Available in different sizes, the SPI is an iris damper designed for measurement and adjustment of the airflow. The SPI has a low sound level, centrically formed air flow and fixed test points for precise measurements. The device can be used for both air supply and extraction.

The damper is manufactured from galvanised sheet steel and is fitted with a rubber gasket. The gasket has been tested for air-tightness in class C according to EN 1751. An adjustment aperture allows for opening the entire cross-section, so no access door is required for necessary cleaning.

The SPI adjustment damper must be installed in accordance with the distances required to minimise airflow deviation. Reducing or enlarging the duct to the next duct size does not require any specified distances for minimising the deviation. The SPI enables taking precise air-flow measurements at all points, including points close to T junctions and bends and points in front of air ducted or terminal devices.