Master the principles of smoke control system design including natural ventilation, mechanical extraction, and pressurisation systems to BS EN 12101 standards.. Why Smoke Control Matters Smoke is the primary cause of death in building fires, accounting for over 80% of fire fatalities. Effective smoke control systems are essential for protecting means of escape, facilitating firefighting operations, and reducing property damage. The design of these systems requires a deep understanding of fire dynamics, building geometry, and regulatory requirements. Types of Smoke Control Systems Natural Smoke and Heat Exhaust Ventilation (SHEV) SHEV systems use buoyancy driven flow to exhaust smoke through roof vents or high level openings. Design considerations include: Aerodynamic free area of ventilators Inlet air provision (replacement air) Smoke reservoir depth and clear layer height Wind effects on performance Activation mechanisms (automatic and manual) Mechanical Smoke Extraction Mechanical systems use powered fans to extract smoke from the fire compartment or common areas. Key design parameters: Extraction rate (typically 3 10 m³/s per fire zone) Ductwork sizing and fire rating Fan specification (rated to 300°C or 400°C for 1 2 hours) Make up air provision System resilience and redundancy Smoke Pressurisation Systems Pressurisation systems maintain positive pressure differentials to prevent smoke ingress into protected spaces such as stairways and lobbies. Design to BS EN 12101 6 requires: Minimum pressure differential of 50 Pa (doors closed) Maximum door opening force of 100 N Air release provisions when doors open Variable speed drive fans or pressure relief dampers Consideration of stack effect in tall buildings BS EN 12101 Standard Series The BS EN 12101 family covers all aspects of smoke control: Part Subject Part 1 Smoke barriers Part 2 Natural SHEV Part 3 Powered SHEV Part 4 SHEV installation Part 5 Guidelines for functional requirements Part 6 Pressure differential systems Part 7 Smoke duct sections Part 8 Smoke control dampers Part 10 Power supplies Part 13 Pressure differential systems — design calculation methods Design Process A systematic approach to smoke control design includes: 1. Fire risk assessment — identify the design fire scenarios 2. Performance criteria — define clear layer height, visibility, temperature limits 3. System selection — choose the appropriate smoke control strategy 4. Preliminary design — hand calculations using zone models 5. Detailed design — CFD modelling for complex geometries 6. Specification — component selection and system integration 7. Commissioning — hot smoke testing or equivalent verification 8. Maintenance — ongoing inspection and testing regime Common Design Challenges Atria and Large Open Spaces Smoke filling in atria is governed by the balance between smoke production (plume entrainment) and extraction capacity. The Zukoski, McCaffrey, and Thomas plume correlations are commonly used, but CFD analysis is often necessary for complex geometries. Car Parks Car park smoke control typically uses impulse (jet) fans to create directional airflow, channelling smoke towards extraction points. BS 7346 7 provides specific guidance for car park ventilation systems. Residential Common Corridors Smoke ventilation of common corridors in residential buildings has been a focus since Grenfell. BS 9991 requires either natural AOV systems or mechanical ventilation, with specific provisions for single stair buildings. Magnus Opifex SEVEN LTD's Smoke Control Services Our team designs and reviews smoke control systems for projects ranging from simple residential buildings to complex mixed use developments. We combine hand calculations, zone modelling, and CFD analysis to deliver optimal solutions that meet both regulatory requirements and practical buildability constraints. Magnus Opifex SEVEN LTD — UK's Leading Fire Safety & Fire Engineering Consultancy 🌐 magnus opifex.co.uk 📞 +44 7486 691724 ✉️ office@magnus opifex.co.uk Founders: Nicoleta Vasile, Baroness of Brattleby — CEO, Lawyer and Barrister, Legal & Administrative Director Alina — Technical Director & Expert Fire Engineer (BEng) Head Office: Ealing Cross, 85 Uxbridge Road, London W5 5BW Magnus Opifex SEVEN LTD delivers engineering led fire engineering, fire risk assessments, CFD modelling, and building safety consultancy across the United Kingdom and internationally. With over 20 years of combined experience and a UK portfolio spanning healthcare, residential and infrastructure, we bring truly engineered solutions with a personal touch. © 2026 Magnus Opifex SEVEN LTD. All rights reserved.