BS 7346: Components for Smoke and Heat Control Systems

BS 7346 is a multi-part British Standard covering components used in smoke and heat control systems. Where BS EN 12101 is a European harmonised standard family, BS 7346 is a British Standard that provides complementary guidance and component specifications - in some areas covering components that are not yet addressed by a published BS EN 12101 part.

Structure of BS 7346

BS 7346 is divided into eight parts. Three of the original specification parts have been withdrawn and superseded by BS EN 12101; the calculation and code-of-practice parts remain current:

How BS 7346 Relates to BS EN 12101

BS 7346 and BS EN 12101 address overlapping areas but serve different purposes:

• BS EN 12101 is a harmonised European standard - products certified to it can carry CE marking and be placed on the market across the European Economic Area. In the UK post-Brexit, UKCA marking applies, though CE marking continues to be accepted under current transitional arrangements.
• BS 7346 is a British Standard that predates the full BS EN 12101 series. Its three original specification parts have been withdrawn and superseded by BS EN 12101 parts. The calculation methods and codes of practice were not superseded and remain current, since BS EN 12101 does not provide the equivalent design methodology.

Superseded parts:

BS 7346-8 - Planning, Design, Installation, Commissioning and Maintenance

BS 7346-8:2013 is the code of practice most UK specifiers reference day to day. It sets out planning, design, installation, commissioning and maintenance practice for smoke and heat control systems built from BS EN 12101 components - bridging the gap between the product performance standards (BS EN 12101) and the building design standards (BS 9991 and BS 9999).

BS 7346-8 covers:

• System design methodology for smoke control
• Selection and sizing of components
• Integration of different system types (natural, mechanical, pressure differential)
• Commissioning requirements
• Maintenance guidance

BS 7346-7 - Covered Car Parks

BS 7346-7:2013 is the equivalent code of practice for smoke and heat control systems in covered car parks, giving functional recommendations and calculation methods specific to that building type rather than the general SHEVS methodology in Parts 4 and 5.

BS 7346-4 and -5 - Calculation Methods for SHEVS

BS 7346-4:2003 provides the calculation methodology for designing smoke and heat exhaust ventilation systems (SHEVS) using steady-state design fires - the manual calculation approach to determining required free area, reservoir depth, and ventilator sizing. BS 7346-5:2005 gives the equivalent methodology for time-dependent design fires. Both complement the performance-based approach in BS EN 12101-2 and the fire engineering approaches used in complex buildings.

For large, complex, or unusual buildings where the BS 7346-4/5 calculations may not be directly applicable, CFD (computational fluid dynamics) analysis is used - the SCA publishes guidance on the use of CFD for smoke control design.

Current Status

BS 7346-1, -2, -3 and -6 were withdrawn as BS EN 12101 published the corresponding harmonised parts. BS 7346-4, -5, -7 and -8 were not superseded and remain current, since they provide calculation methodology and codes of practice that BS EN 12101 does not cover. When specifying smoke control systems, always confirm which parts apply to the project and whether a superseding BS EN 12101 part now takes precedence for any component specification.

Related Standards

• BS EN 12101 - Overview - The European product standard family
• BS 9991 - Fire safety in residential buildings
• BS 9999 - Fire safety in non-residential buildings
• Approved Document B & Building Safety Act - UK regulatory context
• Buy BS 7346 from BSI - Official standard text, BSI Knowledge

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