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AOVs vs. SHEVs in Smoke Ventilation Systems

AOVs vs. SHEVs - When it comes to smoke ventilation systems, two terms often come into play: Automatic Opening Vents (AOVs) and Smoke and Heat Exhaust Vents (SHEVs). While they share the common goal of enhancing fire safety by facilitating the removal of smoke from enclosed spaces, there are nuanced differences between the two. Understanding these distinctions is crucial for designing and implementing effective smoke control strategies in buildings.

Automatic Opening Vents (AOVs)

AOVs are components within a smoke ventilation system that automatically open in response to smoke detection. Their primary function is to provide a designated outlet for smoke to escape, preventing the accumulation of harmful gases within a building during a fire. AOVs are typically installed in areas such as stairwells, corridors, and common areas.

The activation of AOVs is triggered by a smoke detection system or a fire alarm. Once activated, the AOVs swiftly open to create a venting path for smoke to exit the building. AOVs are strategically positioned to align with the natural flow of smoke, ensuring an efficient and controlled evacuation route.

Smoke and Heat Exhaust Vents (SHEVs)

SHEVs, on the other hand, encompass a broader category of components designed not only for smoke extraction but also for heat removal. While AOVs specifically focus on venting smoke, SHEVs are equipped to deal with both smoke and elevated temperatures generated during a fire.

SHEVs often include mechanical systems such as fans and dampers to regulate the airflow. These systems are more versatile and can be programmed to respond not only to smoke detection but also to temperature thresholds. This added capability allows SHEVs to contribute not only to smoke control but also to the prevention of heat build-up, creating a more comprehensive fire safety solution.

Key Differences


  • AOVs are primarily focused on smoke extraction and are activated in response to smoke detection.
  • SHEVs have a dual role, addressing both smoke and heat, and can be triggered by both smoke detectors and temperature sensors.

Scope of Coverage:

  • AOVs are effective in areas where smoke extraction is the primary concern, such as escape routes and common areas.
  • SHEVs are suitable for a broader range of spaces, offering a comprehensive solution for both smoke and heat evacuation.


  • AOVs are generally simpler in design, responding specifically to smoke-related triggers.
  • SHEVs, being more complex, offer a higher degree of customisation and adaptability to various fire scenarios.


In essence, while AOVs and SHEVs share a common objective of enhancing fire safety through effective smoke ventilation, the key difference lies in the scope of their functionality. AOVs are specialised in smoke extraction, whereas SHEVs provide a more comprehensive solution by addressing both smoke and heat. The choice between the two depends on the specific requirements of the building and the desired level of sophistication in the smoke ventilation system.

Collaborating with G.S Stothers ensures a seamless integration of Automatic Opening Vents (AOVs) and/or Smoke and Heat Exhaust Vents (SHEVs) within your building's smoke ventilation system. As industry leaders and dedicated members of the Smoke Control Association, we bring a wealth of expertise and a commitment to compliance with the highest standards. Our specialised teams excel in the design, supply, installation, and commissioning of AOVs and SHEVs, tailoring solutions to meet the unique requirements of each project. Whether it's implementing AOVs for specific smoke extraction needs or deploying advanced SHEVs for comprehensive smoke and heat evacuation, G.S Stothers stands as a reliable partner.

With a meticulous approach, we navigate the intricacies of smoke control regulations, ensuring that your building not only meets but exceeds safety standards. Trusting in G.S Stothers means investing in cutting-edge technology and a dedicated team that prioritises the safety and well-being of building occupants.

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