Learn how to measure, reduce, isolate, mask, and enhance the noise level in different spaces, using some basic principles of acoustics and noise control.

Masking is highly misunderstood and mischaracterized. In hundreds of my design projects the common label it is given by most is "white noise". This is not incorrect and often a fatal flaw in understanding the purpose of masking and how it can be applied, particularly for open offices. While white noise such as a waterfall CAN be referenced and used to mask, it cannot be balanced, controlled, or adjusted in time or spectra. Therefore an electronic method is useful. It is most useful to define masking as "the selective masking of speech consonants" for task concentration and speech privacy. This is completely different from using music or waterfall levels for masking and improves task concentration and speech privacy.

What is the best way to determine the appropriate noise level for a given space?

Noise is one of the most common environmental factors that affects the comfort, productivity, and well-being of people in different spaces. Whether you are designing a new facility, renovating an existing one, or managing the daily operations, you need to consider the appropriate noise level for each space and its users. In this article, you will learn what factors influence the noise level, how to measure it, and how to apply some basic principles of acoustics and noise control to achieve the optimal sound environment.

1 Noise sources and effects

The noise level in a space depends on the type, intensity, and location of the noise sources, as well as the characteristics of the space itself. Noise sources can be internal or external, such as machinery, equipment, ventilation, traffic, or people. The effects of noise can vary depending on the purpose, function, and occupancy of the space. For example, noise can interfere with communication, concentration, privacy, or relaxation, or cause annoyance, stress, fatigue, or hearing loss.

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Allen Wiggill

Principal Acoustic Consultant at SALT-TS
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An important differentiation should be observed between sound and noise. Sound may be described as a specific source or the accumulative sound pressure level in a space, whereas noise is unwanted sound.

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Steve Whitty

Special Acoustic Projects - Building Acoustics Specialist
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Not only noise levels can impact these things but also reverberation has a huge impact on speech intelligibility. We’ve seen many spaces designed for communication with speech intelligibility at just 50% or worse!

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Rodrigo Andrade (安浩荣)

Sales Manager | Business Development | Market Development | Technical Sales | ESG
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One topic that we for sure must consider is the quality of the environment and the type of interference that it may produce in our team during the entire duration of the the workday. That if not properly taken into consideration may lead to reduced performance and stress. Location, facade, equipments nearby, population, all that must be properly calculated for effective results.

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2 Noise measurement and criteria

To determine the appropriate noise level for a given space, you need to measure the sound pressure level (SPL) and the frequency spectrum of the noise. The SPL is expressed in decibels (dB), which is a logarithmic scale that reflects how loud a sound is perceived by the human ear. The frequency spectrum is divided into octave bands or third-octave bands, which indicate the pitch or tone of the sound. Different spaces may have different noise criteria (NC) or noise rating (NR) curves, which are graphical representations of the maximum acceptable SPL for each frequency band.

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3 Noise reduction and isolation

Achieving the goal of acoustics and noise control, which is to reduce the noise level in a space or isolate it from other spaces, can be done by following some basic strategies. These strategies include reducing the noise at the source, such as by using quieter equipment, adjusting the speed or operation mode, and adding mufflers or silencers. Additionally, increasing the distance between the source and receiver works well, such as by relocating the equipment or people. Absorbing sound energy with porous materials like carpets, curtains, or acoustic panels on walls, ceilings, or floors is helpful too. Finally, blocking sound transmission with dense materials like concrete, brick, or gypsum board, or adding mass or insulation to partitions or openings can also be effective.

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4 Noise masking and enhancement

Achieving the desired sound quality and ambience in a space requires additional strategies, such as masking unwanted noise with a background sound like white noise or music, and enhancing wanted noise by amplifying or modifying it. Additionally, balancing sound levels by adjusting the volume, equalization, or distribution of the sound sources and receivers creates a uniform or varied sound field. All of these strategies help to mask or enhance the noise level in a space.

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David Wright

Principal; Senior Acoustics, Noise Engineering & AV Systems Design @ IMEG Consulting Corporation
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Masking is highly misunderstood and mischaracterized. In hundreds of my design projects the common label it is given by most is "white noise". This is not incorrect and often a fatal flaw in understanding the purpose of masking and how it can be applied, particularly for open offices. While white noise such as a waterfall CAN be referenced and used to mask, it cannot be balanced, controlled, or adjusted in time or spectra. Therefore an electronic method is useful. It is most useful to define masking as "the selective masking of speech consonants" for task concentration and speech privacy. This is completely different from using music or waterfall levels for masking and improves task concentration and speech privacy.

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5 Noise assessment and improvement

The final step of determining the appropriate noise level for a given space is to assess and improve the sound environment, based on the feedback and preferences of the users and the stakeholders. This can be achieved by conducting surveys or interviews to collect opinions, complaints, or suggestions regarding the noise level and sound quality. Additionally, measurements or calculations can be performed to compare the actual or predicted noise level with the noise criteria or rating curves, while identifying sources, paths, or receivers of the noise. Finally, solutions or recommendations should be implemented to apply strategies of noise reduction, isolation, masking, or enhancement. It is important to monitor and evaluate the results and impacts of these strategies.

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6 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?

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What is the best way to determine the appropriate noise level for a given space?

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1 Noise sources and effects

2 Noise measurement and criteria

3 Noise reduction and isolation

4 Noise masking and enhancement

5 Noise assessment and improvement

6 Here’s what else to consider

Facilities Engineering

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What is the best way to determine the appropriate noise level for a given space?

1

2

3

4

5

6

1 Noise sources and effects

2 Noise measurement and criteria

3 Noise reduction and isolation

4 Noise masking and enhancement

5 Noise assessment and improvement

6 Here’s what else to consider

Facilities Engineering

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