Auditorium Displacement Diffuser

Smartemp ADS-FD

Step displacement diffuser for low turbulence displacement airflow from steps in tiered auditoria and lecture theatres.

Displacement discharge
Thermal displacement airflow, with low velocity. low turbulence supply from the step face beneath auditorium seats into the occupancy microclimate. Heat and contaminants rise in plumes by natural convection to stratify at a high level. Enhanced levels of indoor air quality are attained in the breathing zone.

Wall location
Air supply from vertical step face.

VAV dependent throw
Suitable for VAV applications. Horizontal coverage dependent upon airflow rate.

Fixed direction
Marginally inclined discharge for reduced ankle zone velocities.

Rectangular face shape
Nominally 120 mm high by 500 mm. Bespoke sizes available on request. With our without face flange.

Perforated face pattern
Round holes with 60° stagger. Bespoke patterns available on request.

Metal Face
Aluminium frame and perforated metal face powder coated to colour of choice.

Airflow rate

  • ≤60 L/(s · m); (216 m³/(h · m))

Sound power level

  • ≤15 dB(A)


  • Available with or without face flanges


  • Variable


  • 100 – 300 mm


  • 70 mm


  • For auditoria and halls with steps
  • Diffuser built into step front
  • With face flange – standard
  • Without face flange – optional. Ends may abut for continous look.
  • Optional concealed fasteners available
  • Slightly upward inclined, low velocity, low-turbulence displacement dispersion near floor
  • Low sound power level


The SMARTEMP Auditorium Displacement Diffuser, type ADS-FD, is a step displacement diffuser suitable for location in the vertical face of auditorium steps. The rectangular diffuser face may be flanged or flangeless. A low velocity, slightly upward inclined, low turbulence airflow pattern is discharged from a perforated face, which is made of powder coated galvanised steel.

Displacement airflow oozes from the perforated step face with minimal mixing to produce a low velocity, low level lake of high quality air that floods the floor around each seat. The slightly inclined discharge pattern minimises air velocities in the ankle regions of seated occupant, to prevent draughts. A low level occupancy microclimate of enhanced indoor air quality is created, in which convective currents from occupants and other heat sources rise upwards in thermal disacplacement plumes. Heat and contaminants stratify at a high level in concentrated form, where they are removed from the space. Replenishment air is drawn by convection from the low level lake, enveloping heat sources in cool, high quality air.

Due to stratification of heat, relatively large supply-to-return temperature differentials are achievable – dependent on ceiling height – despite the relatively high supply air temperature (typically 19°C), thereby minimising fan energy. Energy savings also accrue from the extended free cooling range typically achieved by the elevated supply air temperature, as well as from the potential to reduce outdoor airflow rates due to the enhanced indoor air quality achieved by the improved ventilation effectiveness of the low level step displacement supply.

Airflow Direction




Product Type

Face Material

Face Pattern

Face Shape

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