The Linear Seal
When it comes to fire safety, attention to detail is paramount. While fire door assemblies can offer suitable protection, it's equally crucial to consider fire stopping at the interface between the frame's back and the wall. Fire stopping entails sealing openings and penetrations in walls, floors, and ceilings to halt the spread of fire, smoke, and toxic gases. Addressing this aspect at the linear gap seal further strengthens the efficacy of the fire door assembly.
Linear Seal in Fire Door Assemblies and BS 8214: 2016 Compliance
Linear Seal Definition:
The protected gap between the back of the frame and the opening where the fire door assembly is fixed is known as the linear seal.
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Fire Door Inspections:
Fire door inspectors often rely on non-intrusive inspections, studying photographic and documentary evidence for the linear seal's precise specification. If an intrusive inspection is deemed necessary, it involves removal and refitting of architraves, requiring a joinery contractor with suitable insurance.
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Regulation 38 Compliance:
Door assemblies fitted in accordance with Regulation 38 should have comprehensive information, including details of the linear seal with photos before, during, and after installation, demonstrating compliance with BS 8214: 2016.
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BS 8214: 2016 - Timber-based Fire Door Assemblies:
Provides guidance for the specification, installation, and maintenance of timber-based fire doors with up to 2 hours of fire resistance.
Section 9.4.1 specifically addresses the linear seal, recommending standard solutions for sealing joints between the frame and structure.
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Recommended Sealant Testing:
Mastics and expanding foam sealants should be approved for use as a linear gap seal, tested according to BS 476-20 or BS EN 1366-4.
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BS EN 1366-4 assesses a product's capacity to seal a gap during a fire test, simulating flashover conditions with temperatures exceeding 500°C within the first minute.
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Sealant Use Conditions:
Use of sealants is conditional on having test evidence for the specific structure being used. Restrictions apply unless appropriate test evidence is available.
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Alternative Testing:
Mastics and foams can alternatively be used if included in a fire resistance test on a door assembly according to BS 476-22 or BS EN 1634-1.
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Compliance with BS 8214: 2016 is crucial for fire door assemblies, especially concerning the linear seal. Properly tested and approved sealants contribute to the fire resistance of door assemblies, ensuring they meet stringent safety standards. The documentation of linear seals during and after installation is vital for demonstrating compliance with regulations and standards.