Fire Escape Routes in Residential Buildings

What This Requirement Covers

Approved Document B1 requires that adequate means of escape from fire are provided in all dwellings. The purpose is to ensure that occupants can safely reach a place of safety outside the building in the event of fire, without being overcome by smoke or heat.

The requirements differ significantly between houses and flats, and depend on the number of storeys, floor area, and whether the dwelling has an open-plan layout.

Key Requirements

Houses Up to Two Storeys

1. Every habitable room should either open directly onto a hallway or stair leading to the final exit, or have an openable window or door for emergency egress
2. Emergency egress windows must have an unobstructed openable area of at least 0.33 m² with minimum dimensions of 450 mm high and 450 mm wide
3. The bottom of the openable area must be no more than 1100 mm above the floor
4. First-floor rooms served only through another room (inner rooms) are acceptable provided the outer room has a suitable detection system

Houses of Three or More Storeys

1. A protected stairway is required, enclosed with fire-resisting construction (minimum 30 minutes fire resistance)
2. All habitable rooms on upper floors should open directly onto the protected stairway or have emergency egress windows
3. The protected stairway must lead to a final exit or give access at ground level to a final exit
4. Alternative escape routes may be needed where the travel distance from any point in a storey exceeds 9 metres to the stair
5. Automatic fire detection (Grade D1 LD3 minimum) is required throughout

Flats

1. Each flat should be separated from common areas by fire-resisting construction (minimum 30 minutes, or 60 minutes in buildings over 18 metres)
2. Flats above ground floor must have access to a protected common stairway
3. In single-stair buildings, the travel distance from any flat entrance to the stair should not exceed 7.5 metres
4. Buildings over 11 metres in height should have alternative escape routes or a fire-fighting lobby approach
5. Buildings over 18 metres in height require a minimum of two staircases, each accessed via a fire-fighting lobby

Open-Plan Layouts

Open-plan ground floors in houses are addressed in Approved Document B, Diagram 2.1:

1. Where the kitchen is open to the stairway, a fire detection and alarm system (LD1 or LD2) must be provided
2. The kitchen area should have a heat alarm
3. The plan distance from the cooking area to the nearest exit should not exceed 9 metres
4. Sprinkler protection may be required in some open-plan configurations

Exceptions and Exemptions

1. Basements with rooms opening directly to an external door at basement level do not require a protected stairway for that storey
2. Loft conversions in two-storey houses require a protected stairway from the new storey to the final exit; an alternative is a sprinkler system to BS 9251 combined with 30-minute fire doors
3. Where compliance with the standard provisions is not reasonably practicable (particularly in existing buildings), a fire-engineered solution may be accepted

Regional Variations

1. England: Approved Document B (2019 edition with 2020 amendments) applies
2. Wales: Approved Document B applies; sprinklers are mandatory in all new dwellings under the Domestic Fire Safety (Wales) Measure 2011
3. Scotland: Scottish Building Standards Section 2 (Fire) has different provisions, including mandatory sprinklers in flats and sheltered housing
4. Northern Ireland: Technical Booklet E applies with broadly similar provisions but separate guidance documents

Practical Compliance Tips

1. Measure travel distances along the actual route of travel (not straight-line distances)
2. Ensure fire doors to protected stairways are fitted with self-closing devices and appropriate cold smoke seals
3. Emergency egress windows must be accessible without keys or special tools
4. In loft conversions, do not underestimate the cost of extending the protected stairway down to the final exit
5. Consider early-stage sprinkler design as a trade-off to relax travel distance or open-plan restrictions
6. All glazing in fire-resisting walls must be fire-rated to the appropriate standard
7. Submit escape route drawings to Building Control early in the design process to avoid costly redesigns