## **Smoke Ventilation & AOV Systems** Smoke ventilation systems, including **Automatic Opening Vent (AOV)** systems, are critical life safety measures designed to remove smoke and heat from buildings during a fire. In the UK, these systems are regulated by **Approved Document B (ADB)** of the Building Regulations and supported by standards such as **BS EN 12101-2**. --- ### **Purpose of Smoke Ventilation Systems** - Maintain clear escape routes for safe evacuation. - Assist firefighters by improving visibility and reducing smoke temperature. - Limit smoke spread and heat build-up within buildings. - Protect property and structural integrity. --- ### **Main Types of Smoke Ventilation Systems** #### 1. **Natural Smoke Ventilation Systems** **How it works:** Utilizes the natural buoyancy of hot smoke to rise and exit through automatically controlled openings like roof vents, windows, or louvres. **Pros:** - Lower installation and maintenance costs. - No moving parts like fans — less risk of mechanical failure. - Energy efficient. **Cons:** - Relies on effective natural airflow and building design. - Less control compared to mechanical systems. - Limited performance in large or complex layouts. --- #### 2. **Mechanical Smoke Ventilation Systems (MSVS)** **How it works:** Uses powered fans and ducts to extract smoke from common areas, typically via a dedicated shaft or riser system. **Pros:** - Suitable for tall or complex buildings (e.g., multi-storey residential). - Provides controlled, consistent smoke extraction. - Effective even in low wind or pressurised environments. **Cons:** - Higher cost and design complexity. - Requires backup power (often UPS or generator). - Regular specialist maintenance needed. --- #### 3. **Automatic Opening Vent (AOV) Systems** **How it works:** Connected to smoke detectors or fire alarm systems, AOVs automatically open designated vents (rooflights, windows, doors) when smoke is detected. **Pros:** - Fast automatic response to fire events. - Complies with Part B of Building Regs. - Widely used in stairwells, lobbies, and corridors. **Cons:** - May need integration with fire alarm or BMS systems. - Can be affected by obstructions or poor installation. - Requires regular function tests and inspections. --- ### **Common Applications in the UK** - **Apartment block stairwells & lobbies** (to maintain smoke-free escape routes). - **Commercial/industrial buildings** (to reduce risk to life and property). - **Schools, shopping centres & care homes** (to support safe evacuation). - **Underground car parks** (mechanical systems typically used). --- ### **Relevant UK Regulations & Standards** | **Document / Standard** | **Purpose** | |--------------------------|-------------| | **Approved Document B (Fire Safety)** | Legal guidance for designing smoke control systems in new and existing buildings. | | **BS EN 12101-2** | Specifies requirements for natural smoke and heat exhaust ventilators (NSHEVs). | | **BS 9999 / BS 9991** | Fire safety design guidance for commercial and residential buildings, respectively. | --- ### **Maintenance & Testing Overview** To comply with regulations, AOV and smoke ventilation systems must be inspected and maintained regularly by competent persons. Testing typically includes: | **Test Type** | **Frequency** | **Details** | |---------------------------|-----------------------|-------------| | **Weekly Visual Check** | Weekly | Ensure vents are unobstructed and visually inspect control panels. | | **Monthly Functional Test** | Monthly | Simulate fire/smoke trigger to confirm vent operation. | | **Six-Monthly Service** | Every 6 months | Engineer-inspected test of full system operation, including sensors and controls. | | **Annual Certification** | Annually | Full system test with documentation for fire safety compliance. | > 🔧 A maintenance logbook should be kept on-site detailing all inspections, test results, and any remedial actions taken. --- ### **Key Components of AOV Systems** - **Smoke Detectors** – Trigger vents when smoke is detected. - **Control Panels (AOV Controllers)** – Manage activation logic and power distribution. - **Actuators/Motors** – Open vents, windows, or rooflights. - **Manual Override Switches** – Allow fire services or staff to trigger vents if needed. - **Power Supply** – Often includes battery backup or mains-fed supply with failover. --- ### **Common System Layouts (Example)** - **Stairwell Smoke Ventilation:** A single roof vent opens on fire signal to keep the stairwell clear. - **Lobby Ventilation (with shaft):** A vent on each floor opens along with a roof-mounted extract point. - **Mechanical Shaft System:** Central fan extracts smoke via ducts from each floor; often includes dampers and fire-rated enclosures.