Retrofitting Sound Masking: The ABC rule

by Niklas Moeller, MBA
Given most employees spend the majority of their time on individual tasks, phone calls, and conversations in their workspace, the workplace should provide them with speech privacy, comfort, and freedom from distracting noises.

When planned during the design phase, creating such an environment is as simple as ‘ABC’—absorb, block, and cover.

As all three strategies are required to achieve the best results, they are collectively referred to as the ‘ABC Rule.’ Any issues arising are typically the result of the omission of one or more of these methods or their imbalanced application within the space. The organization must then determine what treatments will be most effective, the budget available for them, and the degree of disruption they can weather during implementation.

‘A’ is for absorb
Absorptive ceiling tiles, wall materials, and flooring reduce the energy and, therefore, the volume of sounds reflected off their surfaces back into the space.

It is important to specify a good acoustic tile and ensure consistent coverage throughout the facility. The lighting system’s impact on the ceiling’s performance can be limited through selecting an indirect system that incorporates a minimum number of fixtures while still meeting the lighting requirements. Use of hard materials, such as glass and metal, should be minimized because these reflect noise and conversation, causing them to be heard over greater distances. Use absorptive workstation partitions, at least inside and above the work surface. Finally, soft flooring should be installed in high-traffic areas.

‘B’ is for block
Closed plan designs use walls and doors to block sound, but blocking is also a relevant technique for open plans.

Noisy office machines and high-activity areas—such as call centers—should be located in remote or isolated areas. The distance between employees should be maximized, while direct paths of sound transmission from one person to another minimized by seating employees facing away from each other on either side of partitions. Partitions that are 1542 to 1651 mm (60 to 65 in.) high are effective because they extend beyond seated head height, though using taller products in high traffic areas can be beneficial.

‘C’ is for cover
Just as with lighting and temperature, there is a comfort zone for the volume of sound, and it is not zero. Installing a sound masking system helps ensure the facility’s ambient—or background—sound level is sufficient to cover up conversations and incidental noises. It should typically be 40 to 48 dBA, depending on the space.

For optimal results, masking can be applied in both open plans and closed rooms. To ensure the sound will be comfortable, effective, and unobtrusive across the entire facility, volume and frequency can be finely adjusted (e.g. 0.5 dB step volume control; 1/3-octave frequency control across the entire masking spectrum of 100 to 8000 Hz) within small zones of one to three loudspeakers (e.g. 21 to 62.7 m2 [225 to 675 sf]). If paging and music are needed, the designer should ensure both functions can be provided over the same set of loudspeakers. To maximize flexibility, one must specify a networked system allowing changes to be made to zones and settings without accessing the ceiling or altering the cabling.

To read the full article, click here.

Leave a Comment


Your email address will not be published. Required fields are marked *