Control

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Can we control the noise?

Under Work Health and Safety Legislation in Australia, a duty holder is required to work through the hierarchy of control measures when managing the risks associated with hazardous noise in the workplace.

A workplace must always aim to eliminate the risks arising from hazardous noise, and if it’s not reasonably practicable, it must minimise the risks so far as is reasonably practicable.

The most effective control measure in the hierarchical structure for noise control is to eliminate the source of noise completely. This can be done by ceasing to use a noisy machine, or by changing work practices so hazardous noise is not produced.

Minimising the risks associated with hazardous noise in the workplace can be affected by such methods including, substituting plant or process to reduce noise (i.e., buy ‘quiet’ policy, changing the way the job task is done, or replacing ototoxic substances with other less harmful products), and isolating or separating the hazard or hazardous job task from any person exposed to it (i.e., locating noise sources further away from workers or using remote controls to operate noisy plant from a distance).

Engineering controls are physical control measures to minimize risk, and involve modifying equipment, process, or the environment in some way so that less sound energy is created or is transmitted to the workers.

Administrative controls are designed to lower the noise exposure by limiting the time workers spend in high noise areas. These measures are often necessary when engineering controls are not feasible or cost effective.

If all practicable noise control measures have been exhausted, and the noise remains above the WES, suitable Hearing Protection Devices (HPDs) must be issued.

Further information and guidance on controlling the risk of hazardous noise can be found in: The Safe Work Australia (SWA), Code of Practice (COP): Managing hazardous noise and preventing hearing loss at work’ (2018), and AS/NZS 1269.2 Occupational noise management – Noise control management.

Key Takeaways

Controlling noise:
- Is considered the most effective method to reduce the noise hazard.
- Can be done by specifying quiet equipment during process design, using engineering controls or implementing administrative controls.
- May allow a company to reduce the number of employees in a hearing conservation program.

Benefits of Controlling Noise

A duty holder that controls noise through various methods may benefit in numerous ways:
- Reducing the risk of noise-induced hearing loss (NIHL) and associated health effects among workers
- Eliminating or reducing the cost and time spent on implementing a Hearing Conservation Program (HCP) when workers noise exposure is reduced below 85 dB(A) or 140 dB(C) as a result of noise control efforts.
- Decreasing overall reliance on hearing protection devices (HPDs)
- Enabling more options for suitable hearing protection devices.
- Helping improve face-to-face and radio communication because there is less background noise to interfere with speech.
- Easier to comply with Work Health and Safety Legislation on occupational noise exposure
- Showing commitment to workers that the PCBU is serious about reducing noise hazards

Getting Started With Noise Control

Although you may choose to consult with a noise control engineer to assess your situation and design solutions, it is extremely beneficial to involve the workers who work in noisy areas as part of a team working to find ways to lower the noise. A consultant can bring tremendous technical knowledge but the people who spend each day immersed in the noise can provide some of the most practical and straightforward solutions because they know the processes and equipment so well.

Step 1. Measure workplace noise.

It might seem obvious, but the process of controlling hazardous noise in the workplace cannot really begin until the workplace has completed a noise hazard assessment and analyzed the results. By monitoring noise in different areas of the facility and by conducting Noise Assessments on different processes, tasks and tools, a duty holder will collect the data necessary to identify groups of workers and areas where noise controls are most needed and prioritize where and how to spend noise control dollars to get the greatest benefit. Then, a more detailed noise control survey can be done to identify the noise sources and select the most appropriate noise control solution.

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Step 2. Buy Quiet

Making equipment and processes less noisy during design and fabrication is more effective and economically efficient than implementing noise controls afterward. Buy Quiet is a type of Prevention through Design approach which places a priority on eliminating or controlling the hazard by specifying machinery or tools that create less noise. This is accomplished when a new production processes is being designed or when older equipment or processes are replaced.

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Step 3. Decide which noise sources pose the greatest hazard

Prioritising the potential noise control projects is an important step towards achieving the most economic outcome. While it may seem logical to focus attention on the highest noise source in your facility, it is possible that you can achieve a more significant decrease in employee noise exposures by first controlling noise in the areas closest to where a large percentage of your workers are working. Some noise controls are fairly inexpensive and, when successful, can gain tremendous support from workers and management.

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Step 4. Consider noise control options
If eliminating the noise hazards and associated risk isn’t reasonably practicable, the next step is to minimize the risk by applying one or more of the following controls:
- Substitution controls may include replacing a hazard or hazardous work practice with something that gives rise to a lesser risk. This can include substituting plant or processes that are quieter, or replacing ototoxic substances with other less harmful products
- Isolation controls may include isolating or separating the hazard or hazardous work practice from any person exposed to it. This can include isolating the source of noise from people by using distance, barriers, enclosures and sound absorbing surfaces, building enclosures or soundproof covers around noise sources, using barriers or screens to block the direct path of sound, locating noise sources further away from workers and using remote controls to operate noisy plant from a distance.
- Engineering controls are physical control measures utilised to minimise the risk. Engineering controls include modification of plant and processes to reduce the noise. This can include eliminating impacts between hard objects or surfaces through cushioning or separation, fitting silencers to compressed air exhausts and blowing nozzles, fixing damping materials (such as rubber) or stiffening to panels to reduce vibration, and fitting sound absorbing materials to hard reflective surfaces.
- Administrative controls may be less complicated from a technical point of view but can be disruptive if extensive changes to work schedules and workflow are involved. It is not necessarily difficult to establish time limits for employees working in certain areas or doing specific tasks, but enforcement of such limits may create additional complexity in your HCP. Examples include organizing schedules so that noisy work is done when only a few workers are present, providing quiet areas for rest breaks for workers exposed to noisy work, and using job rotation to limit the time workers spend in noisy areas.
- PPE controls do not control the hazard at the source and rely heavily on human behavior and supervision. Hearing protection devices (HPDs) consist of earplugs and earmuffs, and should be used when the risk arising from the exposure to noise cannot be eliminated or minimized by other effective controls, or as an interim measure while other control measures are implemented, or when additional protection is needed above what has already been achieved using other control measures for excessive noise.
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Step 5. Evaluate feasibility
According to AS/NZS1269.2, when setting treatment priorities, the key issues are the feasibility of various noise control measures and their respective costs and benefits. Demonstrating that a certain noise control solution is technically feasible may be fairly straight forward but documenting the economic feasibility can be a challenge.

Some questions to consider are:
- Is the decrease in the sound level that can be achieved with a certain noise control significant enough to justify the cost relative to the cost of a hearing conservation program?
- What is the estimated benefit in terms of lower noise levels, reduced risk of hearing damage, improved communications and safety, and improved working environment?
- What are the up-front costs of installation, and the long-term costs of maintaining the control(s)?
- What effect will the controls have on the processes in our facility and the workflow? How will that impact efficiency?
Weighing up all significant factors, selecting the best treatment options and determining treatment priorities based on the relative severity of each noise problem will provide you with a foundational and prioritized treatment list for your noise control plan.
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Step 6. Evaluate effectiveness of controls

Perform noise measurements once controls are in place and periodically afterwards to verify and document the results. Establish a schedule to monitor the effectiveness of noise control materials and mechanisms as they age and, potentially, deteriorate over time due to wear and tear. Whenever changes are made to processes and production, review what the effects may be in terms of existing noise controls.

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Requirements

What is Required?

Work Health and Safety Legislation in Australia limit a worker's noise exposure to LAeq,8h of 85 dB(A), referenced to 20 µ Pa (averaged over an 8-hour exposure) or C-Weighed peak sound pressure level of peak exposure of 140 dB(C) referenced to 20 Pa. A PCBU must limit the 8-hour noise exposure of workers to 85 dBA or below using noise controls and also have the option to use HPD's when other control are impractical or excessively costly.
Using Hearing Protection in Place of Controls
If noise controls fail to reduce sound levels to the required Workplace Exposure Limit (WES) or below, a duty holder must provide and select hearing protection devices (HPDs) that minimize risks to worker health and safety by ensuring that it is:

suitable for the nature of work and hazard associated with the work

a suitable size, fit, and is reasonably comfortable for the worker to wear, and

effectively maintained, repaired and replaced when required, as well as clean, hygienic and in good working order

Individual fit of personal hearing protectors is critical for optimum protection. 3M strongly recommends fit testing of hearing protectors as an indicator of the noise reduction obtained by individual worker. OSHA, NIOSH and the National Hearing Conservation Association (NHCA) have endorsed hearing protector fit testing as a best practice.

principles of noise control can be carried out at the source, along the path, and at the receiver

Basics of Noise Control

In the most basic sense, limiting the noise exposure of workers can be accomplished by applying controls to the noise Source, the noise Path or the Receiver.

Source
Source modification addressed the root cause of a noise problem. The noise source is a vibrating object—a machine or tool creating vibration during operation that radiates into the work area as noise. Source noise can be treated via modification, retrofit, substitution and relocation.

Path
Control of the sound transmission path only addresses the symptoms of noise. Noise travels through the air, of course, but also through solid materials such as floors, walls and windows. Path noise control treatment includes partial barriers, surface treatments and enclosures.

Receiver
Receiver treatment is the most practical for job tasks that are conducted in one location and confined in a relatively small area. In hearing conservation, the receiver is the worker. Receiver noise control treatment aims to reduce the workers noise exposure via acoustically treating the space or worker area.

Examples of Engineering Noise Controls
Engineering controls involve modifying the equipment, process, or environment in some way so that less sound energy is created or is transmitted to the workers. Often, the most effective approach is to identify and treat the source of the noise, based on the results of a noise control survey.

Source

Maintain tools and equipment routinely (such as lubricating gears, replacing gaskets, etc.)

Reduce vibration where possible

Modify the process or method of production such as changing:

Speed

Pressure

Mechanical controls

Direction of air flow

Path

Isolate the noise source using springs or pads to prevent noise from traveling through floors or walls

Enclose the noise source

Place a barrier between the noise source and the worker

Isolate the worker from the source in a room or booth

Install sound absorbing materials to minimize direct sound transmission or reflection

Receiver

Use video monitors or remote controls to allow workers to operate equipment at a location farther from noise sources

Retrain workers to use tools or complete tasks in ways that create less noise

Require workers to wear hearing protection
Examples of Administrative Noise Controls
Administrative controls are designed to lower the noise exposure by limiting the time workers spend in high noise areas. These policies are often necessary when engineering controls are not feasible or cost effective.

For example, a workplace can adopt a Buy Quiet approach, specifying less noisy equipment and processes during the design phase. However, when eliminating the noise is not feasible, there are approaches to lowering the risk of noise-induced hearing loss, either through engineering a solution or applying an administrative policy to limit noise exposure.

Source

Operate noisy equipment and processes when fewer workers are present—for example at night

Turn off noise sources in between tasks or when workers are present

Path

Restrict access to noisy areas

Receiver

Rotate workers in and out of noise during the day

Set time limits for certain tasks or use of noisy tools

Require workers to wear hearing protection

Types of Controls

Noise control images used courtesy of Associates in Acoustics, Inc.

Isolation
Springs, foam or other damping materials are used to reduce the transmission of sound from noise sources to floors, walls or connected equipment.

For example, springs on each support of a floor-mounted motor to lessen the sound energy that is passed into the floor and the rest of the building.
Damping
Placing materials such as foam, resin or tape on an object or modifying it so that it vibrates less.

For example, coating the outside of a metal bin with resin to reduce the vibration made when parts are dropped into the bin
Reflection
Barriers or partitions are placed in the sound path to deflect sound away from employees

For example, placing a wall or enclosure around a compressor so employees can work nearby with less direct noise exposure
Substitution
Replacing or modifying components of a noisy system to make less noise

For example, switching to a quieter air nozzle or replacing steel wheels on a cart with low-noise rubber wheels
Modification
Changing a process to make it less noisy

For example, decreasing the distance that parts much drop into a bin so less noise is created
Absorption
Sound-absorbing materials placed in an area to reduce the reflection and buildup of sound

For example, acoustical tiles place on a hard surface to lower sound reflection in a room

Beyond the Basics

The benefits of effective noise control (described above) can be expanded by implementing a Buy Quiet policy.

Why Buy Quiet?
One of the most cost-effective ways of reducing noise in a workplace is to 'buy quiet'. Purchasing quiet products can reduce noise levels without additional modification to equipment or the workplace. Specifying less noisy tools and processes during the design phase may help duty holders avoid costly noise controls once long-term purchases and commitments have been made.

Benefits of Buy Quiet
- Reducing the risk of hearing loss
- Reducing the long-term costs of audiometric testing, personal protective equipment, and workers compensation. This savings is applicable across a wide variety of machinery and equipment.
- Compliance with The Safe Work Australia (SWA), Code of Practice (COP): Managing hazardous noise and preventing hearing loss at work’ (2018), and AS/NZS 1269.2 Occupational noise management – Noise control management.
- Reducing the impact of noise on the community.

Have You Considered?

- Having a “noise control contest” by engaging your maintenance workers to come up with solutions to noise problems identified by your workforce?
- Controlling the leaks in systems that use compressed air to save on energy costs as well as reducing the noise exposure?
- How much does your hearing conservation program cost annually per worker? How much can you save by reducing the noise exposure below the action level?
- Starting a “buy quiet” policy so that no additional noise sources are introduced into your production areas?
- Setting a goal to do one or more noise control projects per year?
- Measuring the noise after a noise control is implemented to track the success of the project?
- Creating a log of all the noise control projects?
- Updating employee noise exposure records to reflect the new results and when they took effect?
- Making a strategic plan to lower noise exposures over time, tackling the highest priorities first?

Resources to Learn About Noise Control

Noise, SafeWork Australia
See “Codes and Guides” tab links to: Model Code of Practice: MANAGING NOISE AND PREVENTING HEARING LOSS AT WORK: October 2018.
This page also includes links to State and Territory Regulators for specific local requirements

The Australian Standard AS/NZS 1269 series, Occupational noise management (1 – 4), provides technical requirements and guidance on all facets of occupational noise management.

CONTINUE YOUR HEARING CONSERVATION JOURNEY: PROTECT

IMPORTANT NOTE: This information is based on selected current national requirements. Other country or local requirements may be different. Always consult User Instructions and follow local laws and regulations. This website contains an overview of general information and should not be relied upon to make specific decisions. Reading this information does not certify proficiency in safety and health. Information is current as of the date of publication, and requirements can change in the future. This information should not be relied upon in isolation, as the content is often accompanied by additional and/or clarifying information. All applicable laws and regulations must be followed.