ATCO Structures & Logistics (ASL) was initially engaged to create a noise mitigation plan for the proposed Astoria Energy power facility. ASL conducted site noise measurements and used the results, combined with manufacturer provided noise levels and data from ASL’s own library of measured noise levels, to determine the acoustical impact of the plant without mitigation. ASL used these results to design a mitigation solution that would ensure that after completion of both power blocks, the plant would not exceed noise regulations.
After providing design, material supply and quality assurance for the noise control for the first power block of the project, ASL was engaged to supply and install all noise control for the second power block of the 1,100 MW facility.
ASL used its proprietary acoustical wall and roof assemblies for the second power block’s 3,600 square metre turbine hall, the fuel gas compressor and gas-insulated switchgear enclosures. ASL also designed, supplied and installed a freestanding acoustic wind wall, 33 metres tall and 182 metres long and installed custom-designed ventilation silencers.
ASL’s scope included supply and install of all structural steel, concrete panels and slabs, HVAC, electrical, doors, partitions and ceilings, and two overhead bridge cranes.
Technical Information:
The combined noise sources for both power blocks of the Astoria power plant include:
• Four GE 7FA gas turbine generator units
• Two Alstom steam turbine generator units
• One 24-cell Air Cooled Condenser (ACC) unit
• Two HRSG units with exhaust stacks
Acoustical Performance Target:
The project’s location fell under the jurisdiction of four different noise codes:
• New York City Zoning Resolution
• New York City Noise Code
• New York City Environmental Quality Procedure
• New York State Department of Public Services
The most stringent code was the New York City Noise Code which required a daytime maximum of 61 dBA and a nighttime maximum of 47 dBA at the nearest sensitive receiver, a children’s playground. Without mitigation, the projected daytime and nighttime noise levels were 89 dBA and 119 dBA respectively.
The Astoria Energy project is also located near the Steinway piano factory, a boat club and a children’s playground so noise control was extremely important.
Project Challenges:
In addition to the stringent noise regulations, the project also had many logistical challenges. The site is surrounded by water on three sides and is so small that the wind wall had to be constructed from the inside (the space between the plant and the wall). Unions had to be coordinated and the project was on a tight time line.
Project Status:
ASL completed the project in the second quarter of 2011 after logging over 60,000 safe manhours. The post-construction noise levels have been tested to the satisfaction of the owner.