Smoke Seals

Why Are Smoke Seals Important?

Smoke can move through very small gaps around doors, presenting a significant threat before thermal expansion seals the frame. Smoke inhalation is one of the most critical hazards in any fire incident, making robust smoke control a vital aspect of building safety.

Smoke seals help limit the movement of smoke through the perimeter gap around a door. This can support protected escape routes and reduce smoke spread between rooms, corridors and compartments during a fire. Consequently, they are frequently specified as critical components of fire door and smoke door assemblies to maintain the integrity of a passive fire protection strategy. Correct selection and installation are essential to ensure the door performs as intended during an emergency.

Smoke Seals vs Intumescent Strips

Smoke seals and intumescent strips perform different but related functions. A smoke seal helps block smoke movement around a door perimeter, while an intumescent strip expands when exposed to heat to help seal the gap between the door and frame. Combined fire and smoke seals provide both functions in one product where required by the door specification.

Depending on the building design and local requirements, some assemblies require fire-only protection, while others mandate combined fire and smoke resistance. Contractors and specifiers must review the door’s test evidence to determine whether to install individual intumescent strips or combined fire and smoke seals.

Types of Smoke Seals

Brush Smoke Seals

Brush seals use flexible bristles to help close the perimeter gap around a door. They are commonly used where a flexible seal is needed around uneven gaps or frequently used doors.

Fin Smoke Seals

Fin seals use a flexible rubber or silicone blade to press against the door or frame. They can provide a neat, close-fitting seal and are often used where a tighter contact seal is required.

Acoustic Smoke Seals

Acoustic smoke seals are designed to help reduce sound transmission as well as restrict smoke movement. They can be useful for offices, schools, healthcare settings, apartments and other buildings where both smoke control and sound reduction are important. For further technical guidance, read our article on how to soundproof a door.

Rebated Smoke Seals

Rebated smoke seals are fitted into a routed groove in the door or frame. This creates a cleaner finish and is often used on new fire door installations or door sets prepared for this type of seal.

Surface-Mounted Smoke Seals

Surface-mounted smoke seals are fixed directly to the door or frame face. They can be useful for retrofit projects, refurbishments or situations where routing a groove is not practical.

How to Choose the Right Smoke Seal

Choosing the right smoke seal depends on the door specification, gap size, fitting method and required performance. For fire doors and smoke protection doors, check whether the project calls for a smoke-only seal, a fire-only intumescent strip, or a combined fire and smoke seal.

Key selection factors to consider include:

• Door type and material: Timber, steel, or composite structures.
• Perimeter gap size: Matching seal depth to the physical clearances.
• Protection requirements: Determining if fire-only, smoke-only, or combined fire and smoke protection is needed.
• Installation style: Choosing between rebated or surface-mounted profiles.
• Seal profile: Evaluating brush, fin, or acoustic variants.
• Dimensions: Specifying appropriate product width, height, and length.
• Aesthetics: Matching colour and finish to the building’s interior design.
• Ratings and approvals: Selecting compatible FD30 smoke seals or FD60 smoke seals and verifying Certifire approval where relevant.
• Project type: Whether the seal is for a new installation, replacement, or retrofit project.

Where Are Smoke Seals Fitted?

Smoke seals are usually fitted around the perimeter of the door, either in the door edge, frame rebate or threshold area. Rebated smoke seals sit within a routed groove, while surface-mounted seals are fixed to the face of the door or frame, making them useful for many refurbishment projects.

Depending on the product, seals may feature self-adhesive backings for fast positioning, though some designs may require mechanical pins or specialist adhesives. Correct fitting is critical to maintaining the assembly's target leakage rate. For a deeper breakdown of physical placement, consult our informational guide on what is a smoke seal.

Smoke Seals, Fire Doors and Compliance

Smoke seals are commonly specified as part of fire door and smoke control strategies. When selecting products, check the door specification, certification and project requirements. Relevant references may include Approved Document B for fire safety guidance and BS EN 1634-3 for smoke leakage testing of door and shutter assemblies.

Ensuring your installations adhere to these guidelines helps maintain safety and supports compliance with UK building regulations. When selecting materials, always consult the individual door test evidence or seek competent fire safety advice.

Certifire-Approved Smoke Seals

Where shown, Certifire approval provides third-party assurance that a product has been independently assessed for its stated fire performance. This scheme is recognised globally by regulatory authorities, manufacturers, and installers as a mark of safety and quality consistency.

Using Certifire-approved items helps risk assessors, building managers, and specifiers document compliance. Please review individual product datasheets to confirm specific certification details and suitability for your designated door set.

Related Passive Fire Protection Products

Smoke seals are often specified alongside other passive fire protection and fire door products. Depending on the door assembly, users may also need:

• intumescent strips to prevent flame spread under high temperatures.
• All-in-one smoke seal fire door kits for straightforward installations.
• acoustic smoke seals and specialised drop-down door seals to treat threshold gaps.
• Overhead fire door closers to ensure doors return securely to their frames.
• Certified fire door hardware including hinges, locks, and latches.

For more detailed guides and advice, you can visit our fire safety advice centre.

Frequently Asked Questions