Occupational Soundscapes – Part 1: An Introduction to Noise-Induced Hearing Loss

     Exposure to excessive noise in the workplace can have profound effects, both immediate and long-term.  Some consequences are obvious, while others may surprise those that have not studied the topic.
     Some industries, such as mining and construction, are subject to regulations published specifically for them.  This series presents information, including regulatory controls, that is broadly applicable to manufacturing and service industries.

     Several parallels exist between exposure to noise and heat stress (see the “Thermal Work Environments” series).  These include the relevance of durations of exposure and recovery, the manifestation of cognitive, as well as physical, effects on workers, and the importance of monitoring exposure and risk factors.
     To take advantage of these parallels, the “Occupational Soundscapes” series follows a path similar to that taken in the “Thermal Work Environments” series.  Terminology, physiological implications, measurement, and guidance for managing the risks are each discussed in turn.
 
Terms in Use
     The title “Occupational Soundscapes” was chosen to maintain the focus of the series on two important aspects.  First, “occupational” reminds readers that the subject matter context is the workplace.  Managing sound and preventing occupational noise-induced hearing loss (NIHL) – hearing loss caused by workplace noise – is the objective of the series.  This differentiates occupational hearing loss from other causes.  Other forms of hearing loss can occur in addition to NIHL; these include:

• presbycusis – naturally-occuring due to aging.
• sociocusis – caused by recreational or non-occupational activities, such as music, aviation, motorsports, or arena sports.
• nosocusis – caused by environmental factors such as exposure to chemicals, behaviors such as drug use, or underlying health conditions such as hypertension.

These types of hearing loss are presented to provide clarity to occupational causes, but will not be discussed in detail.
     The second term of the title, “soundscapes,” serves to remind readers that workplaces are filled with a combination of sounds; some are desired, others are detrimental to working conditions.  Each contribution to the soundscape has a unique source and set of parameters.
     Much of this series focuses on the reduction, control, and protection from noise – the unwanted portion of the soundscape – but readers should not lose sight of the wanted sound.  One very important reason to control noise is to maintain accessibility of desired sounds.  Speech communication is of particular importance and is the primary focus of audiometric testing and industrial noise-control regulation.
     In its “Criteria for a Recommended Standard – Occupational Noise Exposure, Revised Criteria” (1998), NIOSH declares that its focus is on prevention of hearing loss rather than conservation of hearing.  This emphatic declaration is somewhat bizarre, as this is a distinction without a difference.  The terms are functionally equivalent, particularly in practical matters, to which “The Third Degree” is committed.  Readers will be spared a detailed explanation of why this is true; suffice to say that references to hearing loss prevention, hearing conservation, and hearing preservation are considered interchangeable.
 
     While paralleling the information presentation of the “Thermal Work Environments” series, the objectives pursued in this series will also mimic those of its predecessor series.  In brief, each installment is limited in scale and scope to be palatable to busy practitioners, easily referenced, edited, or expanded as future development requires it.  To further promote a holistic approach to job design, the two series should be read as companion pieces.  Side-by-side review of thermal and aural requirements of a workplace may reveal complementary or synergistic solutions, increasing the efficiency of industrial hygiene improvement efforts.
 
     Links to the entire series are provided at the end of this post for easy reference.
 
     For additional guidance or assistance with Safety, Health, and Environmental (SHE) issues, or other Operations challenges, feel free to leave a comment, contact JayWink Solutions, or schedule an appointment.
 
References
[Link] “Criteria for a Recommended Standard - Occupational Noise Exposure, Revised Criteria 1998.”  Publication No. 98-126, NIOSH, June 1998.
[Link] ”29 CFR 1910.95 - Occupational noise exposure.’  OSHA.
[Link] Kodak's Ergonomic Design for People at Work.  The Eastman Kodak Company (ed).  John Wiley & Sons, Inc., 2004.
 
Jody W. Phelps, MSc, PMP®, MBA
Principal Consultant
JayWink Solutions, LLC
jody@jaywink.com
 
Directory of “Occupational Soundscapes” entries on “The Third Degree.”
Part 1:  An Introduction to Noise-Induced Hearing Loss (26Jul2023)
Part 2:  Mechanics of Sound and the Human Ear (9Aug2023)
Part 3:  The Decibel Scale (23Aug2023)
Part 4:  Sound Math (6Sep2023)
Part 5:  Audiometry (20Sep2023)
Part 6:  Measurement of Sound Exposure (4Oct2023)