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Aim & Objectives

Discuss the influence of the Building Regulations on fire safety.
Apply compliance principles from Approved Document B to realistic construction scenarios.

At the end of the lesson, the students should be able to:�

Achieving Compliance with the Building Regulations: Approved Document B (Fire Safety)

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Approved Document - Part B: Fire Safety

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Approved documents B provides practical guidance on how to meet Building Regulations fire safety requirements.

Divided into two volumes:

Volume 1: Dwellings (houses, flats)
Volume 2: Buildings other than dwellings (offices, schools, etc.)

Covers five core fire safety requirements (B1–B5): detection and warning, internal and external fire spread, means of escape, and firefighting access.

Approved Document - Part B: Fire Safety

Overview

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Approved Document - Part B: Fire Safety

Key Design Principles

Figure 1. Means of escape from dwelling houses (The Welsh Government, 2010).

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Approved Document - Part B: Fire Safety

Means of Escape (Requirement B1) [cont’d]:

For homes with top floors above 7.5 meters, a second escape staircase or additional protection such as sprinklers will be necessary to compensate for the increased fire risk.
For a loft conversion in a two-storey building, a protected route must be provided through a stairway that does not pass through any rooms. Existing first-floor ceilings should be adapted to achieve 30 minutes of fire resistance, and mains-powered, interlinked smoke alarms should be installed (Multi-turn, no date).

Key Design Principles

Figure 2. Fire separation in houses with more than one floor over 4.5m above ground level (The Welsh Government, 2010).

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Approved Document - Part B: Fire Safety

Fire Detection and Warning Systems:

Smoke and heat alarms must be installed in all new dwellings. Alarms should interlink so activation in one room triggers alerts in others.
All new residential and domestic premises shall be provided with automatic fire suppression.

Example: Grade D1 alarm system compliance with BS 5839-6 for new flats.

Key Design Principles

Figure 3. Placing of smoke and heat alarms (LABC, 2018).

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Approved Document - Part B: Fire Safety

Internal Fire Spread (Requirements B2–B3):

Use fire-resisting materials for floors, walls, and ceilings to inhibit fire and smoke spread.

Example: 30-minute minimum fire resistance between dwellings or between a house and its garage.

The REI marking identifies the fire-resistance rating of a structure. It means a building component can maintain its structural stability (R), prevent the passage of flames and smoke (E), and limit the transfer of heat (I) for a specified amount of time. For example, an REI 60 rating means the element will perform these functions for 60 minutes.
R = Load-bearing; E = Integrity; I = Thermal Insulation

Key Design Principles

Figure 4. Table A1. Specific provisions of test for fire resistance of elements of structure etc. (The Welsh Government, 2010).

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Approved Document - Part B: Fire Safety

External Fire Spread (Requirement B4):

The external walls of the building shall adequately resist the spread of fire over the walls and from one building to another.
The roof of the building shall adequately resist the spread of fire over the roof and from one building to another.
Limit the spread of flames on or between buildings by using non-combustible cladding and roofing materials.

Example: Ban on combustible materials on external walls of residential buildings over 11m in height.

Key Design Principles

Figure 4. Table A1 (cont’d). Specific provisions of test for fire resistance of elements of structure etc. (The Welsh Government, 2010).

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Approved Document - Part B: Fire Safety

Internal Fire Spread (Requirements B2–B3):

Use fire-resisting materials for floors, walls, and ceilings to inhibit fire and smoke spread.

Example: 30-minute minimum fire resistance between dwellings or between a house and its garage.

External Fire Spread (Requirement B4):

Limit the spread of flames on or between buildings by using non-combustible cladding and roofing materials.

Example: Ban on combustible materials on external walls of residential buildings over 11m in height.

Key Design Principles

Figure 4. Table A1 (cont’d). Specific provisions of test for fire resistance of elements of structure etc. (The Welsh Government, 2010).

Figure 5. Table A2. Minimum periods of fire resistance for dwellinghouses (The Welsh Government, 2010).

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FIRE PERFORMANCE TESTING OF MODULES AND PANELS

Full-scale fire tests simulate real fire exposure to assess fire resistance and spread.

In line with BS 476 and Building Regulations Part B standards.

https://www.youtube.com/watch?v=pZABBW8PEI4

The UK is withdrawing the British fire safety standard BS 476 in favour of the European standard BS EN 13501 to create a single, consistent system for material performance testing across Europe. The transition will be completed by September 2029, after which BS 476 will be obsolete for building regulations in England.

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Approved Document - Part B: Fire Safety

Firefighting Access (Requirement B5):

Provide safe access routes and adequate water supplies for firefighting operations.

Example: Fire appliances must be able to park within 18m of the building entrance.
A dry riser must be provided for every 900m^2 of floor at every level aside from ground level.
No part of any floor must be more than 60 metres from a dry riser outlet.

Key Design Principles

Figure 5. Dry risers (Fire and Security Group, 2021).