Acoustic Standards for Open-Plan Offices: A Deep Dive into BS ISO 22955

Open-plan offices have become a staple in the modern workplace, designed to promote collaboration and communication.

However, the spacious, open nature of these environments can lead to excessive noise levels when multiple conversations, keyboard clicks, and foot traffic blend together.

If left unchecked, this can create a stressful and distracting atmosphere that undermines the very benefits open offices aim to promote.
Recognising this, the British Standards Institution (BSI) developed BS ISO 22955:2021 to guide the optimisation of acoustic conditions in open-plan offices.

BS ISO provides this information in two formats: as ‘general principles’ for open-plan acoustic treatment and by reference to six ‘room types’ with example recommendations.

Read on to learn about the impacts of untreated noise in open-plan spaces and how to optimise your space to comply with the BS ISO standard.

Why do open-plan offices need acoustic treatment?

The idea behind open-plan offices is to create a collaborative, communicative environment where ideas flow freely and teamwork thrives. But there’s a catch: noise pollution.

Without acoustic treatment, noise bounces off hard surfaces like desks, floors, and ceilings, creating an echo chamber. Suddenly, your colleague’s phone call from across the room sounds like it’s right next to you. The clatter of keyboards becomes a constant backdrop to your workday.

This isn’t just a minor annoyance, either. Studies have shown that this kind of noise pollution can have some serious consequences:

• Dissatisfaction and irritability: A survey conducted by the University of Sydney found that most employees in open-plan offices are dissatisfied with noise levels, detracting from the purpose of open spaces (e.g. collaboration and communication).
• Stress and fatigue: Noise directly affects their health, with work environments significantly contributing to stress, fatigue, loss of attention, and headaches. For instance, a study from the University Medical Center Mainz showed that long-term exposure to noise levels above 55 decibels could lead to elevated stress levels, cardiovascular disease, and hearing impairment.
• Productivity loss: Workplace noise distractions also lead to lost productivity. Orosound cites that each employee can lose an average of 30 minutes daily due to noise-related annoyance. This translates into a financial loss for companies annually.

These studies and numerous others highlight why ISO developed specific standards for open-plan office spaces.

Now, let’s move on to explore BS ISO 22955:2021’s recommendations and how to apply them.

 

General principles of open-plan office acoustic treatment

BS ISO 22955 defines several general principles and methods of treating open-plan offices, which include:

1. Ceiling treatments

Ceiling treatments are pivotal in acoustic management, especially in open-plan offices where hard surfaces exacerbate noise.

Implementing ceiling solutions can dramatically reduce sound reflection and reverberation, key factors in improving overall acoustic quality. High-performance acoustic tiles, baffles, and rafts are central here.

Effective acoustic ceiling treatments for offices include:

• Acoustic tiles: Designed to fit within standard suspended ceiling grids but generally offer superior sound absorption rates than conventional ceiling tiles. Common materials include mineral wool, glass wool and recycled polyester.
• Ceiling baffles: Ideal for offices with high ceilings or where a suspended ceiling isn’t feasible, baffles hang vertically, increasing the surface area for sound absorption.
• Acoustic rafts: Similar to baffles, rafts can be especially effective in areas where ceilings are congested with lighting and services. They offer flexibility in design and can be aesthetically pleasing while providing the highest levels of sound absorption.

2. Wall treatments

While walls may not offer as large an area for treatment as ceilings, strategically fitting them with sound-absorbing materials on walls can reduce echo and reverberation.

Popular office acoustic wall treatments include:

• Acoustic panels: Available in a variety of materials, including fabric-wrapped fibreglass and foam, these panels can be custom-designed to complement the office’s style while providing robust sound absorption. Placement at critical reflection points boosts their effectiveness.
• Stretched Fabric Systems: These systems cover larger wall areas and can discreetly incorporate high-performance acoustic materials into the office design. The fabric is stretched over a frame, concealing the acoustic insulation within.
• Direct-to-wall applications: Though often less aesthetically pleasing than other approaches, acoustic plaster or spray-on cellulose can be applied directly to wall surfaces.

3. Floor treatments

Solid, sound-reflective floors increase noise levels through impact sounds such as footsteps, particularly in offices with high footfall. Installing sound-absorbing materials, such as carpets, rugs, or acoustic underlay, can significantly reduce impact noise transmission.

Common floor treatments include:

• Carpeting with acoustic underlay: High-density carpet tiles with specially designed acoustic underlays can reduce footfall noise and provide a degree of sound absorption.
• Acoustic floor mats: A more comprehensive solution, acoustic mats can offer targeted noise reduction in high-traffic areas or beneath noisy equipment, mitigating the transfer of impact sound to other office areas.

4. Integrated solutions, décor and space planning

In addition to ceilings, walls and floors, BS ISO 22955:2021 makes several recommendations for planning open-plan offices and installing décor to minimise noise.

Key points to consider include:

• Acoustic furniture: High-backed sofas, pod-like meeting spaces, and desk dividers with sound-absorbing properties can help control noise. However, the standard states this is seldom enough to obtain optimal acoustic treatment.
• Acoustic screens: Acoustic screens are an effective solution for reducing noise distractions in open-plan offices. These panels work by absorbing and blocking sound, thus limiting the distance that noise can travel. The screens should be tall enough to block the direct path of speech between workstations and extend above and below desk surfaces.
• Space planning: The layout of an open-plan office affects the acoustic environment. The standard suggests that workstations are grouped based on levels of collaboration, whereas other areas, like meeting rooms, are placed in adjacent rooms with sound-isolating doors.
• Room geometry: The standard recommends a relatively low ceiling height compared to the floor area. Avoid higher ceilings than normal, as they can amplify sound propagation. Similarly, long and narrow room shapes should be avoided, as they can create an echo effect that exacerbates noise distractions.

Open-plan office acoustics

And there we have it: a quick summary of the BS ISO 22955:2021 standard for open-plan offices.

It’s an important piece of documentation, as open-plan offices, while popular, can suffer from serious noise issues that impede their very purpose: building a productive, collaborative environment.

If you’re looking to improve the acoustics in your open-plan office, contact our team for a free onsite acoustic survey.

We’ll assess your current office space, identify areas for improvement, and recommend solutions to create a thriving, productive workplace.