Fire Doors: A Complete Guide

In certain situations in the UK such as in some rented properties, some commercial establishments and the likes it is the law to install a fire door between certain rooms.

In this DIY guide we look at the humble fire door and discover what the rules and regulations are, what different types there are and also how to fit one.

What is a Fire Door?

A fire door is a specially designed door that helps stop the spread of fire and smoke within a building. It is built using fire-resistant materials and is tested to hold back flames for a set period, usually 30 or 60 minutes (known as FD30 or FD60). This delay gives people more time to escape safely and helps limit damage to property.

In UK homes and commercial buildings, fire doors are a key part of fire safety. They are commonly fitted between areas such as kitchens, garages and escape routes like hallways and staircases.

When installed correctly, a fire door forms a sealed barrier that slows down heat and smoke, which are often more dangerous than flames.

A complete fire door system includes more than just the door itself. It must be fitted with the correct frame, hinges, intumescent strips (which expand when heated) and fire-rated seals. All components must meet UK safety standards to ensure the door performs properly in the event of a fire.

For best results, fire doors should always be installed and maintained correctly. Gaps, poor fitting or damaged seals can reduce their effectiveness. Regular checks help ensure your fire door continues to protect your home or building as intended.

Why are There Rules for Fire Doors?

Fire door rules exist to slow the spread of fire and smoke, helping protect people and property. Fires can start in any room, so these regulations are designed to contain the fire in one area for as long as possible.

In most UK homes, fire doors are rated to hold back fire for at least 30 minutes. This provides vital time for occupants to escape safely and for emergency services to respond.

• Step 1: Understand the Purpose – Fire doors create a barrier that limits the spread of flames, heat and smoke.
• Step 2: Allow safe escape time – A standard 30-minute rating (FD30) gives people enough time to exit the building safely.
• Step 3: Follow UK regulations – Fire door requirements are set out in Approved Document B of the Building Regulations, which covers fire safety in residential and commercial properties.
• Step 4: Ensure correct installation – To be effective, fire doors must be fitted properly with the correct components and maintained over time.

Following these rules is essential to ensure fire doors perform as intended in an emergency and comply with regulations.

What are the Regulations

Fire door rules in the UK are set out in Approved Document B of the Building Regulations. Part 1 covers fire safety in homes (dwelling houses) and explains where fire doors are required and how they should perform.

It’s important to understand that internal fire doors and fire exits are not the same. Internal fire doors slow the spread of fire between rooms, while fire exits provide a safe route out of the building.

• Step 1: Know the guidance – Approved Document B outlines fire safety requirements for domestic properties, including door ratings and placement.
• Step 2: Understand door types – Internal fire doors protect escape routes, while fire exit doors lead directly outside. Each has different rules.
• Step 3: Consider property layout – Regulations vary depending on the building. Homes with multiple floors, loft conversions or basements often need additional fire protection.
• Step 4: Follow the correct standards – Always check current Building Regulations before starting work to ensure full compliance and safety.

Understanding and following these regulations helps ensure your property is safe and legally compliant.

What is the Requirement?

A common mistake is thinking a fire door alone is enough. In reality, regulations require a complete fire door set, not just the door leaf.

A fire door set includes all parts working together: the door, frame or lining, hinges, seals, latch or lock and surrounding structure. Every component must be designed to resist fire for the same rated period.

• Step 1: Use a complete system – Install a full fire door set, not just a replacement door in an existing frame.
• Step 2: Fit compatible components – Hinges, locks, seals and stops must all be fire-rated and suitable for the door.
• Step 3: Prevent gaps and weak points – Poor fitting or gaps can allow smoke and flames through, reducing effectiveness.
• Step 4: Check certification – Use products that are Certifire approved and CE marked where required to meet UK standards.

For a fire door to perform correctly, every part must work together as one tested system.

What is Certfire

Certifire is an independent third-party certification scheme that verifies fire protection products meet strict safety and performance standards.

It tests and approves items such as fire doors, seals, hinges, and fixings to ensure they perform reliably in real fire conditions.

Products with Certifire approval are widely recognised in UK Building Regulations and across the construction industry as meeting trusted fire safety requirements.

Choosing certified components helps ensure your fire door system is compliant, effective and built to protect.

What is CE Marked?

CE marking (Conformité Européenne) shows that a product meets key European safety, health and performance standards.

For fire door installations, a CE mark confirms that the product has been tested and approved to comply with relevant European safety regulations.

Appendix B of Approved Document B: Fire Doors

The table below, taken from UK Building Regulations, shows the minimum fire resistance rating for fire doors. For example, an FD30 door is designed to resist fire for at least 30 minutes.

Wall and ceiling materials also affect how quickly fire spreads. While they are rarely the first to ignite, using suitable materials is essential. Standard 12.5mm plasterboard is widely used in homes and can provide up to 30 minutes of fire protection when correctly installed.

Fire Door Rules in Simplified Terms

Fire doors are a key part of home safety. In a fire, the complete door set, including the frame, hinges and locks, must resist fire and smoke for at least 30 minutes (FD30 standard).

In certain areas, such as loft conversions, basements, integral garages and multi-storey homes, a self-closing device is also required. This ensures the door shuts fully and the latch engages, helping to stop fire and smoke from spreading.

These rules commonly apply to new builds, approved conversions and properties used as houses in multiple occupation (HMOs).

Definition of Fire Door

A fire door is a complete door set designed to slow the spread of fire and smoke for a set period of time.

It includes the door, frame, hinges and locks, all working together to contain any fire and protect escape routes, giving occupants vital time to exit safely and for emergency services to respond.

Certfire Certificates and Door Labels

Fire doors come with a Certfire label that must not be removed, clearly identifying the door type for its intended use.

An FD30 door provides 30 minutes of fire resistance, while FD60 offers 60 minutes. Doors marked FRG30 or FRG60 include fire-resistant glazing for the same durations.

All fire doors must comply with British Standard 476 to ensure safety and reliability.

Fire Door Hinges

Fire doors must fit snugly in the frame, with a maximum gap of 5mm. They should be mounted on at least three metal hinges that can withstand temperatures of 800°C or higher to ensure full fire resistance.

Fire Door Closers

Before April 2007, all fire doors required self-closing devices that fully shut the door against the frame, overcoming any latch or lock resistance. Since then, this rule was relaxed, leaving installation as a homeowner’s choice for most doors.

However, door closers are mandatory for doors on floors above the second level and any door between the home and a garage.

Intumescent Strips and Smoke Control

Intumescent strips expand when heated, sealing gaps between the door and frame to prevent fire and smoke from spreading. Fire doors rated for 30+ minutes must have these strips fitted.

New doors should use 15mm strips, while existing frames can use 10mm strips. Many frames have pre-fitted intumescent strips, but stick-on versions are available for retrofitting.

Stick-on strips come in 5m packs (enough for one door) and are available in brown or white from most builders’ merchants and larger DIY stores.

Fire Door Locks and Latches

Fire doors require heat-resistant hardware, known as essential ironmongery. This includes door knobs, locks and latches with integral locking mechanisms, all of which must be CE marked.

Mortice and tubular latches must meet BS EN 12209 standards. Letterboxes can be fitted to fire doors, but the plate must also be CE marked, and the manufacturer’s instructions should confirm the door remains compliant with a letterbox installed.

Hanging a Fire Door

Fire doors are hung like standard doors but are heavier, solid timber units, so extra care is needed. Each door requires three strong hinges. For step-by-step guidance, see our hanging a door project.

Always keep fire doors closed. While door closers can seem inconvenient, they are essential for safety, helping prevent the spread of fire and smoke. Take care when installing to ensure the door functions correctly.

Fire doors provide a fantastic level of additional safety for any inhabitants of the building they are fitted in and if you are considering installing or even replacing doors in your home, should certainly be a consideration when choosing your new doors.