Building Regulation Part B: Your Simple Guide to Fire Safety Compliance

Building Regulation Part B: Your Simple Guide to Fire Safety Compliance

Thinking about starting a building project? Whether it’s a small home extension or a brand-new development, there’s one part of the Building Regulations you simply can’t ignore: Part B.

Covering everything related to fire safety, Part B is essential for keeping your design compliant and your building safe. Getting it right isn’t just about ticking boxes; it’s what ensures your project gets approved and can be safely used once the work is done.

What Is Approved Document B (Fire Safety)?

Building Regulation Part B, officially known as Approved Document B, is the UK’s core guidance for fire safety in and around buildings. It ensures every structure is designed to:

• Keep occupants safe
• Limit the spread of fire to neighbouring properties
• Allow firefighters to access and manage fires effectively

Approved Document B is split into two volumes:

• Volume 1: For dwellings (houses, flats, apartments)
• Volume 2: For non-dwellings (commercial buildings, hospitals, care homes, and schools)

Ultimately, Part B ensures that your building has safe escape routes, uses materials that control fire spread, and allows the fire service to access the site effectively. Getting these details right on your Building Regulations Drawings is non-negotiable.

The Four Key Areas of Part B Compliance

Part B is divided into four main areas that your architectural drawings must address. Each one is vital for Building Control approval.

1. Means of Warning and Escape

This section focuses on getting people out safely. It includes:

• Early warning systems such as smoke alarms and heat detectors
• Safe, accessible escape routes to a place of ultimate safety

For example, a new bedroom in a loft conversion must include an escape window that meets the minimum size requirements. You can see how this applies in practice on our Loft Conversion Drawings page.

2. Internal Fire Spread (Linings and Structure)

This requirement serves two main purposes:

• Linings: Internal surfaces like walls and ceilings must be made from materials that resist rapid fire spread.
• Structure: The main structure (including beams and supports) must remain stable for a set period, allowing occupants time to escape.

You may need guidance from a qualified Structural Engineer to ensure adequate fire resistance for steelwork or structural elements.

3. External Fire Spread

External fire spread focuses on protecting neighbouring properties. It requires design measures that prevent fire from spreading across external walls or roofs and onto nearby buildings.

This can affect your choice of materials, especially if your extension or new build is close to a property boundary. For more details on how material selection is handled during design, explore our Working Drawings service.

4. Access and Facilities for the Fire and Rescue Service

Your design must allow firefighters safe and adequate access to the site and provide the necessary facilities to tackle fires effectively.

This includes considerations such as:

• Driveway and access routes for emergency vehicles
• Access to water supplies
• Fire-fighting shafts or stairs in larger buildings

How to Achieve Building Control Compliance

While Approved Document B is the standard route to compliance, it’s not the only one.

For simpler residential projects such as single-storey extensions or loft conversions, your architect or Building Control Officer can guide you through specific requirements. These are often illustrated in your technical drawings, showing:

• Door fire-rating levels
• Smoke alarm locations
• Escape window sizes and routes

For larger or more complex buildings (such as care homes or multi-storey developments), you may need a fire-engineered solution. This involves a fire safety specialist designing a tailored strategy to meet the functional requirements of Part B, often providing more flexibility than following the Approved Document alone.

Whether you’re building a home extension or developing commercial premises, fire safety should never be an afterthought. Including these measures from the start will save you time, money, and potential redesigns later.

Need Help with Part B Compliance?

Our team at Online Drawing UK prepares professional Building Regulations Drawings that meet Part B fire safety standards. We work with clients across the UK to ensure every design complies with both planning and Building Control requirements.

If you have an extension or conversion idea you’d like to check against the fire safety regulations, get a call back or contact us today to discuss your project.