VAV for Fume Cupboards
Energy-Saving airflow control systems for modern laboratories
Variable Air Volume (VAV) Control Systems
VAV (Variable Air Volume) control systems work by dynamically adjusting the airflow through each fume cupboard in response to its sash height. When the sash is raised, the VAV controller opens a fast-acting motorised damper in the duct above to increase extract airflow, maintaining the correct face velocity across the opening. As the sash is lowered, the damper closes to reduce the airflow accordingly. This ensures operator safety while significantly cutting down on the volume of conditioned air that must be supplied to the room to replace extracted air.
Substantial Energy Saving
By only extracting as much air as necessary, rather than running at full volume continuously, VAV systems offer substantial energy savings. This is especially impactful in laboratories with multiple fume cupboards, where the cumulative reduction in extract demand lowers the load on heating, cooling, and air handling systems.
Safe Fume Dispersal
To ensure fumes are adequately dispersed at roof level, a bleed damper is commonly fitted into the extract system. When fume cupboard sashes are lowered and less air is extracted from the lab, the bleed damper opens to introduce additional air into the system, maintaining a steady volume and preserving the terminal velocity at the discharge stack.
Benefits of VAV Control
Significant energy savings
VAV systems reduce extract airflow when sashes are lowered, minimising the amount of heated, cooled, or conditioned air that must be replaced – dramatically lowering HVAC energy usage.
Smaller extract and supply systems
By designing to an agreed diversity level, a limit on how many fume cupboards can be in use with their sashes fully open at any one time, we can size the ventilation plant for realistic peak use rather than worst-case extremes. The result: lower installation costs and a smaller, more efficient extract and supply air system.
Enhanced user safety
VAV systems constantly adjust airflow to keep fume cupboard face velocity within safe limits, no matter the sash position or how many cupboards are in use. This ensures full compliance with BS EN 14175 and gives users consistent, reliable protection.
Lower carbon footprint
Reduced energy demand translates to fewer emissions, supporting sustainability goals and easing BREEAM or LEED compliance.
Flexible and future-proof
VAV systems are ideal for laboratories with multiple fume cupboards or changing usage patterns, adaptively responding to real-time demand without the need for major system upgrades.
VAV Integration & Control
Our Variable Air Volume (VAV) systems are fully compatible with modern Building Management Systems (BMS), supply air systems and room controllers.
By integrating seamlessly with your building’s infrastructure, our systems help maintain the required number of air changes per hour (ACH) and ensure correct room pressurisation relative to adjacent areas, essential for safety, containment, and energy efficiency.
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