation and the effectiveness of the means of escape for those in the flat of origin.

For buildings over 18 metres, the stay-put strategy must be supported by robust compartmentation — 60-minute fire resistance, maintained self-closing fire doors throughout, and no combustible external cladding that could allow fire to bypass internal compartmentation. Where these conditions cannot be guaranteed, a different evacuation strategy — such as simultaneous evacuation or evacuation alert systems — may be required.

Fire Strategy Requirements at Gateway 2

For new high-rise residential buildings, the Building Safety Act 2022 gateway process requires a comprehensive fire strategy to be submitted to the Building Safety Regulator at Gateway 2. The BSR scrutinises high-rise residential fire strategies more rigorously than any other building type, given the higher consequences of failure. The fire strategy must address all elements of the building's fire safety design in sufficient detail for the BSR to assess compliance — a high-level strategy document will not pass Gateway 2.

Retrofit and Existing Buildings

For existing high-rise residential buildings, the requirements of the Building Safety Act 2022 mean that all buildings over 18 metres must now be registered with the BSR and must have a building safety case. Where no original fire strategy exists — common for buildings constructed before modern fire safety standards were developed — a retrospective fire strategy must be produced. This is one of the most important services provided by Fire Safety Services for the existing high-rise residential sector.