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Building Regulations Part B


Reading time: 8 minutes


What is Approved Document B, or Building Regulations fire safety legislation?

Building Regulations Part B covers fire safety and is split into two separate documents: Building Regulations: Fire Volume 1, which applies to dwellings (residential properties including new homes, extensions and renovations), and Building Regulations: Fire Volume 2, which applies to non-dwellings (non-residential properties such as offices, shops or structures which have no living facilities such as garages).


These latest documents incorporate both the 2020 and 2022 updates. Both volumes include information about the materials which must be used in order to meet fire Building Regulations Part B, as well as solutions and important ways to comply when working on a project. The documents both cover the same subjects but detail different ways to ensure the safety of those inside the different types of building, as well as the safety of firefighters and nearby occupants in case of fire. Both volumes consider escape routes, ways to stop fire spreading, fire and smoke detection systems and fire-safe structural requirements. The Approved Documents do change periodically, so this article covers the most recent 2022 changes.


Each document is split into six sections:

  • B1: Means of warning and escape

  • B2: Internal fire spread (linings)

  • B3: Internal fire spread (structure)

  • B4: External fire spread

  • B5: Access and facilities for the fire service 

  • 6(3), 7(2) and 38: Additional fire safety information


What are the changes to Building Regulations Part B?

The new updates to Building Regulations fire safety requirements in Approved Document B took effect on 1st December 2022. The most important updates are covered in both Volume 1 and Volume 2 and feature:

  • A ban on combustible materials used inside and outside of building walls (such as cladding)

  • Secure information boxes in blocks of flats or apartments over 11m in height

  • Evacuation alert systems for flats over 18m in height


The above changes are in addition to the 2020 updates as outlined below:

  • Sprinklers in blocks of flats require a lower trigger height of 11m (previously 30m)

  • Appropriate safety signage to assist the fire service with floor and flat identification numbers in buildings over 11m in height


How do I meet the Part B Building Regulations fire safety requirements?

The building’s design and construction must comply with the health and safety measures for building users, set out in the technical requirements, as well as using the building materials and workmanship detailed in Building Regulations Part B. Work must comply by law to prevent internal and external fire spread, offer the appropriate fire detection and alarm systems, consider means of escape, use non-combustible materials (inside, outside and on the roof), and plan vehicle access, firefighter access, venting and fire safety information. Remember that you will not have to cover both volumes of fire Building Regulations Part B, but either Volume 1 OR Volume 2 building fire safety regulations will apply to your project, depending on whether it’s a dwelling or not.

All about cladding and fire building regulations

It remains a hot topic in the news and the 2022 updates to Building Regulation Part B seeks to answer cladding and building fire regulations questions by stating that all materials must be non-combustible. Many combustible materials (such as the metal composite material with an unmodified polyethylene core material used at Grenfell Tower) is completely banned, no matter what the building’s height or use is. The Building Safety Act 2022 states where some existing buildings must be brought up to the new building fire regulations safety standards, and is particularly relevant to blocks of flats or multi-level housing. All external cladding has to meet the minimum standards of BS 8414: Fire performance of external cladding systems and test methods for non-loadbearing external cladding systems. The fire-resistant class for a building’s cladding and cavity materials depends on its use, size and position amongst other properties, which is shown in each of the Part B documents. 


Does building fire regulations Part B apply to extensions and refurbishments?

Building Regulations approval is needed for new construction work or when renovating a property; including extensions, new cladding and some other alterations to dwellings (Volume 1) and non dwellings (Volume 2). A building which was built before the fire building regulations was brought in doesn’t always have to be brought up to the code (except for unsafe external cladding - see above), but if work includes the new windows, loft conversions or extending then the regulations must be followed. Part B building regs states that, when not following the guidance for whatever reason, the builder must consult with the fire and rescue service and the building control body as soon as possible. You can find more information on all updated Building Regulations on our dedicated Travis Perkins Building Regs hub. You can apply for Building Regs approval here.


Disclaimer: Information displayed in this article is correct at the time of publication, but note that legislation changes periodically. Please refer to the latest publication of each approved article. The information contained on this page is intended as an overall introduction and is not intended as advice from a professional building control officer. The definition of ‘building work’ and when Building Regs approval is required is set out here. Travis Perkins aims to avoid, but accepts no liability, in the case that any information stated is out of date. Always consult the approved local authority building control team when considering any exemptions, and before undertaking any work.