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Noise Monitoring Project Experience


Noise exposure is one of the most common occupational health hazards. Noise-induced hearing loss for the employee, along with stress and communication difficulties in the workplace, can impact employee productivity and effectiveness, and the overall health of the employee and company. Our staff has a combined experience of over 75 years of in-depth, hands-on knowledge working with companies to minimize their exposure to noise and SOMA has collected over 25,000 noise samples. SOMA has been providing ongoing workplace monitoring for noise for a number of clients, ranging from small single site employers to large-scale clients with multiple sites distributed nationwide. We have collected noise samples for the following:


  • Mining Industry - Surface Aggregate/Industrial Minerals Mining/Extraction Sites, Underground Mines

  • Utilities Industry

  • Construction Sites

  • Manufacturing Facilities - Industrial Minerals, Cosmetics, Chemical Plants

  • Ready-Mix Concrete Plants

  • Cement Plants

  • Asphalt Plants

  • Road Paving Projects

  • Railroad Operations

  • Commercial Properties


One of our large-scale clients include an aggregates leader with over 300 locations across the United States, Canada, and the Bahamas. Their products include a variety of aggregates, ready-mix concrete, asphalt and cement facilities. SOMA has provided ongoing consulting services (industrial hygiene and occupational health) for this organization for the past 19 years, including a comprehensive evaluation of exposures to noise. We have assisted with ensuring regulatory compliance (MSHA/OSHA) specifically related to noise. The project approach to assess exposures to noise included:


  • Collecting personal noise samples on-site to determine employee noise exposure at the workplace and at times, area noise samples to evaluate community noise exposure.

  • Recording work conditions and existing control measures that may affect the sampling results. We also recorded instantaneous noise levels in the vicinity of the work tasks being monitored to supplement the noise dosimetry when personal dosimetry indicated the potential for elevated noise exposures.

  • Interpreting the measured noise levels and cumulative noise dose. We used state-of-the-art noise measuring dosimeters that datalogged the noise levels and helped identify specific areas of high noise exposure based on the time-based noise data points.

  • Presenting the findings to the client. This has included regular re-evaluation of sampling strategies and prioritization of efforts. The sampling strategy has been refined to identify similar exposure groups (SEGs) and focus on the most at-risk SEGs.

  • Providing recommendations on noise control depending on whether exposures are at or above regulated or permissible exposure levels. The real-time noise level measurement and the review of the datalogged noise levels helped recommend appropriate and effective noise reduction measures from the hierarchy of controls (i.e. engineering, administrative or personal protective equipment). On many occasions we worked closely with on-site personnel, using our noise monitoring equipment and noise-reducing materials with sound dampening properties (insulation, plastic barriers, etc.), and resolved excessive noise conditions while on-site.

  • Developing and maintaining a robust database and generating exposure models based on the existing noise sampling results to predict the employee exposures for others performing similar tasks. The database not only allows tracking of specific SEGs over time, but also records and documents implementation of control measures pursuant to exposure concerns. The exposure modeling experience also allowed us to identify how to best focus the client’s resources to reduce or eliminate noise exposures.

  • In addition to the traditional noise exposure assessment for this client, SOMA has also generated noise maps and plotted noise levels on a plant layout to identify the high noise areas.  

  • The comprehensive approach of evaluating the on-site noise exposures, identifying areas with the potential to exceed regulatory standards, providing recommendations for appropriate control measures combined with tracking the effectiveness of the control measures implemented, resulted in a continuing downward trend of noise exposures for the client. Based on the noise exposure results, SOMA developed the Hearing Conservation Program (HCP) for the client, recommended suitable hearing protection devices and provided appropriate training.

  • SOMA also conducted an extensive evaluation of noise exposure for residential construction workers at multi-site, residential home building locations, for a professional association. This project involved evaluating the noise exposures of workers in several SEGs at residential construction sites and determining the different sources of noise affecting the workers’ exposure. SOMA was also involved in comparing the noise exposures in the residential versus commercial construction environments based on literature survey of peer reviewed, published articles for noise exposure in the construction industry. The results from this study was shared with OSHA during discussion about the development of a new OSHA Noise Standard for the Construction Industry.

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