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2025-04-03 18:34:47 R. Bishop: -/-| /dev/null .. smoke ventilation.md | |
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| + | ## **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**. |
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| + | --- |
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| + | ### **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** |
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| + | #### 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. |
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| + | --- |
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| + | #### 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. |
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| + | --- |
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| + | #### 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. |
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| + | --- |
| + | |
| + | ### **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). |
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| + | --- |
| + | |
| + | ### **Relevant UK Regulations & Standards** |
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| + | | **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: |
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| + | | **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. |
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| + | --- |
| + | |
| + | ### **Key Components of AOV Systems** |
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| + | - **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. |