When hearing protection and administrative controls cannot be employed to reduce noise exposures, EI’s engineering team assists our industrial clients in the identification and design of noise engineering controls.  Engineering controls for excessive noise can be developed for isolated pieces of manufacturing equipment or entire industrial process lines. Initial steps require performing sounds level facility surveys and personnel noise dosimeter monitoring of manufacturing personnel by experienced industrial hygienists. Noise monitoring results are utilized to determine specific sources of excessive noise, as well as the mechanism of sound generation/propagation emitted by the excessive noise source.  Multiple sources of noise will subsequently be “rank ordered”, which will allow for a range of possible engineering controls, typically addressing the loudest sound sources first.  EI’s professionals segregate excessive noise sources into two distinct classes, vibrational noise and noise turbulence.

Once all specific noise sources are identified, EI utilizes the following logical approach to determine the optimal systems to reduce/control excessive noise:

  1. Substitution of equipment (fundamental first step)
  2. Categorization of source into vibrational noise and turbulence based noise
  3. Reduction of driving forces which cause excessive noise
    a. Decreasing machine speed
    b. Maintaining dynamic balance
    c. Provide vibrational isolation
    d. Increasing impact duration, while reducing the force of impact
  4. Reduce response of vibrating surfaces
  5. Reduce area of vibrating surfaces
  6. Reorienting directional noise sources
  7. Reduction in velocity of fluid flow (air ejection systems, valves, vents and piping)
  8. Provide sound absorption alternatives
  9. Design and installation of equipment and personnel noise enclosures

Let EI’s team of industrial hygienists and engineers work collaboratively to identify and provide cost-effective engineering solutions reduce exposure of your workforce to excessive noise.


EI’s commitment to service has been amply demonstrated on past projects.  Yet again, this commitment has been clearly demonstrated by nimble agility of short notice staff scheduling.  The dedicated professionals of The EI Group have exceeded our expectations.


Steven Pond, CPG

Associate, Schnabel Engineering

Why Your Clinic Should Switch to Insert Earphones

Why Your Clinic Should Switch to Insert Earphones

In a previous blog, a brief history was provided concerning the 30-year effort by hearing conservation professionals to obtain approval from OSHA in 2013 for the use of insert earphones rather than supra-aural headphones. For audiometric testing, Audiologists have used insert earphones in clinical practice for decades. Why should your clinic switch to using insert earphones?

Upcoming Joint CAOHC/NHCA Training Event Series

Upcoming Joint CAOHC/NHCA Training Event Series

The National Hearing Conservation Association (NHCA) and the Council for Accreditation in Occupational Hearing Conservation (CAOHC) are widely recognized as the premier organizations in the United States for the promotion of hearing conservation and training of Occupational Hearing Conservationists. NHCA and CAOHC have partnered to provide a series of webinars covering the basics of hearing conservation.

An Audiologist’s Guide to OSHA’s History with Supra-Aural and Insert Earphones

An Audiologist’s Guide to OSHA’s History with Supra-Aural and Insert Earphones

Well before OSHA’s 1983 Hearing Conservation Amendment mandated audiometric testing for noise-exposed workers, audiometric testing in industry was primarily conducted with supra-aural earphones. The term “supra-aural” means that the earphone sits on the ear. This technology has been around for many years; note the earphones worn by this Air Force bomber pilot during World War II.