Office Acoustics

A question we are frequently asked by Project Managers is how can we improve the acoustical privacy between offices and work stations?

The level of acoustical privacy is defined as the amount of conversation that can be heard and understood between adjacent offices or work stations.

Before we can improve the acoustical privacy we must understand that there are three factors that control the acoustical environment:

– Noise Source
– Type of Partition Between Work Areas
– Level of Background Noise

To improve the acoustical environment in the work place we must determine how these factors relate to one another for each project.

The first factor is the noise source. How loud is the office machinery, the person talking on the telephone next door or the activity that occurs in the adjacent cubicle? This allows us to determine how much noise must be blocked from transmitting from one work station to another.

Next what is the type of partition/barrier/wall that exists between adjacent offices or work stations. Is it a full height wall or a 59” office partition? The partition type determines how much sound will be blocked.

Finally, what is the background noise level in the office. Background noise, as its name implies, is the quietest level of noise heard in an office on a continuous basis. These sounds may include heating or cooling systems, computer and printer fans, the buzz of fluorescent lights, and even traffic noise.

We have found Background Noise to be the most critical variable in this equation. Background noise varies within a building from cubicle to cubicle, office to office, and floor to floor. When you are near core mechanical shafts, where there often are support offices, the background noise heard is usually low frequency, rumbly, duct noise. When you are further away from the core along the duct run, where there are often perimeter offices, the background noise heard is usually the turbulence noise of air traveling through the diffuser.

The challenge is to identify an acceptable level of acoustical noise within the office layout and design.

The acoustical privacy between offices and work stations can be improved by various methods. Each method provides different levels of speech privacy, depending on your needs.

– Gypsum board Ceilings and/or Full Height Wall Partitions for Critical Spaces
– Partitions that Extend into the Plenum for Areas Requiring Confidential Speech Privacy
– Highly Absorptive Open Plan Office Partitions and Sound Masking for Normal Speech Privacy

The first diagram shows how the conversation in Room A can be heard above the background noise level in Room B. The characteristics of this partition type cannot reduce the conversation level below the level of background noise in Room B.

spr293a

In the second diagram, the acoustical privacy level has been improved. Now the characteristics of this partition type can reduce the conversation level below the background noise level. The conversation can no longer be heard in Room B.

spr293b

In future issues we will expand on Speech Privacy and Sound Masking.

(c) Thorburn Associates 1993