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Home My WebLink AboutCity Council Minutes 2026 07-14-26 Soundscape Engineering 3711 N. Ravenswood Ave., Ste. 104 • Chicago, IL 60613 • (312) 436-0032 729 W. Ann Arbor Trl., Ste. 150 • Plymouth, MI 48170 • (734) 418-8663 www.SoundscapeEngineering.com July 914, 2026 Ms. Krysti J. Barksdale-Noble, AICP Community Development Director (630) 553-8573 T (630) 742-7808 M knoble@yorkville.il.us United City of Yorkville 651 Prairie Pointe Drive Yorkville, IL 60560 Subject: CyrusOne CHI 11, Yorkville, Illinois Recommended Guidelines for Data Center Noise Impact Studies Submitted with Permit Applications – Rev. 1 Dear Krysti: Soundscape Engineering has been asked to provide guidelines for the CyrusOne CHI 11 data center noise impact study to be submitted with the permit application. Based on our professional experience in the field of environmental noise impact, we offer the following list of elements for your consideration. 1.0 Background C1 Yorkville LLC, a wholly owned subsidiary of CyrusOne, is seeking approval from the United City of Yorkville for the development of CHI 11, a 228-acre data center campus and on-site substation development. The original PUD was approved on July 9, 2024, and C1 Yorkville has submitted a major change to the PUD, including an updated initial sound study dated April 22, 2026. The project is also required to submit a final noise study before permitting approval. The City requested that Soundscape Engineering provide a list of recommended requirements for noise impact studies to guide this final noise study submission. 2.0 Recommended Data Center Noise Impact Study Elements A comprehensive data center noise impact study is recommended to include the following elements: 1. Executive Summary a. Concise overview of the report and its findings, including description of the proposed facility, planned equipment and operating modes, predicted ordinance compliance status, and planned mitigation measures. Noise Impact Assessment Guidelines Rev. 1 – Cyrus One July 914, 2026 SE No. 2234 Page 2 of 5 Soundscape Engineering 3711 N. Ravenswood Ave., Ste. 104 • Chicago, IL 60613 • (312) 436-0032 729 W. Ann Arbor Trl., Ste. 150 • Plymouth, MI 48170 • (734) 418-8663 www.SoundscapeEngineering.com 2. Preparer Credentials a. Name, professional qualifications, and credentials of the acoustical consultant(s) who performed the work (INCE Board Certification or NCAC membership strongly preferred). 3. Acoustic Terminology a. Definitions or descriptions of the acoustic terminology used in the report in order to allow readers, who are typically not well-versed in the field of acoustics, to better understand the information conveyed in the report. 4. Project Description and Source Inventory a. Detailed description of the proposed facility (IT load, phasing, building heights, and mechanical equipment locations). b. Proposed site plan drawn to scale and clearly indicating the boundary road names, jurisdiction, and zoning of properties surrounding the development c. Complete inventory of all significant noise sources, including: i. Make, model, quantity, and operating conditions for each piece of noise- producing equipment, including transformers/substations associated with the project, even if not owned by the project. ii. Sound power levels (Lw) — measured data at the planned operating points, not calculated or derived from other equipment, when available. Worst-case manufacturer data may also be used when measured data is unavailable. iii. Octave-band sound power level data for all noise-producing equipment, and source of the Lw data. iv. Location and elevation of equipment and a description of how it was modeled (point source, area source, or combination) d. Description of all operating scenarios to be modeled, including, but not limited to: i. Routine/normal operations (day and night) ii. Reasonable worst-case conditions (e.g., hot/humid day with maximum cooling load) iii. Include routine generator testing and indicate whether generator maintenance will be limited to daytime hours. Indicate duration and how frequently this is expected to occur. iv. Include utility outage scenario for informational purposes. iv. Construction phase noise (optional but recommended for information, particularly for projects that will be constructed in phases over a long period of time and will therefore result in long duration, ongoing construction activities) Formatted: Space Before: 12 pt, After: 12 pt Noise Impact Assessment Guidelines Rev. 1 – Cyrus One July 914, 2026 SE No. 2234 Page 3 of 5 Soundscape Engineering 3711 N. Ravenswood Ave., Ste. 104 • Chicago, IL 60613 • (312) 436-0032 729 W. Ann Arbor Trl., Ste. 150 • Plymouth, MI 48170 • (734) 418-8663 www.SoundscapeEngineering.com v.e. Provide a narrative describing anticipated sources of construction noise, an anticipated timeline of construction, and how construction activities will comply with noise regulations. e.f. Description and images showing the noise control devices, noise barriers, operational restrictions, or other noise control strategies that will be employed. i. Locations, dimensions, and elevations of any proposed berms/barriers ii. Quantified benefit, including octave band attenuation, for any louvers, silencers, enclosures, mufflers, and other noise control devices 5. Regulatory Framework and Assessment Criteria a. Reference to all applicable noise performance standards or ordinances, including state regulations b. Criteria used for assessing noise impact, including any consideration of ambient, tonality, and low-frequency noise that were employed. 6. Existing Ambient Noise Conditions (Optional, but Recommended) a. This is recommended in addition to the baseline noise survey conducted with the initial noise study, especially if the soundscape has significantly changed since the baseline survey, such as new development near the proposed development. b. Detailed ambient noise measurements at representative sensitive receiver locations (residential properties in all directions, schools, parks, etc.). i. Measurement locations should represent the locations of greatest impact on residential properties, where site access allows. ii. Consider areas further from roadways and other noise sources. iii. Provide the measurement locations for review prior to making the measurements. c. Survey duration: Minimum 72 hours, including at least one weekend (when ambient levels are typically lowest). d. Documentation must include: meter and microphone Class, make, model, serial numbers, and calibration dates. e. Metrics: At each measurement location, LA,eq(hr) and LA,90(hr) for survey duration, and unweighted Leq octave band levels during the quietest nighttime and quietest daytime hour. Provide this information in table and graphical format. f. Weather conditions and measurement locations must be clearly documented. Formatted Noise Impact Assessment Guidelines Rev. 1 – Cyrus One July 914, 2026 SE No. 2234 Page 4 of 5 Soundscape Engineering 3711 N. Ravenswood Ave., Ste. 104 • Chicago, IL 60613 • (312) 436-0032 729 W. Ann Arbor Trl., Ste. 150 • Plymouth, MI 48170 • (734) 418-8663 www.SoundscapeEngineering.com 7. Noise Prediction Methodology a. Use of three-dimensional sound propagation modeling software based on ISO 9613-2 (e.g., CadnaA or SoundPLAN), including all the topography, acoustically relevant buildings, sources, receivers, and evaluated mitigation measures. b. The analysis area should extend at least one mile from the property boundary in each cardinal direction. It is not necessary for the computer model to include all structures beyond the project site. c. All modeling parameters and settings must be clearly stated, including: i. Source directivity ii. Ground absorption factors iii. Temperature, humidity, and wind conditions iv. Terrain and topography v. Reflections vi. Grid spacing vii. Receiver/grid height viii. Coordinate Reference System (CRS) d. Any changes made to the design after approval must be analyzed and resubmitted. 8. Modeling Results For each scenario in the study, provide: a. Tables of predicted noise levels at discrete receiver locations: i. Overall, and octave band , and third-octave band data, as required for assessment per the criteria, including tonality ii. Assess multiple grade elevations, if necessary, to evaluate impacts iii. Include UTM coordinates and addresses iv. Include 26 locations identified for cumulative analysis b. Contour maps of each operating scenario showing: i. Clearly labeled or distinguishable sound level contours ii. Results with and without mitigations iii. Both close-up views of the nearest receivers and broader contextual views of the surrounding area for key scenarios 9. Impact Evaluation a. Demonstration of compliance through comparison of predicted levels to criteria. Noise Impact Assessment Guidelines Rev. 1 – Cyrus One July 914, 2026 SE No. 2234 Page 5 of 5 Soundscape Engineering 3711 N. Ravenswood Ave., Ste. 104 • Chicago, IL 60613 • (312) 436-0032 729 W. Ann Arbor Trl., Ste. 150 • Plymouth, MI 48170 • (734) 418-8663 www.SoundscapeEngineering.com a.b. Assessment of tonality, including through use of third-octave band source data (if published) 10. Appendices a. Detailed information, including source data, receiver data tables, and contour maps, may be included in the appendices as appropriate. 3.0 Conclusion This list of elements is not exhaustive; in In all areas, sufficient detail should be provided such that an independent acoustic professional can reproduce the sound propagation calculations at discrete points to check both the methodology and the results. For major noise-producing equipment types that are predicted to be dominant noise sources, the project should specify equipment sound power levels in the project bid documents and require that the manufacturer measure equipment sound levels for a sample unit before delivering to the site. Sincerely, Soundscape Engineering Per: Nathan Sevener, INCE Bd. Cert. Principal Consultant nsevener@SoundscapeEngineering.com direct: (734) 669-3260 Aimee Lalime, INCE Bd. Cert. Senior Consultant alalime@SoundscapeEngineering.com direct: (703) 462-5825