S05: Sound Masking – Above Green

(2 points)

INTENT

Increase acoustical privacy in open workspaces and between enclosed spaces.

SUMMARY

This WELL feature requires that a dedicated sound masking system is utilized as a means of suppressing speech from other occupants or other distracting sounds by increasing the background noise level evenly throughout a given area.

ISSUE

Levels can vary by zone in a given interior space and at certain times of day or year by 15 dBA or more. HVAC systems do not reliably generate a sound spectrum conducive to speech privacy. Instead, the sound is largely arbitrary and varies considerably from space to space, as well as over time. In some cases, different heating and cooling strategies are employed in the exterior and core, resulting in even more variable acoustic conditions across the space. For projects in warm climate areas, such as Australia, where chilled beam systems are used, the overall level will be dramatically lower than traditional HVAC. Whenever and wherever background sound falls below the 30 dBA on which STC ratings are based, occupants can no longer rely on the partition assembly for speech privacy.

SOLUTIONS

The design of a sound masking system should consider the following for even dispersion across a given zone: sound masking should be evenly spaced, either in a 30- or 60-degree offset, at a distance proportional to the ceiling height and plenum depth; sound masking ideally locates away from building structures and serves the centermost area of the space for the most even coverage; sound masking speakers can be plenum suspended, exposed, directly mounted or beneath raised access floors for best results. The sound emitted by a sound masking system resembles a combination of human speech and human hearing frequency content.

IMPACT

Sound masking is an effective method that, when installed and commissioned correctly, has the potential to bolster acoustical privacy in open workspace and enclosed office environments.

REQUIREMENTS

Part 1

Implement Sound Masking (2 points)

Verified by Performance Test

For All Spaces except Dwelling Units

Sound masking is provided in all of the following spaces and sound levels meet the following requirements when measured from the nearest workstation:

Open offices, libraries, cafeterias, corridors/hallways: 45 - 48 dBA.
Enclosed offices and quiet zones identified through S01: Sound Mapping, Part 3: Label Acoustic Zones: 40 - 42 dBA.