Professional Services

We have over 20 years of in-depth experience conducting environmental noise measurements, assessing regulatory compliance, designing noise mitigation, and providing expert testimony.


We have traveled to every corner of the U.S. measuring the noise from industrial sources, including detailed source measurements for sound power level determination, regulatory compliance measurements, ambient noise surveys, and sound transmission loss determination. Our measurement surveys can be as simple as a one-hour test to multi-year campaigns incorporating meteorological data and source systems information. We utilize equipment meeting applicable portions of American National Standards Institute (ANSI) S1 (Acoustics) standards, with current, certified, and traceable calibrations, and we utilize applicable portions of ANSI S12 (Noise) measurement procedures.

  • IEC 61400-11 Acoustic Measurement Techniques for Wind Turbine Generator Systems
  • ASTM E90 Airborne Sound Transmission Loss Test Methods including ASTM E90 within laboratories and
    ASTM E336 and ASTM E966 for existing construction.
  • Also, ASTM E 1007 for impact sound transmission measurements and assessment.
  • ANSI B133.8 Gas Turbine Installation Sound Emissions.
  • ANSI/ASME PTC36 Measurement of Industrial Sound.
  • ANSI S1.13 Methods for Measurement of Sound Pressure Levels.
  • ISO 6190 Measurement of Sound Pressure Levels of Gas Turbine Installations for Evaluating Environmental Noise.

Regulatory Compliance and Permitting

Definition of Regulatory Limits

Noise level limits are not always available and/or it is not always clear how they apply. Some regulations limit the maximum level (Lmax), but then have penalties for tonal noises and allowances for temporary noises. Others will limit the equivalent noise level (Leq) over several hours, or even the day-night noise level (LDN). Then there are limits that don’t seem to have applicable zoning or land uses. We have experience interpreting international (e.g.: World Health Organization, International Finance Corporation), federal (e.g.: Environmental Protection Agency, Occupational Safety and Health Administration, Federal Railroad Administration, Federal Transit Administration, U.S. Department of Housing and Urban Development, Federal Highways Administration, etc.), state (Colorado Revised Statutes 25-12, Colorado Department of Transportation Noise Abatement Guidelines, New Jersey Department of Environmental Protection Chapter 29, New York Administrative Code Section 24, etc), local city and county, and specific energy commission regulations (e.g.: California Energy Commission, Wisconsin Administrative Code Public Service Commission 128, Colorado Oil and Gas Conservation Commission Rule 802, etc) such that our clients clearly understand the noise level requirements and risks to the project, and provide justified and defensible arguments regarding the defined limits.

Acoustical Modeling

We have been predicting and validating acoustical models for over 20 years. Our client's acoustical modeling needs vary from a hand-calculation, custom Excel spreadsheet, federally required Traffic Noise Model (TNM), or SoundPLAN three-dimensional predictions with graphics. Our capabilities allow us to work with conceptual drawings, sketches, CAD, and GIS data as well as the various prediction standards including ISO 9613, Concawe, General Prediction Method, and VDI 3760 to name a few. If needed, we design noise reduction measures and provide conceptual to detailed recommendations to achieve the desired project or client goals.

Compliance Assessments and Mitigation Design

Assessing compliance for a project can involve detailed measurements, acoustical predictions, or a combination of both. For established projects that generate a complaint, we help our clients document those levels, assess compliance, and if necessary, identify and mitigate the primary noise source(s). In many cases, we will replicate noise sources in an acoustical model thus allowing us to efficiently test potential noise mitigation solutions for the client to consider.

We have assessed compliance per a variety of residential, commercial, and industrial standards, as well as performance guarantees by suppliers

Reports and Presentations

Preparing a clear and defensible report or presentation can be critical for a project that is trying to gain the trust of the public, board, or court. We have been successful with our balance of technical details, clear text, and graphics.

Noise Mitigation Design

Depending on the project, the most effective noise mitigation may not be obvious. In some cases, this is due to the project not having a clear understanding of the projects noise limits. Other times we see project “overbuilding” their noise mitigation or planning ineffective mitigations. Our extensive experience has allowed us to be successful in efficient noise mitigation design, including the following:

  • Wind turbine control systems
  • Noise walls and berms
  • Placement of source on parcel and project orientation (i.e. gas compressor stations)
  • Exterior noise - specification of silencers, fans, and construction materials
  • Interior noise – specification of absorption treatments, source controls

Expert Testimony

Our staff have provided expert testimony before public service commission’s for project approval, in municipal court as part of grievance proceedings, and before local agency boards in support of commercial and industrial project approval. We recently testified on behalf of the proposed Highland Wind Farm in Wisconsin, have been involved with lawsuits over gun ranges and clubs and roadways, and presented noise analysis results before the Garfield County, Colorado board in support of a gas compressor station.