Open Plan Offices

IRIS can measure open plan office parameters according to ISO 3382-3 [1]:

  • Spatial decay rate of speech: D2,S (dB)
  • A-weighted sound pressure level of speech at 4 m from the source: Lp,A,S,4 m (dB)
  • Distraction distance: rD (m)
  • Privacy distance: rP (m)

IRIS also calculates parameters for classification of large multi-person offices according to German standard VDI 2569 (Draft, 2017) [2].


Please refer to the respective standards for details of required room conditions, measurement positions, and how the various metrics are calculated.

Equipment Requirements

An omnidirectional source is required.

Your IRIS system should be calibrated with the omni-source to measure sound strength (G), as this can be used to determine the speech level at the receiver positions.

A calibrated integrating sound level meter is required for background noise measurements in single octave bands (125 Hz to 8 kHz).

Measurement Paths

Measurements in open plan offices are carried out at a series of workstations which are arranged on a path or line.

  • The sound source should be positioned at the first workstation on the path, and the receiver placed at the remaining workstations on the path.

  • A minimum of 4 receiver positions is required, but the standard recommends between 6 and 10.

    Only positions within the range of 2 to 16 m from the source are used for determining D2,S and Lp,A,S,4 m (enforced in IRIS).

  • At least two source positions are required. If only one path of measurements is possible, the path should be measured twice with the source at opposite ends.

  • The path does not have to be a straight line.

  • If there are multiple acoustic zones in the office (e.g. two areas with different ceiling types), measurements should be made in each zone.

  • The source and receiver should be placed in the position of a seated person’s head, at a height of 1.2 m from the floor.

  • The source and receiver positions should be at least 0.5 m from tables and at least 2.0 m from walls.

[1]International Standard ISO 3382-3 Ed. 1, Acoustics – Measurement of room acoustic parameters – Part 3: Open plan offices (2012).
[2]Verein Deutscher Ingenieure, VDI 2569 Draft, Schallschutz und akustische Gestaltung im Büro (2017).