Regulating and shut-off dampers combine the functions of regulating dampers for precise ventilation adjustment with the ability to fully isolate individual duct branches. They allow supply and extract airflows to be balanced according to design, while also enabling sections of the system to be shut off for maintenance or reconfiguration. This is critical for offices, warehouses and industrial facilities with extensive duct networks.
Key benefits:
Accurate airflow control — regulating dampers for precise ventilation adjustment ensure that each zone receives the required supply and extract air volume.
Complete shut-off when needed — shut-off dampers can fully close a duct section for safe maintenance, cleaning or system changes.
Improved network balancing — proper setting of regulating and shut-off dampers helps eliminate over- and under-supplied areas without major system modifications.
Lower fan energy consumption — a well-balanced duct system requires lower static pressure, reducing electrical power usage.
Flexibility during building lifecycle — when room layouts or functions change, damper positions can be readjusted instead of replacing the ventilation equipment.
Integration with building automation — many damper types are designed for actuator mounting and control via the building management system (BMS).
Regulating and shut-off dampers are installed in supply and extract ductwork at points where precise adjustment or full shut-off of airflow is required. By changing the blade position, the effective opening area is adjusted to increase or decrease the airflow; in the closed position, the duct branch is effectively isolated. This allows the system to reach and maintain the design balance under different operating conditions.
Details:
Regulating function — rotating blades create a controllable resistance in the duct, enabling fine adjustment of airflow in each branch.
Shut-off function — in the fully closed position, shut-off dampers block airflow, isolating sections of the ductwork for service or modifications.
Operation in complex duct networks — regulating and shut-off dampers are installed on mains, risers and branches, taking into account different lengths and resistances.
Adjustment based on commissioning data — during balancing, airflow and pressure are measured and damper positions are corrected step by step to meet design values.
Manual and motorised control options — dampers can be locked in a fixed position or equipped with actuators controlled by the automation system.
Improved acoustic performance — correctly set dampers reduce turbulence, sudden pressure drops and associated noise levels in the duct system.
When selecting regulating and shut-off dampers for precise ventilation adjustment, it is important to consider the system type, airflow and pressure range, tightness requirements and the level of automation. Proper selection simplifies commissioning and balancing, improves energy efficiency and ensures reliable ventilation performance over the entire life of the building.
What we consider when selecting:
Ventilation system concept — constant or variable air volume (VAV), zoning strategy and the role of each duct branch in the overall design.
Airflow and pressure characteristics — damper size, blade design and performance curve are chosen according to expected velocities and pressure differences.
Required shut-off tightness — leakage class and sealing quality are critical where duct branches must be reliably isolated in the closed position.
Automation and control strategy — we determine where manual balancing is sufficient and where motorised dampers with BMS integration are needed.
Operating conditions and materials — air temperature, humidity, dust load and corrosion risk influence the choice of damper materials and coatings.
Installation and service access — solutions are selected to provide good accessibility for inspection, adjustment and routine maintenance of the dampers.
Quality and environmental management Vent System Project OÜ follows the principles of the ISO 9001 certificate.
Regulating dampers are installed in ductwork to adjust and fine-tune the airflow in individual branches and zones. Shut-off dampers are used to fully open or close a duct section when required. Together, regulating and shut-off dampers help balance the ventilation system and control how air is distributed throughout the building.
Regulating dampers are designed for precise air volume control and are intended to operate in intermediate positions. Simple shut-off dampers are mainly used in fully open or fully closed positions for isolation or maintenance purposes. In this product group, you can have combined regulating and shut-off dampers, as well as dedicated shut-off dampers for ventilation ducts.
They are used in supply and extract ventilation systems in office buildings, warehouses, logistics centres and industrial facilities. Regulating dampers are installed on branches and risers where a specific airflow to a room or zone must be achieved, while shut-off dampers are used to isolate duct sections or equipment for maintenance or safety reasons.
Round regulating and shut-off dampers are designed for circular ductwork, while rectangular dampers are used in rectangular ducts. Functionally they serve the same purpose, but they differ in connection sizes, housing design and installation details. The choice depends on the duct system used in the project.
Manual regulating dampers are suitable where airflow is set during commissioning and rarely needs to be changed. Motorised regulating and shut-off dampers are used when airflow or duct isolation must be controlled automatically — for example via BMS, time schedules or sensor signals (CO₂, temperature, occupancy). The decision depends on the required level of automation.
During system balancing, regulating dampers are adjusted so that measured airflows in ducts and rooms match the design values. This prevents over-ventilation of some spaces and under-ventilation of others and helps to achieve a stable indoor climate across the entire building.
Yes. Over-throttled dampers increase air velocity and pressure loss, which can result in noise in ducts and at diffusers as well as higher fan energy consumption. If dampers in one branch are too open, they may draw air away from other branches, disturbing the overall balance of the system.
Dampers are installed in-line with the ductwork using appropriate connectors and supports, ensuring proper sealing and mechanical stability. During design and installation, access for manual adjustment, actuator maintenance and measurement should be considered, often by providing access doors or removable sections near key dampers.
During commissioning and balancing, adjustment is usually carried out by specialised commissioning or service companies using measurement instruments and design documentation. Later, minor corrections can be made by the building’s maintenance staff, but significant changes to damper settings or system layout should be coordinated with designers or commissioning engineers.
The price depends on damper size and shape (round or rectangular), materials, actuator type (manual, motorised, with or without spring return) and order volume. Regulating and shut-off dampers for ventilation systems are supplied for projects in Estonia and, when required, also to Latvia and Lithuania as part of complete ventilation equipment deliveries.
VENT SYSTEM PROJECT OÜ (11720522), Ida-Viru County, Narva City, Narva, Oru tn 4, 20203
VENT SYSTEM PROJECT OÜ (11720522), Ida-Viru County, Narva City, Narva, Oru tn 4, 20203
