Hierarchy of Controls for Managing Noise Hazards

Effectively managing occupational noise hazard is a daily activity that involves everyone on the worksite.  Regardless if your work environment is in the general industry or construction industry, the principles of managing noise hazards are the same.  Sometimes easy to accomplish, sometimes not so easy.

Prevention of noise as an occupational hazard can be managed in three ways based upon the Hierarchy of Controls (see below).  This article will focus later on personal protective equipment (lease effective method of the hierarchy of controls) since it is the most common approach to mitigation noise hazards in the workplace.

Hierarchy of Controls

Engineering controls means controlling the hazard at the source.  It includes a physical change to the workplace.  Engineering controls is accomplished with installation of proper equipment or re-designing tools and equipment.

Administrative controls are aimed at reducing employees exposure to noise hazards, but they do not remove the hazard.  This control method requires the worker and employer to do something.  Written work procedures and policies is an example of an administrative control.  Another example would include schedule changes such as rotating employees in high noise areas.  Training employees on occupational noise hazards, the consequences of the hazards along with describing the operational controls to minimize or eliminate the hazard would be considered an administrative control.

Personal Protective Equipment (PPE) is commonly known as the  control of ‘last resort’.   This last resort includes workers to wear something to minimize noise hazards to an acceptable level of risk.  Personal protective equipment for noise hazards include inserts, semi-aural earplugs and ear muffs.

All hearing protectors are designed to reduce the intensity (loudness) of noise to the inner ear.

Hearing protection devices are selected according to:

  • Employee comfort
  • Level of noise exposure
  • NRR of device
  • Type of work being performed
  • Environmental condition

Employee may select hearing protection from a variety of suitable hearing protectors provided by employer.

Let’s now talk about the advantages and disadvantages of each.

1)  Ear Muffs


  • More protection at higher frequencies than earplugs
  • Various NRRs available
  • Durable, long lasting
  • Can be fitted on hard hat
  • Reusable

Ear Muffs


  • Higher cost
  • Eye glasses can interfere with ear muff seal
  • May be uncomfortable in hot environments
  • Must be cleaned before use by another worker

2)  Insert Plugs


  • More protection at lower frequencies than muffs
  • Various NRRs available
  • Inexpensive; disposable
  • Can be custom molded for individual worker
  • Reusable plugs are available Disadvantages

Insert Plugs


  • Hands must be cleaned before inserting earplugs
  • Improper insertion reduces noise reduction rating value

3) Semi-Aural (sometimes called ear caps)


  • Various NRRs available
  • Easy to insert
  • May be used several times
  • Ideal for people going in and out of noisy areas



  • Improper insertion reduces effectiveness
  • More expensive than ear plugs
  • Typically have lower NRRs than plugs or muffs

In closing, there are important factors about utilizing personal protective equipment to mitigate occupational noise hazards.  First, employers must ensure proper initial fitting of personal protective equipment.  This includes demonstration on how to use inserts, semi-aural earplugs and ear muffs (depending on employer decision of what to supply for workers).  In addition, the employer must supervise the correct use of hearing protectors as well as ensure workers understand how to clean and properly store their hearing protectors and when to replace them.

Sometimes the last resort is often the first resort when it comes to managing occupational noise.  When doing so, it is important for both employer and worker to understand the pros and cons of using personal protective equipment.  Hopefully, this article helped shed light on that.

Controlling Noise Hazards Through Engineering Methods

Controlling noise hazards in the workplace can be a time consuming and expensive endeavor.  However, for the sake of worker safety to prevent hearing loss; temporary or permanent, this endeavor is worthwhile and meaningful.  Think of it this way, would you want your son or daughter, spouse or grandchildren exposed to noise hazards without any engineering means to minimize or even eliminate it?

This article will focus on engineering methods of stamping out unwanted noise in the workplace.

The table below shows a few examples of operational controls to consider for various types of noise emissions from specific equipment assets.

Noise in the workplace

Additional engineering control methods to combat noise hazards include;

  • Sound barriers such as a solid wall that blocks the line of sight between a noise source and the worker.
  • Partial enclosure is a series of walls around a piece of equipment that is producing and introducing a noise hazard in the workplace. The top is left open so sound can travel upward, away from the worker.
  • Total enclosure, with a closed top will provide better noise reduction than the partial enclosure. However, workers usually need access capability for visual observation, access to raw materials, removal of scrap, etc.  Therefore, sealing of doors and windows for worker access purposes can include weather stripping material to prevent leakage of sound from around these locations.
  • Machinery Acoustical Shields may be inserted between the worker and the noise emission source that could include all of the machinery or only a specific portion of it. Often this shield is mounted on the machine and can provide 8 to 10 dB of noise reduction.

In closing, unwanted noise is commonly present at construction and general industry worksites.  With the potential of noise-induced hearing loss and additional health effects such as increased blood pressure, narrowing of blood vessels and quicken pulse rate, applicable engineering controls should be looked at extensively.  Feasible and effective engineering controlled methods should be looked at as the “first line of defense” to protect workers’ from the hazards of occupational noise.

Combat Noise Hazards In Workplace

Everywhere you are in the workplace, there is noise.  Exposure to workplace noise hazards can cause permanent hearing loss that can’t be corrected with surgery or even a hearing aid device.  Hearing loss from noise exposure is usually not noticed because it is gradual.  Generally a person loses the ability to hear higher pitches first.

Other hazards that noise contributes to include, but not limited to;

  • Creating physical and psychological stress.
  • Reduce productivity.
  • Reduce product quality.
  • Interfere with communication and concentration.
  • Be a contributing root cause factor in workplace injuries and incidents.

What can be done to reduce noise hazards in the workplace?

Noise in the workplace

Prevention of noise as an occupational hazard can be managed in three ways:

  • Engineer out the hazard. Includes modifying or replacing equipment.
  • Establish administrative controls such as operating noisy machinery during shifts with fewer workers are exposed.
  • Provide personal protective equipment such as earplugs to protect workers from occupational noise.

The best option is to apply engineering methods to either eliminate or minimize the hazard to an acceptable level of risk.  The reduction of a few dB’s can make a world of difference of improving noise related annoyance.

Labels and Sign Do Protect Workers From Noise Hazards

Do workers pay attention to labels and signs in the workplace that specify occupational hazards warnings and caution specifications?  Yes.  Labels and signage should be part of the communication procedure of any employer so that hazards, such as noise, can be repeated and reinforced every day.  The caution of using labels and signs is to not overdue it.  Too many can become a distraction and therefore be avoided by workers to review.

Labels and signs warn workers about noise hazards within their department or specifically at their workstation.   Customizing labels and signage is a great way to increase attention of workers by providing specific job related information about hazards and preventible measures.

Hearing conservation program

The purpose of a hearing conservation program , applicable to both general industry and construction industry, is to lay the foundation of preserving and protecting worker hearing.  A hearing conservation program equips workers with the knowledge and hearing protective devices necessary to protect them from noise emissions.  A few key components of an effective hearing conservation program include:

  • Conducting noise sampling at the worksite that include the use of personal monitoring devices. These devices will indicate which workers are exposed to noise hazards.
  • Informs workers about the risks from noise hazards and the results of the noise sampling process.
  • Provides worker training that educates workers on the purpose and deviation consequences of not complying with engineering, administrative or the use of personal protective equipment. An example would be consequence such as the severity of hearing loss.
  • Ensure proper selection of personal protective equipment based upon individual fit and manufacturer’s testing.
  • Annual audiometric testing program (hearing tests). A professional evaluation of the health effects of noise for individuals exposed to noise hazards, worker’s hearing.
  • Provide worker training on the proper use of personal protective equipment, maintenance and care.

In closing, noise is frequently present in the workplace.  Prevention and mining noise hazards is therefore necessary to protect worker’s safety and well being.  How well this hazard is managed takes both parties; employees and employer, to work together to combat noise hazards in the workplace.

An Introduction to Noise As An Occupational Hazard

Everywhere you are in the workplace, there is noise. Approximately 30 million workers are exposed to hazardous noise while on the job. Noise-induced hearing loss is the most common occupational hazard for workers. The good news is this occupational hazards is 100% pre-ventable.

Prevention of noise as an occupational hazard can be managed in three ways:

1) Engineer out the hazard.
2) Establish administrative controls such as job rotation of employees in high noise area.
3) Provide personal protective equipment such as earplugs to protect workers from occupational noise.

Specifically speaking, occupational noise is most frequently present above the allowable exposure limits; refer to your local jurisdiction, at construction sites and most general industry workplaces.

What is noise and how is it defined? Noise is defined as a sound or sounds that is, loud, unplea-sant and undesired. Noise is simply any unwanted sound. It is a byproduct of industrial process such as operating machinery that either damages or destroys the nerves in the inner ear.

Noise induced hearing loss occurs from overexposure to loud sound. Noise has the potential of causing both auditory and non-auditory health effects, if not controlled properly. Remember, there is no cure for noise-induced hearing loss. This is why conducting a noise survey is neces-sary at all worksites and should be taken seriously by the employer.

Here are a few examples of noise as an occupational hazard:

  • Temporary hearing loss is due to short term overexposure of noise. Hearing returns when you are away from the noise.


  • Permanent hearing loss results from exposure to a moderate or high level of noise over a long period of time. This type of hearing loss does not return when you leave the noise area. Per-manent hearing loss is just that, permanent.
  • Another effect of exposure to high noise levels in the workplace as an occupational hazard would be ‘tinnitus’, permanent ringing in the ear. Tinnitus sufferers usually complain of con-stant whistling, squealing, roaring or bussing in one or both ears. Severe tinnitus may disrupt sleep, reduce concentration and cause irritability and even depression.

Hearing loss from noise exposure is usually not noticed because it is gradual. Generally a person loses the ability to hear higher pitches first.

Signs of hearing loss include asking people to speak louder so that you can hear. For example, do you have to increase the volume of the TV or radio so loud that others complain about it? Common sounds may be louder than you think.Below is an example of what I mean.

Our ears can recover from short exposure to loud noise, but over time nerve damage will occur, The longer and louder the noise, the greater chance permanent damage will occur. Have you heard the saying, “Getting use to it?” When it comes to occupational noise, there is no such thing. You do not get use to it.

Below are two photos that show how occupational noise effect hair cells when not managed cor-rectly.

NoiseIn closing, noise is an occupational hazard that must be managed daily to ensure the safety and well being of workers. Hopefully this article provided some insight as to how noise is defined as an occupational hazard along with the consequences when the hazard is not managed correctly.