The Purpose and Scope of a Noise Survey

Did you know that noise induced hearing loss is a common overlooked occupational hazard to workers?  Did you know that hearing loss is slow and painless; you can develop the disability before you notice it?  Did you know that noise induced hearing loss is 100% preventable?

Noise Survey

Everywhere you are, there is 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?  How is noise defined?  Noise is defined as a sound or sounds that is, loud, unpleasant and undesired.  Noise is a byproduct of industrial process such as operating machinery.  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 necessary at all worksites and should be taken seriously by the employer.  This article will further discuss the importance of conducting a noise survey and how to conduct one.

Audiometric testing

The first step to protect employee hearing is to determine whether or not noise is a potential problem in your workplace. This is accomplished by conducting a noise survey.  A noise survey can be defined as the exploration and understanding of a noise problem that is in question. .  A noise survey is conducted in areas where noise exposure is likely to be hazardous. Furthermore, noise survey is a process which allows the employer to measure, assess and reduce increased, unexpected levels of noise in the workplace.

During a noise survey, a sketch showing the locations of employees and noisy machines is drawn.  A noise survey involves measuring noise level at selected, specific locations throughout an entire plant.  Or, a noise survey may only select a few area of the plant to identify noisy areas.  The reference to noise level refers to the level of sound.

A noise survey is usually conducted with a sound level meter, also known as (SLM).  If the workplace noise remains steady, noise survey data can be used to determine employee exposures. The use of an SLM, helps produce a noise map of the areas within the workplace.

Noise assessment

Noise level measurements are taken at a suitable number of various positions around the area and are marked on the sketch. The more measurements taken during the survey, the more accurate the survey will be.  A noise map can be on the sketch.  Noise survey maps are extremely useful communication tools by clearly identifying areas where a noise hazard exists.

There are five general objectives of the occupational workplace noise survey.  They are as follows:

  1. Identify all significant noise sources and employees likely to be exposed to noise above specified levels (noise exposure standards);
  2. Obtain information on noise sources and work practices that will help the employer decide what measures are to be taken to reduce noise levels in the workplace;
  3. Validate the effectiveness of measures taken by the employer to reduce unwanted noise exposure.  Establish a baseline of assessment results and determine a schedule for future noise assessments to be conducted.The reassessment schedule will be determined by jurisdictional requirements or as described in the employer hearing protection program. Also, it is important to note that a reassessment is to be conducted whenever the following changes occur at the worksite;
  • Installation of new equipment.
  • Removal of existing equipment in the workplace.
  • A change in equipment operating conditions likely to cause a significant change in noise levels, such as increase in equipment speed.
  • A reconfiguration of the building structure that is likely to affect noise levels in a negative way such as taking down a wall that separated equipment operation with non- equipment operation area.
  • Modification of employee working assignments affecting the length of time the employees would spend in noisy workplaces.
  1. Establish hearing protection areas within the workplace. This could include a noise map of the designated areas within the workplace;
  2. Develop a priority assessment to eliminate or reduce sound levels that contribute significantly to the overall daily exposure.

Types of common noise sources in the workplace that the noise survey will identify include:

  • Electric Motors – Air turbulence around intake for cooling fan and mechanical vibration.
  • Pipelines and valves – Vibration from fixed equipment.
  • Equipment Housing – Vibration by transmission of equipment.
  • Stationary power tools– Noisy activities on construction sites include the use of jackhammers, dump trucks, cement mixers, cement cutters, electric saws.
  • Welding and Grinding activities – Grinding noise has been recorded at 103dB, at 5m from the activity.

A noise surveymay be simple or quite complex to conduct.  The difference between simple and complexity depends on the type of workplace, the number of employees, the number and types of equipment as well as information that may already be available, if any, regarding workplace noise exposure levels.

After determining employee exposure to noise, intervention may be needed to reduce noise exposures to the acceptable, allowable levels as described by local jurisdiction.  There are three ways to reduce unacceptable noise exposure, which are in the order of preference:

  • Engineering Controls that reduce noise at the source. Another example of an engineering control method is to reduce reverberation and structural vibration.

When engineering controls are not feasible to reduce noise exposures, administrative controls and PPE should be effectively implemented.

  • Administrative Controls such as employee rotation in high noise areas, report noisy equipment to supervision and place noise specifications on operating equipment.
  • Personal Protective Equipment (PPE) such as hearing protectors such as earplugs or ear muffs.

In conclusion, take control of the noise hazards that are present in your workplace.  Understanding and taking control of your noise monitoring strategy is the only way to ensure that you protect the future hearing capabilities of your employees.  Conduct a noise survey, establish the objectives of a hearing protection program and set the parameters so that the data collected and calculated by the noise surveywill help establish a safer workplace for your employees.

If it is determined that employees within the organisation are exposed to hazardous levels of noise and the organisation issues hearing protection to its employees, then it is mandatory for the employers to submit its employees to undergo hearing test at least once every 2 years.