Harmony Floor Swirl Diffuser

Harmony FSD

Floor swirl diffuser with high induction, vertically directed swirl discharge with displacement spread across the floor. User-adjustable airflow rate.

Displacement airflow
Thermal displacement room airflow, with low level, high induction mixed flow supply for rapid discharge velocity and temperature differential decay into the occupancy microclimate. Displacement airflow spreads gently across the floor. Heat and contaminants rise by natural convection in thermal plumes to stratify at a high level. Enhanced levels of indoor air quality are attained in the breathing zone.

Floor location
Air supply from the floor, typically at least 900 mm from seated occupants.

VAV dependent throw
Suitable for VAV applications with limited turn-down. Throw height is dependent upon airflow rate.

Manual adjustment
Airflow rate is user-adjustable.

Circular face shape
200 mm nominal diameter round swirl face, plus mounting flange.

Radial face pattern
Radially aligned swirl slots provide high induction swirl discharge.

Plastic face
Polycarbonate, dyed matt black, similar to RAL9005. Other colours available on request subject to order size.

Airflow rate

  • 5.5 – 50 L/s; (20 – 180 m³/h)

Nominal size

  • DN200

Discharge height

  • 0 m


  • Round floor swirl diffuser
  • Vertical air pattern with high induction airflow.
  • Combined damper / detritus tray with user-adjustable damper positioning.
  • User-adjustable airflow setting by diffuser face rotation.
  • Minimum airflow stops at 30%, 35%, 40%, 45%, 50% or 100%.
  • Heavy duty glass reinforced polycarbonate construction, designed to resist central loads up to 400 kg.
  • The mounting arm attached to the trim ring is suitable for rapid and secure press fit installation in raised floor panels.
  • Matt black RAL9005 is standard (other colours on request subject to order size).


The HARMONY Floor Swirl Diffuser, type FSD, is a vertical discharge polycarbonate floor swirl diffuser with vertical discharge and user-adjustable airflow rate from 100% to one of a multitude of preset stops (30%, 35%, 40%, 45% or 50%). Airflow adjustment is by means of rotating the diffuser face. The diffuser is suitable for use in pressurised access floor air distribution systems.

A rapid mount assembly feature provides quick and easy installation or relocation without the need for tools or for access from below.

When cooling, high induction vertical swirl discharge produces intense discharge velocity decay and rapid supply-to-room air temperature equalisation with throw restricted to head height of seated occupants. Cool supply air gently descends to spread as displacement airflow across the floor. An occupancy micro-climate of enhanced indoor air quality is created in which convective currents from occupants and other heat sources rise upwards in thermal displacement plumes. Heat and contaminants stratify in conentrated form at a high level, where they are removed from the space. High levels of indoor air quality and comfort are achieved.

Due to stratification of heat, relatively large supply-to-return temperature differentials are achievable – dependent upon ceiling height – despite the relatively high supply air temperature (typically 18°C), thereby minimising fan energy. Energy savings also accrue from the extended free cooling range often 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 of the occupancy micro-climate.

High induction floor level discharge ensures extremely effective heating performance, due to cool room air, which pools above the floor, being scavanged by the diffuser’s high aspiration, whilst thorough mixing diffuses the warm supply air into the occupancy space.




Face Material

Face Shape

Face Pattern

Product Type


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