During working hours, maximum limit of loudness (expressed as decibels) that workers can tolerate without substantial damage to their hearing is?

Appeared in: NORCET 5 Prelims - Sept 2023 (Shift-1)

Explanation

The established safety standard for occupational noise exposure is 85 decibels (dB) averaged over an 8-hour workday.
This limit is known as the Time-Weighted Average (TWA) and is recommended by agencies like the National Institute for Occupational Safety and Health (NIOSH).
Exposure above this level requires the implementation of a hearing conservation program to prevent Noise-Induced Hearing Loss (NIHL).
For every 3-5 dB increase above 85 dB, the maximum safe exposure time is cut in half.

Option A: 65 dB is the level of normal conversation. While safe, it is not the maximum permissible limit for an 8-hour workday.
Option B: 75 dB is comparable to the sound of a vacuum cleaner. It is well below the action level for hearing damage over an 8-hour period.
Option D: 55 dB is the sound level of a quiet office or a refrigerator hum. This is a very low and safe level of noise, far from the maximum tolerance limit.

Visual 1: Infographic - A decibel (dB) scale chart showing common sounds (whisper, conversation, traffic, jet engine) and their corresponding dB levels, highlighting the 85 dB threshold for workplace safety.
Visual 2: Chart - A graph illustrating the inverse relationship between noise level (in dB) on the x-axis and permissible exposure time (in hours/minutes) on the y-axis.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Occupational Noise Exposure Limits as background academic context rather than a clinical decision trigger.
Occupational health nurses play a crucial role in preventing Noise-Induced Hearing Loss (NIHL) by conducting workplace assessments, educating employees on the use of personal protective equipment (PPE) like earplugs and earmuffs, and performing regular audiometric screenings.
Nurses must advocate for engineering and administrative controls (e.g., enclosing noisy machinery, rotating workers through quieter areas) as the primary methods of noise reduction.
What if the noise exposure is 95 dB? In this case, the maximum permissible exposure time per OSHA regulations drops to just 4 hours. The nurse would need to ensure workers either limit their time in that area or use appropriate hearing protection.

How to Approach the Question

Identify the keywords in the question: 'maximum limit', 'loudness', 'decibels', 'workers', 'hearing damage'.
Recognize that this is a factual recall question related to occupational health and safety standards.
Recall or look for the specific decibel level established by regulatory bodies like OSHA or NIOSH for an 8-hour workday.
Compare the standard value (85 dB) with the given options.
Select the option that matches the established safety limit.

Concept Tested & Keywords

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Practise the full NORCET 5 Prelims - Sept 2023 (Shift-1)

Attempt every question from this paper in a timed mock, then review the full solution for each one.