Office designers have a tough task on their hands: Employees demand privacy and confidentiality, but designers have to optimise the amount of space to their disposal – a consideration that favours open-plan design. Open-plan design also helps to improve the interaction between employees.
Unfortunately creating acoustic comfort in open-plan spaces is always a challenge. The intrusion of unwanted sound is one of the leading sources of workplace dissatisfaction, but an office that is too quiet can leave employees feeling unnerved and anxious. The ideal situation is when the confidentiality of employees is protected, but a non-intrusive background “buzz” is maintained.
Large glass surfaces look fantastic in open plan offices, but they are not conducive to creating the ideal acoustic environment. Glass and other large, hard, smooth facades result in sound being reflected back at the same angle it hits the surface.
The sound bounces back and forth until it is exhausted, resulting in long reverberation times and noise levels so high that people find it hard to concentrate. This process of sound reflecting back to the source is called reverberation and it describes the persistence of a sound even after its source has stopped.
To counter this, techniques that deflect, direct, spread and absorb sound can be employed on walls, ceilings and floors, as well as furnishings.
The type of activities being carried out in the workplace and the office culture also play a role in determining the ideal acoustic environment. Acoustic treatment will therefore always be unique to the workplace in question.
- Also read our blog Quick and Easy way to estimate reverberation.
Here are eight practical tips for good acoustic design in open plan offices:
- Fit angled or sound diffusing elements to walls, especially those opposing glass facades, windows and other hard reflecting surfaces.
- Angle the glass/hard surfaces by a minimum of six degrees to prevent sound being bounced back at exactly the same angle.
- Angled walls can help to reflect sound towards the ceiling, trapping some of the sound and reducing the reverberation time and the general noise level.
- Install sound absorbers such as Knauf’s Cleaneo Up and Cleaneo Adit to the ceiling and the walls, or consider using acoustic plasterboard such as Knauf’s Stratopanel in new projects.
- Erect screens between desks in office landscapes to absorb/diffuse sound and keep noise to a minimum. If people need to make lots of phone calls as part of their work, a screen next to them can prevent the conversation from being broadcast to the rest of the room.If you sit behind a screen and slowly stand up, you might notice that the sound from the other side of the screen gets louder as you get closer to the top edge of the screen. This shows that some of the sound is deflected, and the deflection should be taken into account when screens are used.
- Protrusions and baffles on walls or ceilings are good at catching stray sounds. Stray sounds are created when soundwaves bounce around the room when reflected from surfaces.Baffles are good at preventing sound propagation in large rooms, and are effective when combined with screens in open plan offices, for example. But baffles in rooms designed for speech can create problematic echoes.Privacy in open plan offices can be enhanced by combining room dividers with barriers in the ceiling and diffusers on the walls.
- Another way to dampen sound is to mask it. This method involves using a white noise machine or incorporating natural element such as a water feature. The white noise created by these elements calms the listener and masks unwanted sound. It can be useful in open plan offices where lots of telephone calls are going on at the same time, or other distracting activities are taking place.
- Zoning is an important consideration when designing an open-plan office, which means matching the acoustics to the function of the designated space. It helps to know in advance what kind of activity will take place in that room, but this is not always possible. In buildings with individual offices, the corridor is the link between the offices and the other rooms. The corridor should also incorporate an acoustic adjustment or zoning between the rooms.
- Knauf’s Stratopanel Linear offers easiest and fastest installation of high-performance acoustic plasterboard to give great sound absorption. Stratopanel Linear has the same outstanding qualities as the standard Stratopanel range, but requires no glue or jointing compound during installation. And with a precise fit between boards, with the v-joints become almost invisible when painted.
- Knauf’s Reverberation Time Calculator is a useful tool to calculate the recommended reverberation time as per AS/NZS 2107: 2016 and to estimate the Reverberation Time (RT60, RT or T) of a room.
- Download our Acoustic Design for Workplaces e-book for further discussion and advice.