2.2.4. Pressure Relief Dampers for low opening pressures at low range of volume flow KL-ETM

In a great variety of different applications within HVAC systems pressure relief dampers manufactured by Krantz are used to limit the pressure and control it, respectively. Typical applications include the protection of ductwork from inadmissible high loading caused by positive pressure or negative pressure, positive pressure ventilation of staircases, or setting a defined pressure drop between adjacent rooms.




Dimensions W x H x D 250 x 150 x 250 mm
Weight approx. 3.5 kg
Range of volume flow 1 84 l/s [300 m³/h]
Opening pressure, adjustable 50 - 80 Pa 2

1) Higher range flow achivable by parallel Connection of several dampers
2) Higher Opening pressure on request


  • Opens when opening pressure set is attained
  • Almost equal differential pressure independent of range of volume flow (control function)
  • Closes automatically when opening pressure is underrated
  • Setting of opening pressure by variation of restoring mass


It is often required that a defined pressure gradient of 50 − 150 Pa is set between two neighboring rooms. This guarantees a directed flow of air in the leakage ports existing between the rooms and thus avoids the undesired transport of pollutants into the room to be protected. Pressure relief dampers type KL-ETE can be used in this application both as control device for setting a defined pressure gradient between two rooms and as safety valve to set a limit to a maximum admissible pressure value. Depending on available space and range of volume flow to be relieved pressure relief damper type KL-ETE or type KL-ETM is the optimal choice.