Approved Document B (Fire Safety) Volume 2: Buildings Other Than Dwellings – England Building Regulations
Official name: Approved Document B: Fire safety, Volume 2 – Buildings other than dwellings. This document is issued by HM Government (Ministry of Housing, Communities and Local Government) as statutory guidance to support the Building Regulations 2010 in England. It serves as the primary technical code for fire safety design in all building types except dwellings, encompassing offices, shops, commercial spaces, assembly halls, industrial units, and residential institutional buildings like hospitals and care homes.
The document is structured around five core functional requirements defined in Schedule 1: Requirement B1 (Means of warning and escape), Requirement B2 (Internal fire spread - linings), Requirement B3 (Internal fire spread - structure), Requirement B4 (External fire spread), and Requirement B5 (Access and facilities for the fire service). It also details compliance with Regulation 38 regarding the handover of fire safety information to building owners. This consolidated version includes the 2019 edition along with incorporated amendments from 2020, 2022, and 2025, and provides legal notice for forthcoming changes scheduled for September 2026 and September 2029.
Professional users including architects, fire engineers, and building control bodies utilize this volume to determine mandatory safety thresholds, such as maximum travel distances, minimum stair widths, and the classification of materials according to their reaction to fire and fire resistance.
Means of Warning and Escape (Requirement B1)
Requirement B1 focuses on ensuring buildings are designed with sufficient warning systems and safe egress routes to a place of safety outside the building.
- Horizontal Escape: Specifies travel distance limits based on Purpose Group. For example, a residential (institutional) building is limited to 9m in one direction and 18m where travel is possible in more than one direction (Table 2.1).
- Width of Escape Routes: Defines minimum widths for exits and escape routes based on the maximum number of people served. A route for up to 220 people requires a minimum width of 1050mm (Table 2.3).
- Single Escape Stairs: Allowed in specific situations, such as an office building with a maximum of five storeys above ground where the top storey floor level is no more than 11m (Section 3.3).
- Refuges: Mandates relatively safe waiting areas for people with reduced mobility on every storey of each protected stairway (Section 3.4).
Internal and External Fire Spread (Requirements B2, B3, and B4)
These requirements aim to inhibit fire growth over internal linings, prevent premature structural collapse, and restrict fire spread via cavities or external walls.
- Compartmentation: Requires non-residential buildings to be divided by compartment walls and compartment floors to contain fire. Size limits vary by height and use, such as a 2000m² storey area limit for unsprinklered shops (Table 8.1).
- Internal Linings: Classifies surface materials for walls and ceilings. Small rooms in residential accommodation require a minimum classification of D-s3, d2 (Table 6.1).
- External Walls: Details strict combustibility requirements. For relevant buildings with storeys over 18m, materials must achieve European Classification A2-s1, d0 or A1 (Section 12.15).
- Cavity Barriers: Mandated to close the edges of cavities and divide extensive concealed spaces, typically requiring 30 minutes of integrity and 15 minutes of insulation (Section 9).
Fire Service Access and Facilities (Requirement B5)
Provisions under Requirement B5 ensure that fire and rescue services can effectively access and operate within a building during an emergency.
- Vehicle Access: Sets perimeters for pump appliance access. Buildings over 24,000m² require access to 100% of the perimeter (Table 15.1).
- Firefighting Shafts: Required in buildings with a storey more than 18m above fire service vehicle access level. These shafts must contain a firefighting lift, a firefighting stair, and a firefighting lobby (Section 17.2).
- Fire Mains: Mandates dry fire mains for firefighting shafts and wet fire mains for buildings with a storey more than 50m high (Section 16.6).
- Basement Venting: Requires smoke outlets to be provided from every basement storey, with a cross-sectional area of at least 1/40 of the floor area (Section 18.6).
Significant Amendments and Transitional Provisions
The document outlines a phased transition to higher safety standards and the eventual removal of older British Standard classifications.
- 2020/2022 Sprinkler Changes: Reduced the trigger height for mandatory sprinklers in residential blocks of flats from 30m to 11m.
- 2025 Care Home Mandate: Introduces new provisions for mandatory sprinklers in care homes regardless of height.
- 2026 Stair Requirement: Effective 30 September 2026, blocks of flats with a storey 18m or more in height must be provided with more than one common stair.
- Removal of National Classes: National classifications for reaction to fire are removed in 2025, and those for fire resistance will be removed on 2 September 2029, making the European Classification (Euroclass) system the sole standard.
Frequently Asked Questions
What building types does Approved Document B Volume 2 cover?
It covers all building types other than dwellings, including offices, shops, commercial premises, assembly and recreation spaces, industrial buildings, and residential institutional buildings like care homes and hospitals.
At what height is a second common stair required in blocks of flats?
Per the 2026 amendments, more than one common stair must be provided in blocks of flats with a storey 18m or more in height.
What is the mandatory sprinkler trigger height for offices?
Buildings in the office purpose group require automatic sprinkler systems if they have a top storey more than 30m above ground level, as per Table B2 and Section 8.14.
When is a firefighting shaft containing a firefighting lift required?
A firefighting shaft with a lift is required if the building has a floor more than 18m above, or more than 10m below, fire service vehicle access level.
What is the maximum horizontal escape travel distance in an office?
In an office (Purpose Group 3), the limit is 18m where travel is possible in one direction only and 45m where travel is possible in more than one direction.
What are the fire resistance requirements for basement smoke outlet shafts?
Outlet ducts or shafts must be enclosed in construction achieving a Class A1 rating and have fire resistance at least equal to that of the element through which they pass.
Are sprinklers mandatory in care homes?
Yes, under the 2025 amendments, care homes must be fitted with a sprinkler system throughout the building in accordance with Appendix E.
What is Regulation 38 in the context of fire safety?
Regulation 38 requires that fire safety information is given to the 'responsible person' by the person carrying out the work, no later than the date of completion or occupation, to enable an effective fire risk assessment.
