Sound
The building does not sleep.
dBA is a weighted decibel. Roughly: a 10 dB drop feels about half as loud. Distance helps. Barriers help. A monthly generator test is a different animal from the 3 a.m. fan wall.
Most ordinances use dBA, which down-weights low-frequency energy. A data-center fan wall and transformer hum live in that bass. A facility can be legal on dBA and still be a sleep problem. dBC (or a third-octave study) is a different instrument. This slider is still dBA, at an example distance, not a San Antonio meter.
Hall / condenser fans
54 dBA
Continuous. The 24/7 problem is usually this, not the generator.
Cooling towers
60 dBA
Example at tens of feet from equipment, not the property line.
Dry coolers
58 dBA
Walls of fans. Liquid halls can be quieter than air halls. Still not silent.
Transformers
37 dBA
Low-frequency hum. Often felt more than heard.
Generators
—
Quiet until a test or an outage. Then they are the loudest thing on the site.
Construction
67 dBA
Temporary. Months to a few years. Not the operating soundscape.
Simple spherical spreading from a 50 ft reference. Real sites use ISO 9613-2, barriers, and night inversions. Property-line limits in many U.S. jurisdictions sit near 45–55 dBA. Setbacks beat mufflers.
Data last checked 2026-09-04 · Current public data is a snapshot, not a live meter
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