Excessive workplace noise is one of the most common and preventable occupational hazards. Prolonged exposure to high noise levels can lead to permanent hearing loss, reduced concentration, and even increased risk of accidents. Because hearing damage occurs gradually and often goes unnoticed until it’s too late, monitoring noise exposure is critical. That’s where noise dosimeters come in! 

What is a Noise Dosimeter? 

A noise dosimeter is a small, wearable device that measures an employee’s total exposure to sound over the course of a shift. Unlike a sound level meter, which measures noise at a fixed location, a dosimeter follows the worker wherever they go, providing a personal record of the noise they actually experience. 

These devices are typically worn on the worker’s shoulder or collar, close to the ear, and continuously collect data. At the end of the shift, the results show not just how loud the environment is, but how long the employee was exposed to certain levels of sound. 

How Do They Work? 

Noise dosimeters use sensitive microphones to capture sound levels and integrate that information over time. The device applies specific thresholds and weightings (based on OSHA or NIOSH standards) to calculate an average exposure level, usually expressed as a “dose” or “time-weighted average” (TWA). 

OSHA sets important benchmarks to help interpret these readings: 

  • Action Level – 85 dBA (8-hour TWA): When exposures reach or exceed this level, employers must implement a formal Hearing Conservation Program that includes employee training and audiometric (hearing) testing. 
  • 5 dBA Exchange Rate: For every 5 dBA increase in noise, the maximum allowable duration of exposure is cut in half, to prevent workers from exceeding the daily permissible limit. 
  • Permissible Exposure Limit (PEL – 90 dBA, 8-hour TWA): Noise exposure above this level requires corrective action. If engineering and administrative controls cannot reduce exposures, workers must be provided with and required to use personal hearing protection devices. 
  • Impulse/Impact Noise: The maximum limit for sudden or impact noise is 140 dB peak. Levels above this can cause immediate hearing damage. 

Why They Matter 

  • Protect Worker Health: Hearing loss is permanent, but it’s also preventable. By identifying high-exposure tasks, employers can implement controls such as noise dampening, job rotation, or personal hearing protection. 
  • Ensure Compliance: OSHA requires monitoring and conservation programs once the 85 dBA action level is reached. Dosimeter data provides documented proof that these requirements are being met. 
  • Targeted Safety Improvements: Results can highlight specific machines, processes, or times of day that present the greatest risks, allowing employers to make focused improvements. 
  • Support Hearing Conservation Programs: Accurate exposure data is the foundation for effective training, audiometric testing, and protective equipment programs. 

Putting Results into Action 

Once noise exposure levels are measured, employers can take steps such as: 

  • Installing noise-dampening materials or equipment enclosures. 
  • Rotating employees to limit time spent in high-noise areas. 
  • Providing and enforcing the use of properly fitted hearing protection. 
  • Conducting ongoing education so workers understand both the risks and the protections available. 

Noise dosimeters are more than just a compliance tool, they are a practical way to protect workers, reduce long-term health costs, and strengthen overall safety culture. By monitoring exposure and acting on the results, employers can create safer, quieter workplaces where employees can thrive without risking their hearing.