Office acoustics: clearer calls and meetings

Glass, smooth walls and desktops reflect speech around the office several times over. The reverberation makes phone calls and meetings tiring, and anyone who wants to be understood speaks louder. Wall absorbers and ceiling elements shorten the reverberation without any building work.

Why is office noise so disruptive?

Employees name noise as the number one source of disturbance in the office, ahead of climate and lighting. Other people's conversations and phone calls are the most disruptive.¹ In experiments, speech at levels as low as 35 dB(A) reduced performance on tasks that rely on short-term memory, such as arithmetic or remembering text. On top of this comes the Lombard effect: when background noise is high, everyone speaks louder. When room acoustics measures bring it down, people speak more quietly again.¹

What reverberation time applies to offices?

The German workplace rule ASR A3.7 sets upper limits for unoccupied offices: 0.8 seconds in single and two-person offices, 0.6 seconds in multi-person offices.² It assigns meetings in conference rooms to activity category I, with a rating level of no more than 55 dB(A); general clerical work belongs to category II with 70 dB(A).² For workrooms with a ceiling height of 2.5 m, DIN 18041 recommends an equivalent sound absorption area of at least 0.25 m² per cubic metre of room volume.³ The VDI 2569 guideline describes how offices are planned acoustically beyond this.⁴

What helps in which office room?

Single and two-person offices need the least: for rooms up to 20 m², ASR A3.7 assumes an average sound absorption coefficient of 0.15.² Wall absorbers on the free wall opposite the desk are the simplest solution here. In meeting rooms, ceiling elements above the table work over a large area, because the ceiling is the largest free surface.¹ Where several people work, desk dividers absorb sound directly between the workstations. Open-plan spaces have their own page: Acoustics in open-plan offices.

Office noise control: room acoustics or sound insulation?

“Noise control in the office” covers two different tasks. Structural sound insulation stops noise from the neighbouring office, the corridor or the street from getting in; walls, ceilings, doors and windows are responsible for this, as set out in DIN 4109. Room acoustics make sure that sound does not echo back and forth within the room itself; DIN 18041 and ASR A3.7 apply here. In most offices, the noise is created in the room itself: conversations, phone calls, keyboards. In that case, sound absorption helps, not sound insulation. Wall and ceiling sound absorbers, acoustic partitions and desk dividers noticeably lower the noise level, with no building work and no tradespeople.

Noise control in open-plan offices and open spaces

In open-plan offices, three building blocks work together. Ceiling rafts above the desk groups absorb reverberation throughout the room, because the ceiling is the largest free surface. Free-standing acoustic partitions and room dividers divide the space into zones, dampen conversations between teams and provide visual privacy, with no building work required. Desk dividers catch speech directly at the workstation, where it is created. This lowers speech intelligibility at the neighbouring desk and makes focused work possible again. There is more about open spaces on the Acoustics in open-plan offices page.

Which sound absorbers suit offices?

• Fiber, made of PET felt, reaches absorption class A (αw 0.9) at 50 mm and is classified B-s1,d0 under EN 13501-1. The practical choice for offices, meeting rooms and call centres.
• Hybrid with Basotect achieves αw 0.95 in the 70 mm element, giving a strong effect on a small area.
• Velvet, with its velvety surface and wide choice of colours, suits reception areas and lounges, but is combustible (class F) and not intended for rooms with fire safety requirements.
• Acoustic art panels with a logo or imagery combine room acoustics and corporate design, for example behind the video call desk.

All wall absorbers are bonded, with no drilling. You'll find an overview under Sound absorbers for walls.

Sources (in German)

1. DGUV: DGUV Information 215-443 Akustik im Büro, March 2021, sections 2, 3.6, 4 and 8.1
2. Ausschuss für Arbeitsstätten: ASR A3.7 Lärm, March 2021 edition, sections 3.16, 5.1, 5.2.1 and Annex 2, Table 3
3. Nocke, Burkart: Überarbeitung der DIN 18041, DAGA 2015, Table 2
4. VDI: VDI 2569 Schallschutz und akustische Gestaltung in Büros, October 2019