Experts tell Palm Beach County commissioners data‑center noise models fall within existing limits; board presses for low‑frequency standards and measurement

Acoustical and public‑health experts told the Palm Beach County Board of County Commissioners that predicted sound from the proposed Project Tango data center would be within county limits and similar to existing ambient noise near Arden and a nearby school.

Mark Bastash, an acoustical specialist brought by the applicant, said the project’s ISO 9613‑2 modeling shows about 45 dBA at the western edge of Arden and that predicted levels "are less than allowed by the county code" and fall within the range of existing measurements. Bastash also identified nearby sound sources — a 3,800‑megawatt combined‑cycle power plant, a six‑lane roadway, an asphalt plant and aggregate processing facilities — that dominate the local soundscape.

Dr. Norm Bridal, an acoustic consultant, told the board the modeling and additional analysis of C‑weighted (low‑frequency) levels support his conclusion that the data center’s contribution would generally not be particularly perceptible to nearby residents or the school. "In terms of level, it won't be particularly perceptible," Bridal said, describing the modeling as conservative because it assumes downwind propagation.

Dr. Chris Olson, a public‑health expert, said the modeling used worst‑case wind assumptions and reported a predicted DBC of about 56 at the school while daytime average ambient there is roughly 68. "The kids right now are out there playing ... they're not being impacted by those levels," Olson said, adding that levels associated with direct health harm on the DBC scale are far higher than those predicted for this project.

Commissioners pressed experts on low‑frequency criteria and enforceable thresholds. Commissioner Weiss asked what DBC value the county should use; Bridal said his published recommendation is roughly 70–75 DBC for daytime and about 65 DBC for nighttime, and he noted that some jurisdictions have discussed 50–55 DBC 24/7 but that a 55 DBC daytime limit is often impractical given typical ambient levels. County code currently regulates A‑weighted levels (dBA), with participants citing a daytime limit of 65 dBA and a lower overnight limit (55 dBA) in the code discussion.

Board members also asked whether the predicted low‑frequency "hum" seen in some complaints about other data centers would occur here and whether the project team could provide a recording or live replication. Experts said exact replication in the hearing room is not feasible, but they offered measured points of comparison. At the board’s request, Bastash used a calibrated ANSI Type 1 Larson Davis sound level meter to take a 10‑second measurement in the chamber and read 43.9 dBA and 59.8 dBC as an on‑record example.

The applicant representative said the development team has proposed conditions requiring pre‑operation and post‑operation measurements of both A‑ and C‑weighted levels so staff and retained experts can verify compliance once the facility is built. The applicant said FPL has an approved tariff related to the site that will protect ratepayers from unforeseen electricity‑cost impacts.

No vote occurred during the presentation. The board recessed for lunch and said it would reconvene at 1:15 p.m. for a staff presentation and further consideration of conditions.

The experts and applicant materials (including an acoustical modeling report and a public‑health review submitted to the county) are part of the meeting record; commissioners indicated they may seek additional measured examples and clarified noise‑condition language in the meeting packet (AD delete, C1b) before taking final action.