In an open-plan office the acoustics decide over concentration and speech intelligibility. ASR A3.7 sets a maximum, DIN 18041 a minimum absorption, ISO 22955 describes office types. The calculator starts with 720 m³ (Multi-person or open-plan office), target value at most 0.60 s, and shows how much ceiling or how many screens from 2,004 products with measured data are needed.
Target values by standard
Target values for an open-plan office in three room sizes. Reverberation time is only part of the assessment; ISO 22955 and VDI 2569 also rate the level decay over distance.
| Standard | Use | 300 m³ | 700 m³ | 1,500 m³ |
|---|---|---|---|---|
| ASR A3.7, workplacesASR A3.7:2021-03 | Multi-person or open-plan office | at most 0.60 s | at most 0.60 s | at most 0.60 s |
| ÖNORM B 8115-3ÖNORM B 8115-3:2023-07 | Multi-person office (Klasse B) | at most 0.55 s | at most 0.55 s | at most 0.55 s |
| SECO guide to ArGV 3, art. 22SECO-Wegleitung ArGV 3, Art. 22 (2021) | Multi-person or open-plan office (Gruppe 2/3) | at most 0.71 s | at most 0.71 s | at most 0.71 s |
| NF S 31-080, officesNF S 31-080:2006 | Open-plan office (performant) | at most 1.00 s | at most 1.00 s | at most 1.00 s |
| SS 25268, offices (Sweden)SS 25268:2023 | Open-plan office (5 or more workstations) | at most 0.40 s | at most 0.40 s | at most 0.40 s |
| SFS 5907, classes A1 and A2 (Finland)SFS 5907:2022 | Open-plan office, furnished (A2) | at most 0.40 s | at most 0.40 s | at most 0.40 s |
| PN-B-02151-4, reverberation and speech intelligibility (Poland)PN-B-02151-4:2015-06 | Open-plan office, bank hall, customer service (A ≥ 1,1 S) | at most 0.44 s | at most 0.44 s | at most 0.44 s |
| LEED v4, acoustic performanceLEED v4 / v4.1 EQ Credit: Acoustic Performance | Open-plan office (with or without sound masking) | at most 0.80 s | at most 0.80 s | at most 0.80 s |
| ISO 22955, open-plan officesISO 22955:2021 | Mostly individual work (accounting, engineering, programming) (Typ 4) | at most 0.50 s | at most 0.50 s | at most 0.50 s |
Typical measures
- Full-area class A acoustic ceiling: the only surface that works everywhere.
- Ceiling rafts or baffles above team zones when the ceiling is occupied.
- Upholstered screens and cabinet walls between the zones.
- Carpet and soft furniture lower the level, but do not replace zoning.
Frequently asked questions
What reverberation time applies in an open-plan office?
Under ASR A3.7 at most 0.6 s, averaged over 500 and 1,000 Hz. For room group B4 DIN 18041 requires a minimum absorption of A/V from 0.25 m⁻¹ at room heights up to 2.5 m.
Why is reverberation time not enough as a criterion?
Because in an open plan the sound from the neighbouring zone disturbs, not the reverberation of the whole room. VDI 2569 and ISO 22955 therefore also rate the level decay with distance.
How many ceiling rafts does an open-plan office need?
Without a continuous acoustic ceiling, around 60 to 80 percent of the floor area in class A absorbers. The calculator names the quantity per product from the measured curve.
Other room types
Formulas, DIN 18041 and worked example on the calculator page