LU Insider

Protecting your Hearing from Permanent Damage

Take the time to learn more about sound levels, duration limits, and steps you can take to protect your hearing.

Occupational safety and health professionals use the Hierarchy of Control to determine how to implement feasible and effective controls. This approach groups actions by their likely effectiveness in reducing or removing the noise hazard.

Methods used to control noise levels.

Elimination or Substitution: In most cases, the preferred approach is to eliminate the source of hazardous noise. When elimination is not possible, substitution of the loud equipment for quieter equipment may be the next best alternative to protect workers from hazardous noise.

Engineering and Administrative Controls: To the extent feasible, engineering controls, administrative controls, and work practices shall be used to ensure that workers are not exposed to noise at or above 85 dBA as an 8-hour Time Weighted Average (TWA). Engineering controls require physical changes to the workplace such as redesigning equipment to eliminate noise sources and constructing barriers that prevent noise from reaching a worker. If engineering controls are not feasible, employers an explore potential administrative controls, such as scheduling that will minimize exposure, providing quiet and convenient lunch and break areas.

Personal Protective Equipment (PPE): When all options for eliminating or reducing the noise at the source are exhausted, hearing protection devices such as earplugs or earmuffs should be made available to workers, at no cost, to sufficiently attenuate noise so that their “real-world” exposure is below 85 dBA as an 8-hour TWA.

Sound levels and duration limits.

 Sound level and duration are important to consider when protecting your hearing from damage.

Sound Pressure Level

  • Pressure wave traveling in air or water
  • Expressed in decibels (dB) – It is the perceived loudness
  • Analogy: surface wave made when you throw a stone into a calm pool of water
  • Logarithmic scale
  • Small dB increase represents large increase in sound energy.
  • 3 dB increase is a doubling of sound energy
  • 10 dB increase represents a 10-fold increase
  • 20 dB increase represents a 100-fold increase
Time to Reach 100% of Daily DoseExposure Level per NIOSH RELExposure
Level Lawrence University
Beyond Limits
Protection Required – Noise Reduction Ratio (NRR)
8 hours85 dBA75 dBA – reduced from 85NNR 25
4 hours88 dBA80 dBA – reduced from 88NNR 25
2 hours91 dBA85 dBA – reduced from 91NRR 25 w/ear muffs
1 hour94 dBA85 dBA – reduced from 94NRR 25 w/ear muffs
30 minutes97 dBA85 dBA – reduced from 97NRR 25 w/ear muffs
15 minutes100 dBA85 dBA – reduced from 100NRR 35 w/ear muffs
Noise exposure levels and required personal protection.
Examples of tools and their sound levels by decibels.

Signs of Hearing Loss Include:

  • Frequently asking people to repeat themselves.
  • Turning an ear in the direction of sound in order to hear it better.
  • Understanding conversation better when you look directly at the person. Seeing their facial expression and lips movements can help a someone understand another better is there is a hearing problem.
  • Being unable to hear all parts of a group conversation.
  • Experiencing pain or ringing in the ears (tinnitus).
  • Listening to the TV or radio at volume levels higher than other people normally listen to.

If any of these signs are displayed, a person can take action by visiting an audiologist for a hearing test. An audiologist is a health professional who specializes in diagnosing and treating people with hearing problems.

Video clip of items that produce noise.


Hearing Safety Part 1 – CopperPoint Insurance Companies [8:07]