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Expert Witness


Eric Zwerling, TNC President, has qualified as an expert witness in venues as diverse as: U.S. Federal Court, internationally (Supreme Court of Bermuda), local courts (from Ohio to New Orleans), Planning and Zoning Boards, and a Board of Condemnation Appraisers. His range of expertise includes noise ordinances and their enforcement, facility regulatory compliance determination, sound measurement methodologies, human health and quality of life impacts of noise sources. Mr. Zwerling also serves as the Director of the Rutgers University Noise Technical Assistance Center. In that capacity since 1991, he is contracted by the New Jersey Department of Environmental Protection to provide technical expertise throughout the state. He has trained over 9,000 noise enforcement investigators across the breadth of the United States and internationally, and is extensively published.


Stephen Szulecki, TNC Vice President, has qualified as an expert witness in a numerous venues including: superior court, local courts, land use/planning boards and zoning boards of adjustment. His areas expertise include environmental/occupational acoustical measurements, data analysis, acoustical modeling, designing/evaluating project-specific control strategies,   He excels at explaining the results of his acoustical modeling, and his professorial manner is highly informative and engaging which serves the client very well. His work on a project for Siemens Healthcare resulted in the Consultancy receiving an award.



Acoustical modeling is a powerful "tool" to predict sound emission levels while a project remains in the design phase (pre-construction) or in circumstances where it is important to know how modification to an existing operation will effect sound emission levels.  The predicted sound emissions levels are typically compared to regulatory standards to assess compliance.  Modeling is also used to evaluation potential noise control and mitigation strategies by assessing their efficacy while in the design phase which saves time and money, and results in improved outcomes. TNC owns CadnaA (DataKusiks), an internationally recognized, three-dimensional modeling software. 

Noise Abatement/Control


If your facility is receiving noise complaints -- perhaps your have  been served with enforcement documents -- we can help. We will conduct an acoustical study to determine the specific source of emissions, and evaluate all potential mitigation strategies, often utilizing three-dimensional acoustical modeling. We work with your site engineers, and legal counsel to optimize the solution. In entertainment venues (bars, banquet halls, etc) we can install a monitoring system to allow you to self monitor for compliance. Prior to construction/permitting, we can evaluate your site plans and provide guidance in design and construction techniques to avoid or minimize noise issues. It's infinitely less expensive to design for compliance than to remediate after construction.

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HUD Assessments


HUD’s noise standards may be found in 24 CFR Part 51, Subpart B. For proposed new construction in high noise areas, the project must incorporate noise mitigation features.


All sites whose environmental or community noise exposure exceeds the day night average sound level (DNL) of 65 decibels (dB) are considered noise-impacted areas. For new construction that is proposed in high noise areas, grantees shall incorporate noise attenuation features to the extent required by HUD environmental criteria and standards contained in Subpart B (Noise Abatement and Control) of 24 CFR Part 51. The interior standard is 45dB.

HUD noise studies may also be required by lenders as a condition of funding the project.

Acoustical Studies


We design and conduct sound studies to meet virtually any need whether regulatory compliance, impact analysis, permit application, or occupational exposure, customized to your specific project.

We've been hired to conduct regulatory compliance and other analyses by clients ranging from the Philadelphia Law Department to the Office of the New York State Attorney General to Fortune 500 companies, as well major law firms and individual homeowners.


The hallmark of our sound studies is verifiable precision. Our sound studies employ equipment and methods that meet or exceed the most stringent of requirements, and we document every step, so they're defensible whether used in designing your facility, or presented to a Zoning Board or in State/Federal Court.

Another of our specialties is the forensic analysis of data. We can review the studies and data submitted or relied upon by other experts and determine its validity through a number of analytical methods, including confirmatory acoustical studies. There are many ways to present data, and equally as many to misrepresent it.

Code/Ordinance Development


We've assisted jurisdictions from Alaska to Florida and internationally, offering a full range of ordinance development services ranging from the review of an existing ordinance to drafting an entirely new ordinance, or just a code provision addressing a specific problem. It's important that your ordinance meets the unique needs and goals of your jurisdiction - we listen to you. We offer on-site ordinance development seminars. We can conduct educational or fact-finding meetings with your Law and Police Departments, or with stakeholder residents and the regulated community, it's up to you. We can go "in the field" and visit problem areas and conduct a sound study if needed to develop a code provision addressing a specific issue such as a Special Entertainment District. We've published and taught extensively in the areas of noise enforcement and regulation.

Occupational Acoustics
  • OSHA compliance sound studies

  • Comprehensive HCPs

  • Advanced hearing protection

TNC can conduct the full-array of occupational noise assessments from area monitoring to individual dosimetry, including specialized applications. Based upon the results of the study we can develop a comprehensive Hearing Conservation Program (HCP) for your facility, based upon either the OSHA standards of the more conservative NIOSH guidelines. Often, we can identify problematic equipment or operations whose noise emissions can be managed either through engineering or administrative controls. If the sound emissions are inherent to the source, we can evaluate the hearing protection used by your employees, ensure it is adequate and appropriate, or recommend the appropriate devices.

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NYC E-Designation Studies


New York City Office of Planning establishes "E-designations" for various parcels throughout the city were it has been determined that noise levels resulting from vehicular traffic, train/elevated subway, etc. would cause interior sound levels to exceed 45 dBA, for residential use. The E-designation requires newly constructed or renovated residential buildings to achieve a composite wall-window sound rating that results in an interior level of 45 dBA or less. E-designations were determined based on measurements conducted at various locations throughout the City that may or may not be representative of the noise levels at a specific parcel. The E-designation Rule allows for a property owner to hire an acoustical consultant to conduct site-specific monitoring (generally over a 24-hour period). If the results demonstrate a L10 noise level less than the assigned value, a request can be made through the NYC Office of Environmental Remediation (OER) to modify the E-designation. A lower composite wall-window sound rating allows for the installation of less costly windows/doors while maintaining interior noise at an acceptable level.  

We can conduct an initial evaluate to determine whether conducting a comprehensive site-specific monitoring study will likely yield favorable results, i.e., removal or reduction to the existing E-designation requirements. 

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