Applies to all data centers constructed in the unincorporated areas of Sebastian County, which must incorporate external noise-attenuation measures.

Before construction or operation, the owner and operator must notify all residents and homeowners’ associations within a half-mile radius, file proof of mailing with the County Clerk within 30 days, and notify the County Judge of the proposed location.

Before construction, the property owner must obtain a third-party acoustic-engineer baseline sound study measuring noise at eight property-line locations and file the report with the County Judge and County Clerk within 30 days of completion.

Before construction, the owner must consult a third-party architectural or design firm and prepare a building plan with adequate noise-attenuation measures, such as soundproofing, screens, fences, enclosures, or buffer yards.

Mechanical equipment must be shown on the proposed plan and fully screened on all sides; equipment not screened by the building facade must have a visually solid compatible fence, screen wall, panel, or parapet wall.

The building plan must be provided to the County Judge and filed with the County Clerk within 30 days after completion and before construction begins.

Any addition, change, or expansion of a data center must comply with the chapter’s noise-attenuation requirements and must be designed and submitted to the County Judge and County Clerk as required.

After construction, the operator must obtain a third-party acoustic-engineer study while mechanical equipment, including HVAC units and generators needed for peak operation, runs at full capacity; the study must use the original eight property-line locations and be filed within 30 days of completion.

A data center may not begin operations until the post-construction noise study is completed, submitted to the County Judge and County Clerk, and demonstrates compliance; noncompliant facilities must install required attenuation and meet the noise limits before operating.

The operator must conduct annual noise studies using the baseline and post-construction study specifications and provide the results to the County Judge and County Clerk within 30 days after the anniversary date of the first sound-study report.

Noise from a data center is prohibited at or above 65 dBa from 8:00 a.m. to 10:00 p.m. or at or above 55 dBa from 10:00 p.m. to 8:00 a.m., measured at the receiving property’s property line by a third-party acoustic engineer.

Noise measurements must follow specified procedures, including limits on outdoor testing during winds over 15 miles per hour or unsuitable wet or temperature conditions, immediate meter calibration, placement at least four feet above the ground or reflective surfaces, and high, average, and low readings or at least three measurements.

Failure to incorporate approved attenuation measures, file required studies or plans within the specified 30-day periods, meet the noise limits, or comply with another chapter requirement constitutes a violation, and a data center must be compliant before commencing operations.

Violations may result in an injunction or stay preventing commencement of operations, and a noncompliant operating data center must cease operations until required attenuation measures are implemented and the noise limits are met.

Violators may be guilty of a misdemeanor and, upon conviction, face a $1,000 fine per specified offense, double that amount for a repeat offense, and an additional $500 per day for a continuing violation.

A proposed data center’s building plan does not have to adopt all of the acoustic engineer’s noise-mitigation recommendations, provided the architectural or design firm determines that the selected measures are adequate for compliance with the chapter. The plan is not required to adopt any or all recommendations.