About Hessler Associates, Inc.
Hessler Associates, Inc. was formed in 1976 by George Hessler primarily to provide expert design and testing services for simple cycle combustion turbine exhaust systems. Typical projects involved not only the analytical calculations to size the silencer baffles but also the complete general arrangement, fabrication and installation drawings.
This initial focus on gas turbines rapidly widened to include the acoustical design of combined cycle plants and all types of power generation and industrial facilities. Typical projects currently range from the design of combined cycle plants to testing diesel installations powering island nations to the design of data center HVAC systems to environmental impact analyses for wind turbine projects.
David M. Hessler, P.E., INCE
Vice President and Principal Consultant
David Hessler joined the company in 1991 and has extensive experience with the design and testing of combined cycle power stations, diesel/gas engine projects, biomass facilities, wind turbines, landfills, coal plants, and data centers, among many other things.
Mr. Hessler holds a Bachelor's Degree from the University of Hartford in Connecticut and graduated summa cum laude from the A. James Clark School of Engineering at the University of Maryland with a Bachelor of Science Degree in Mechanical Engineering. He is a registered Professional Engineer and a member of Institute for Noise Control Engineering.
Representative Papers and Publications:
- “Wind Turbine Noise”, Chapter 7 Measuring and Analyzing Wind Turbine Sound Levels, Multi-Science Publishing Co., Brentwood, Essex, UK, Jan. 2012. Comprehensive book on all aspects of wind turbine noise. Each chapter written by a recognized expert in that subject.
- “Best Practices Guidelines for Assessing Sound Emissions from Proposed Wind Farms and Measuring the Performance of Completed Projects”, Prepared for the Minnesota Public Utilities Commission under the auspices of the National Association of Regulatory Utility Commissioners (NARUC), Oct. 2011.
- “Accounting for Background Noise when Measuring Operational Noise from Wind Turbines”, Fourth International Meeting on Wind Turbine Noise, Rome, Italy, Apr. 2011.
- “Recommended noise level design goals and limits at residential receptors for wind turbine developments in the United States”, Noise Control Engineering Journal, J.59 (1), January-February 2011.
- “Wind tunnel testing of microphone windscreen performance applied to field measurements of wind turbines”, Third International Meeting on Wind Turbine Noise, Aalborg, Denmark, June 2009.
- “Experimental study to determine wind-induced noise and windscreen attenuation effects on microphone response for environmental wind turbine and other applications”, Noise Control Engineering Journal, J.56, July-August 2008.
Representative Expert Witness Cases:
- Before the Washington State Energy Facilities Siting Board (EFSEC) on behalf of Bechtel and the Cherry Point Cogeneration Project, Bellingham, WA, 2003. Permitting support for a proposed combined cycle power plant facility.
- Before the Public Service Commission of West Virginia on behalf of the Longview Power Project near Morgantown, WV, 2006. Permitting support for a proposed coal-fired power plant facility.
- Before the Pennsylvania Department of Environmental Protection on behalf of Waste Management and the Alliance Sanitary Landfill in Taylor, PA, 2006. Support in defending against a Class Action Lawsuit brought by neighbors of the landfill.
- Before the Office of the Attorney General of New York on behalf of the Hudson Valley Community College Cogeneration (Diesel) Plant. Support in defending against a Class Action Lawsuit brought by neighbors.
- Before the Hanover County (VA) Board of Supervisors on behalf of Martin Marietta Materials and the Doswell Quarry, 2008. Permitting support for a proposed quarry expansion.
- Before the New Hampshire Site Evaluation Committee on behalf of Granite Reliable Power, LLC, 2008. Permitting support for a proposed wind turbine project in Northern New Hampshire.
- Before the Public Utilities Commission of Ohio, Ohio Power Siting Board on behalf of EverPower Renewables and the Buckeye Wind Project, 2008. Permitting support for a proposed wind turbine project in Ohio.
- Before the Wisconsin Public Service Commission on behalf of Clean Wisconsin with regard to the proposed Highland Wind Farm in Forest, WI. Docket No. 2535-CE-100. Engaged as an independent expert to evaluate the Applicant’s sound studies and the testimony of opposition groups.
- Before the Public Utilities Commission of Ohio, Ohio Power Siting Board on behalf of EverPower Renewables and the Buckeye II Wind Project, 2012. Permitting support for a proposed wind turbine project in Ohio.
- Before the Maine State Government Energy, Utilities and Technology Committee on behalf of Patriot Renewables and the Beaver Ridge Wind Project, 2014. Peer review of operational sound testing by others.
George F. Hessler, Jr., P.E., INCE Board Cert.
President and Principal Consultant (Semi-Retired)
Mr. Hessler formed Hessler Associates, Inc. in 1976 to provide acoustical consulting services to the power industry. The firm routinely prepares noise assessment studies for small and large power projects throughout the world ranging in capacity from 1 to 1000 MW. Mr. Hessler has over 40 years of direct experience in the prediction and control of noise emissions from power plant facilities. Early experience was gained as a Senior Project Engineer for a leading manufacturer of noise abatement equipment, followed by a position as Chief Structural and Acoustics Engineer for Turbo Power and Marine, Pratt & Whitney Aircraft, a major designer and manufacturer of combustion turbines. In that capacity, Mr. Hessler was responsible for the control of noise emissions at nearly 300 combustion turbine sites in the U.S. and throughout the world. Many new and innovative acoustic designs were developed for critically sensitive sites during that period.
Mr. Hessler holds a Bachelor of Science degree in Mechanical Engineering from Johns Hopkins University in Baltimore, Maryland. He is a licensed Professional Engineer and is Board Certified by the Institute of Noise Control Engineering (INCE).
Mr. Hessler has written and licenses computer programs used in the industry for predicting sound levels from power plant equipment. Mr. Hessler, along with others in the firm, have published numerous peer-reviewed journal articles and technical conference papers on industrial noise control and acoustics.
Mr. Hessler has been involved for many years in the development of standards relating to acoustics. He is a co-author of ANSI B133.8 “Gas Turbine Installation Sound Emissions”, originally issued in 1972 and since updated several times. This standard is widely used in the procurement process for gas turbines throughout the world. Mr. Hessler is currently the Chairperson for ASA working group 54 to author S12.9 Part 7: “Measurement of Low Frequency Noise and Infrasound Outdoors in the Presence of Wind and Indoors in Occupied Spaces”. This standard promises to be widely used in the measurement of sound during windy conditions, particularly with respect to wind turbine installations.
Although semi-retired, Mr. Hessler, is active in the business on a daily basis and works selectively on projects of special interest.
Representative Papers and Publications:
- “Noise Control Economics of Siting Gas Turbine Power Plants”, Gas Turbine International Magazine, May/June 1977
- “ANSI B133.8-1977: Gas Turbine Installation Sound Emissions”, Co-author, American National Standards Institute, , the American Society of Mechanical Engineers, New York, NY
- “Non-acoustic Design Parameters for Industrial Mufflers”, Proceedings of Noise-Con 81-Applied Noise Control Technology, Presented at the Center for Acoustical Studies, Mechanical and Aerospace Engineering Department, North Carolina State University, Raleigh, North Carolina, 8-10 June 1981
- “Applications and Experience with a Portable Micro-Computer System Controller and Programmable Sound Level Meter/Frequency Analyzer”, Presented at the 107th Meeting of the Acoustical Society of America, Norfolk, VA 6-10 May, 1984
- “On-site Acoustic Privacy Investigation and Corrective Design for a Large Training Center”, Noise Control Engineering Journal, Sep/Oct 1985
- “Gas Turbine Silencing-Then and Now”, Presented at the International Electric Power Industry, Noise Abatement Engineering Workshop, sponsored by BBN Laboratories and the Edison Electric Institute, Cambridge, MA, July 18-19, 1986
- “Predicting Sound Pressure Levels in the Near and Far Field from Radiating Partitions”, Invited Paper, Presented at the Acoustical Society of America Conference, New Orleans, LA, Nov, 1992
- “The Reduction of Low Frequency Combustion Turbine Exhaust Noise – A Case Study”, Presented at the ASME Turbo-Expo ’96, Birmingham, England, June, 1996
- “The Control and Optimization of Environmental Noise Emissions from Combustion Turbine Plants”, Proceedings of the ASME International Joint Power Conference, Pages 512-528, Presented in Houston, TX, October 14-16, 1996
- “HRSG Noise Issues”, Invited Paper, Presented at the Special Session on Power Plant Noise Issues at the joint ASA/INCE-CON 97, Penn State University, June 1997
- “Strategy for Writing Procurement Specifications”, Presented at Noise-Con 2000, Newport Beach, CA, 2000 December 03-05, 2000
- “Certifying Noise Emissions from a Heat Recovery Steam Generator (HRSG) in Complex Power Plant Environments”, Presented at Noise-Con 2000, Newport Beach, CA, 2000 December 03-05, 2000
- “Controlling Noise Impact in the Community from Power Plant Operations – Recommendations for Ambient Noise Measurements”, Noise Control Engineering Journal, Volume 48, Number 5, 2000 Sept-Oct
- “Beware Low Frequency Gas Turbine Noise”, Power Magazine, July/August 2001
- “Proposed Criteria for Low Frequency Noise from Combustion Turbine Power Plants”, Presented at and published in the Proceedings of NOISE-CON 2004, Baltimore, MD, 2004 July 12-14
- “Proposed criteria in residential communities for low frequency emissions from industrial sources”, Noise Control Engineering Journal, Volume 52, Number 4, 2004 July-August
- “Baseline Environmental Sound Levels for Wind Turbine Projects”, Sound and Vibration Magazine, Nov 2006
- “Reducing low frequency boiler stack noise in the community”, Presented at and published in the Proceedings of NOISE-CON 2007, Reno, NV, 2007 October 22-2
- “Experimental study to determine wind-induced noise and windscreen attenuation effects on microphone response for environmental wind turbine and other applications”, Noise Control Engineering Journal, 56(4), July-Aug 2008
- “The Noise Perception Index (NPI) for assessing noise impact from major industrial facilities and power plants in the U.S.”, Noise Control Engineering Journal, 56(5), Sept-Oct 2008
- “Using the Noise Perception Index (NPI) for assessing wind turbine noise”, Third International Meeting Wind Turbine Noise, Aalborg Denmark 17-19 June 2009
- “Using the Noise Perception Index (NPI) for assessing wind turbine noise”, Invited Paper, Presented and published in the Proceedings of INTER-NOISE 2009 in Ottawa, Canada, 2009 August 23-26
- “Measuring ambient sound levels in quiet environments”, Invited Paper, Presented and published in the Proceedings of INTER-NOISE 2009 in Ottawa, Canada, 2009 August 23-2“Proposed ‘Ai’ – Weighting; a weighting to remove insect noise from A-weighted field measurements”, Schomer, P., Slauch, I., Hessler, G., Inter-Noise 2010, 13-16 June, Lisbon, Portugal
- “Recommended noise level design goals and limits at residential receptors for wind turbine developments in the United States”, Noise Control Engineering Journal, 59(1), Jan-Feb 2011
- “A Note on the Debate about Health Effects from Low Frequency Noise (LFN) from Modern Large Wind Turbines”, Presented at the Fourth International Meeting on Wind Turbine Noise, Rome, Italy 12-14 April 2011
- “Criteria for Wind Turbine Noise Immissions”, Co-author with Paul Schomer, An invited paper for the International Conference on Acoustics (ICA 2013) a joint meeting of the Canadian and United States Acoustical Societies presented in Montreal, Canada, June 2-7, 2013
- “Measuring and Analyzing Wind Turbine Infrasound and Audible Immissions at a Site Experiencing Adverse Community Response”, The 5th Biannual International Wind Turbine Noise Conference WTN2013 in Denver, CO, 28-30 August 2013
- “ANSI-S12.9 –Part 7: Measurement of Low Frequency Noise and Infrasound Outdoors in the Presence of Wind and Indoors in Occupied Spaces”, Chairman, Working Group 54 for the Acoustical Society of America, Principal author, Draft 1 slated for distribution by year-end, 2013.
Mark E. Hessler
Technician and Computer Modeling Specialist
Prior to joining Hessler Associates, Mark Hessler worked for a number of years as a sound technician for a variety of, mostly European, television news networks and, in that capacity, traveled widely to cover many major news stories and provide technical support on interviews with celebrities and politicians.
After joining the family business full time in 2001 he has become an expert in using noise modeling software and sound measurement equipment. Mr. Hessler holds a bachelor's degree from the George Washington University in Washington, DC.