The aroma of coffee fills the air, two colleagues discuss the next project – and you’re expected to focus on a complex data analysis. In open-plan offices, different working styles converge. While this has many advantages, it also presents challenges – especially when it comes to acoustics.

So how can disruptive noise in offices be effectively reduced without compromising the open-space concept? ISO 22955 offers practical answers – and we show how to apply them in acoustic office planning.

Why acoustics matter in open-plan offices

Employees in open workspaces are significantly more exposed to disruptive sounds than those in private offices. Phone calls, impromptu meetings, running coffee machines – all of these can seriously impact concentration.

Modern spatial planning therefore increasingly relies on acoustic zoning: defining and designing distinct areas for communication, retreat, and focused work in a way that minimizes mutual interference. This is precisely where ISO 22955 comes into play.

What is ISO 22955?

Published in 2021, ISO 22955 complements existing standards for office acoustics, such as ISO 3382-3 or VDI 2569. It specifically targets multifunctional, open-plan office environments where different activities take place simultaneously.

A central concept of the standard is the “spatial decay of speech” (DA,S) – the difference in speech sound pressure level between a lively communication area in the open space and a more sensitive receiving point, such as an individual workstation. Depending on the function of each area (communication vs. concentration), the standard defines different target values. The maximum recommended level is 32 dB (e.g., between a coffee point and a focus area).

Which measures are actually effective?

In a case study, various acoustic shielding solutions were simulated – including single-layer curtains, multilayer textile panels, and glazed partitions with doors. The results make it clear: not all measures are equally effective.

Key findings at a glance:

• Single-layer curtains offered only minor improvements.
• Multilayer curtains significantly improved the situation but failed to achieve the 32 dB target in all areas, especially at short distances.
• Glass partitions with doors achieved the best results – though they are only partially compatible with open-space concepts.
• Acoustic ceilings were also examined. They help reduce reverberation time and improve overall acoustic conditions but cannot replace targeted shielding between work zones.

Simulation results in focus

“Heatmaps” from the acoustic simulations illustrate how the various shielding measures affect speech decay (DA,S). Four variants were tested – each with and without an acoustic ceiling.

The outcomes:

• Without any barrier, sound reduction remained below the recommended threshold, even with ceiling absorbers.
• Single-layer curtains improved DA,S by about 4 dB – insufficient for quiet workstations.
• Multilayer curtains achieved up to 10 dB improvement but still fell short of the target in some zones – mainly due to open, technically necessary gaps between the curtains and adjacent structures.
• Fully enclosed glass walls with doors achieved DA,S ≥ 32 dB in all work areas, regardless of the ceiling – thus fully complying with the standard, though often in conflict with the open-space design principle.

The simulations clearly show: selecting the right barrier is crucial – especially at short distances between lively and quiet zones. While curtains can offer moderate improvements, their effectiveness depends heavily on the sealing of joints – a critical but often overlooked practical factor.

The most effective solution proved to be glass walls. They meet the highest acoustic requirements, but conflict with the flexibility expected from open-plan environments.

Practical recommendations for office planning

Acoustic office design doesn’t start with furniture – it starts with a well-thought-out zoning strategy. Based on the simulation findings, the following actions are recommended:

Implement clear zoning
Physically separate communication-heavy zones (e.g., kitchenettes, lounge areas) from concentration areas. Communication and retreat zones should not be placed side by side. Buffer zones with low noise sensitivity can help prevent functional conflicts.

Use mobile partitions
Curtains or movable walls can be effective – provided they are acoustically efficient and carefully installed (including attention to gaps and junctions).

Complement with sound absorption
Acoustic ceilings improve the overall room acoustics and reverberation time – but they do not replace barriers between work zones.

Use standard-based planning
In-situ speech decay (DA,S) is a key planning parameter of ISO 22955 – and a valuable tool for differentiating the acoustic quality of open-plan offices. The standard provides practical reference values and helps balance openness with protection from noise.

Conclusion

Good acoustics require foresight – and adherence to clear planning standards.
With proactive design, thoughtfully applied measures, and a bit of office etiquette, modern open-plan offices can live up to their promise: spaces for collaboration and communication, as well as quiet retreats for focused work – flexible, adaptable, and vibrant.

This article is based on the expert study “Practical Application of ISO 22955 for Acoustic Design in Open-Plan Offices” by Eva Wassermann (Müller-BBM Building Solutions GmbH), presented at the 51st Annual Meeting on Acoustics (DAGA) on March 20, 2025, in Copenhagen.

Read the full paper on ISO 22955 and open-plan office acoustics here.

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