Approved Document B is the government’s official guidance on meeting the fire safety rules in the Building Regulations for England. It covers how buildings should warn people of a fire and let them escape. It also covers how to limit fire spread inside and outside the building, and how firefighters get in.

It is one of the most widely quoted documents in UK construction. However, it is also one of the most misunderstood. For a start, it is guidance rather than law. It also applies to building work, not to every existing building. On top of that, it is in the middle of a run of major changes.

In this guide we explain what Approved Document B is and where it stands in law. We also cover when it applies, what it says about fire doors, and the changes that have recently arrived or are on the way.

What Approved Document B Is

The Building Regulations 2010 set out the legal rules for building work in Schedule 1. Part B of that schedule deals with fire safety and contains five requirements:

• 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

The requirements themselves are short, and they describe outcomes rather than methods. For example, B1 asks for early warning of fire and escape routes that people can use safely. However, it does not say how to achieve that.

That is where Approved Document B comes in. It gives practical, detailed ways to meet each requirement for common building types. For instance, it covers escape route layouts, travel distances, fire resistance times, compartment sizes, cavity barriers, fire doors and much more.

It also comes in two volumes. Volume 1 covers homes, including houses and blocks of flats. Volume 2, by contrast, covers all other buildings, such as offices, shops, schools, hotels and industrial premises.

Where It Stands in Law

Approved Document B is statutory guidance rather than law, so you do not have to follow it.

Instead, it gives you a recognised route to compliance. Under the Building Act 1984, following an approved document tends to show you have met the requirement. On the other hand, departing from it tends to suggest you have not. A designer can still meet Part B another way, usually through a fire engineered design or a British Standard such as BS 9991 for homes or BS 9999 for other buildings. In that case, though, they then have to show the alternative is just as safe.

In practice, most straightforward building work follows Approved Document B. Building control bodies also use it as their benchmark.

Note that it only applies in England. Wales has its own version, which differs in places, while Scotland and Northern Ireland use separate systems entirely.

When Approved Document B Applies

This point causes the most confusion.

Approved Document B applies to building work. That means new buildings, extensions, major alterations, loft conversions and changes of use, such as turning a house into flats or an office into homes. You apply it when you design, approve and build the work.

However, it does not work backwards. A building that met an older edition does not suddenly fail when the guidance changes. Once people use a building, the Regulatory Reform (Fire Safety) Order 2005 mainly governs its fire safety, through the fire risk assessment and the duty to maintain fire safety measures.

Still, the two overlap in practice. A fire risk assessor will often use Approved Document B as a yardstick when judging whether an existing building is good enough. In addition, any changes you make to an existing building have to meet the Building Regulations in force at the time.

For higher-risk buildings, the Building Safety Regulator handles building control instead of local authority or private building control. Broadly, that means residential buildings of at least 18 metres or seven storeys with at least two homes.

[Image: a newly installed fire door on a protected corridor in a recently completed building] Alt text: A newly installed fire door on a protected corridor in a recently completed residential building built to Approved Document B.

What Approved Document B Says About Fire Doors

Fire doors run right through Approved Document B, because escape routes and compartments depend on them. Most of the detail sits in Appendix C. There, a table sets out the minimum fire resistance and smoke control for each door position.

For example, these are some of the positions people come across most often:

• Flat entrance doors, which normally need 30 minutes’ fire resistance with smoke control (E30Sa, broadly the same as FD30S)
• Doors onto protected stairs, corridors and lobbies
• The door between an integral garage and a house
• Doors to protected stairs in houses with a floor more than 4.5 metres above ground, including many loft conversions
• Doors in compartment walls, which generally need to match the wall they sit in
• Doors to protected shafts, plant rooms and higher-risk areas in other buildings

The guidance also covers self-closers, hold-open devices that release when the alarm sounds, signs, which way doors open on escape routes, and the hardware you can use.

Approved Document B gives the minimum rating for each position. Even so, the door itself then has to be a certified doorset with test evidence for that rating, and someone has to fit it to that evidence. Our guide to choosing the right fire door for your building explains how ratings match positions. Similarly, our guide to FD30 and FD60 specifications covers the two most common ratings. For flats in particular, see our guide on whether a flat entrance door needs to be a fire door.

Recent and Upcoming Changes

The government is currently updating Approved Document B in stages. So if you specify or fit fire doors, the dates matter.

The current base document is the 2019 edition, which includes the 2020 and 2022 changes. On top of that, three sets of changes apply:

2 March 2025. Changes came into force that removed the national BS 476 ratings for reaction to fire and roofs. As a result, the European BS EN 13501 ratings became the only route for those. The same changes also added guidance on sprinklers in new care homes.

30 September 2026. Changes came into force that require a second staircase in new residential buildings with a floor 18 metres or more above ground. They also added guidance on evacuation lifts and changed some fire door rules. Transitional rules apply here too. Broadly, projects that applied for building control before that date carry on under the old guidance, as long as work moves far enough along within 18 months.

2 September 2029. This change will remove the remaining BS 476 references for fire resistance, and it directly affects fire doors. Doors tested under BS 476-22 carry FD ratings such as FD30 and FD60. After the change, however, new projects under the guidance will use European ratings such as E30 and E60, based on testing to BS EN 1634-1. Existing doors do not stop complying on that date. Even so, makers, specifiers and fitters will need European test evidence for new work.

Alongside the Building Regulations guidance, BSI published the new code of practice for fire doors, BS 8214:2026, in March 2026. It replaces the 2016 edition and now also covers metal and composite fire doors.

What This Means for Building Owners

If you are planning building work, your designer and building control body will work to the edition of Approved Document B that applies to your project. So check which edition that is, especially if your project runs across one of the dates above.

If you manage an existing building, on the other hand, Approved Document B tells you how designers should have planned the building at the time. It is also a useful guide to what good looks like. However, your day-to-day duties come from the Fire Safety Order. The fire doors in your building need the right rating for their position, valid certification, correct fitting and regular maintenance. A fire door survey will tell you whether they meet that standard. After that, remedial works can fix many problems without a full replacement.

Compartments matter just as much. A fire door in a wall full of unsealed pipe and cable holes protects very little. For this reason, fire stopping and compartmentation work is the natural partner to any fire door programme.

Frequently Asked Questions

Is Approved Document B a legal requirement?

No. The legal requirements sit in Part B of Schedule 1 to the Building Regulations 2010, while Approved Document B is statutory guidance on how to meet them. Following it is the most common route to compliance. However, you can take another approach if it achieves the same level of safety.

Does Approved Document B apply to existing buildings?

It applies to building work, including alterations and changes of use. However, it does not work backwards, so an existing building does not have to meet the latest edition. Instead, the Fire Safety Order governs fire safety in existing buildings.

What is the difference between Volume 1 and Volume 2?

Volume 1 covers homes, including houses and blocks of flats. Volume 2, by contrast, covers all other buildings, such as offices, shops, schools, hotels and industrial premises.

What does Approved Document B say about fire doors?

It sets the minimum fire resistance and smoke control for doors in each position, mainly in Appendix C. It also covers self-closers, hold-open devices, signs and hardware. For example, flat entrance doors normally need 30 minutes’ fire resistance with smoke control.

Will FD30 and FD60 ratings disappear?

For new work under the guidance, yes. The BS 476 fire resistance references go on 2 September 2029, and after that new projects will use European ratings such as E30 and E60. However, existing doors with valid BS 476 evidence still comply after that date.

Need Fire Doors That Meet the Guidance?

At CFP Carpentry & Fire Prevention, we supply and install certified fire doors for new build, refurbishment and change-of-use projects. That includes bespoke fire doors for odd-sized openings and metal fire doors for plant rooms and service areas. We also survey and repair fire doors in buildings already in use.

We cover:

• South & South West: Bournemouth, Southampton, Poole, Exeter, Plymouth
• London & South East: London, Reading, Guildford, Slough, Croydon
• Midlands & Wider Reach: Bristol, Swindon, Oxford

Working on a project and not sure which doors your building needs? Get in touch to discuss your fire door installation.