Smoke control.

Approved Document B ‘Fire safety’ recognises, in Table B1 to Appendix B, certain door positions where restriction of smoke leakage at ambient temperatures is needed (except where specific pressurisation techniques are used). These doors should have a leakage rate not exceeding 3m³/m/hour, from head and jambs only, when tested at 25 Pa pressure under BS 476: Section 31.1. or BS EN 1634-3 (classification Sa).

Smoke Testing

BS 476 : Part 31, Section 31.1 : 1983 ‘Method of measuring smoke penetration through doorsets and shutter assemblies’ and BS EN 1634-3:2004 ‘Smoke control test for door and shutter assemblies’ allows smoke leakage at various pressure differentials to be measured.

Practical Considerations 

Seals fitted to door edges to meet cold smoke conditions required by Part B are generally stop-mounted or edge-mounted flexible neoprene blade types which require close tolerances.

Edge-mounted seals can bind if not accurately fitted, negating smoke resistance. Our certification relates to blades: brush type seals have not been tested for smoke leakage within our products and are not recommended. Double action doors are particularly difficult to seal due to the nature of the ironmongery required, larger gaps are encountered at the foot of the door. Consequently Leaderflush Shapland do not offer certification for double action smoke control doorsets. Some guides stress the importance of sealing the junction of frame with partition for smoke containment. BS 8214 offers guidance on the maintenance of seals to ensure continued performance.

BS 476 Part 31.1, HTM58 Part B, considers smoke leakage at door head and jambs only. In contrast, BS 9999 and BS 8214 require that rated doors should have no more than a 3mm gap at the bottom, which can be difficult to achieve with some floor finishes. Alternatively, these can be sealed with threshold seals or drop-seals. Local Building Control Officer advice should be sought on this issue.

Leaderflush Shapland solutions for fire and smoke control

Maximum fire ratings for various product ranges to suit particular applications are shown below. Appropriate smoke seals and intumescents are automatically included by us to meet the specific performance requirements of each doorset. For vision panels, refer to Part N (Glazing safety)