In this article, we delve into the acoustic considerations for open office plans, a topic of increasing importance as more companies adopt this layout. We'll explore the key factors that influence the acoustics in these environments.
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ASTM standards for open office plans
Several interrelated factors affect the desirability of acoustics in open-plan offices. ASTM standard E1374-18 [reference 1] describes general office acoustical considerations and lists all ASTM standards relevant to office acoustics design. This section is a quote from the standard, with some editing for brevity.
Signal-to-noise ratio—Noise intrusion and the level of acoustic privacy between workspaces in open plans are determined by the degree to which the sounds from nearby workspaces exceed the background sound levels.
Sources other than speech generate the level and spectrum of background sound at the listener’s ear. Electronic sound masking systems offer the best means of raising the ambient sound level in a tunable (optimized) manner to ensure predictable levels of speech privacy where insufficient levels of continuous minimum background sound exist.
Absorption – In the open-plan office, the goal is to maximize attenuation with distance in order to improve sound isolation. This may require a highly absorptive ceiling, some absorption on the floor, and careful treatment of some vertical surfaces. Absorption reduces sound reflections and reverberation, which contributes to acoustic comfort.
Sound barriers – Sound passing through, over or around a physical barrier will be reduced in level. Barriers, such as workstation partitions, are an essential part of open-plan acoustical design.
Layout - The open office plan layout must consider the needs for isolation and concentration or collaboration and ease of communication between workstations.
Undivided workspaces – Collaborative open office design has all but eliminated vertical barriers in order to foster communication and interaction between coworkers. For job functions requiring freedom from distraction in the open plan, it may be achieved with the inclusion of appropriate sound barriers. In open spaces with workstation partitions below seated head height, acoustical performance may be improved by the addition of acoustical absorption and sound masking, but an expectation of speech privacy or significant noise isolation is unrealistic in this circumstance.
Intrusive noises - Distractions caused by raised voices or noisy equipment may not be sufficiently controlled by open office constructions. Care should be exercised in elimination or minimizing the noise generation aspects. Open office etiquette guidelines should be established and enforced.
ISO Standards relevant to open plan office acoustics
ISO standards provide alternative approaches to the ASTM standards. ISO 22955 [2] provides guidelines on the factors contributing to acoustic quality in open offices.
There important acoustic quantities (among others) described in the standard are quoted in the Ecophon [3] document [4].The acoustical consultant decides whether the ASTM, ISO, or both standards are best suited to a specific project.
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