As data center construction faces more community opposition, one lesser-known complaint is gaining attention: infrasound, the low-frequency acoustic energy below 20 Hz that most people can’t consciously hear but may perceive as pressure changes, vibration, or rattling in nearby structures.
Where It Comes From
Infrasound has natural sources too, including ocean waves, storms, and seismic activity, but several data center systems can also generate it. Cooling towers and large axial fans can emit low-frequency sound that travels well beyond the site boundary, particularly under certain wind or atmospheric conditions. Standby generators, through their engines, exhaust systems, and enclosures, are common contributors, especially during testing or outages. Server fans mainly produce mid- to high-frequency noise but can add to low-frequency hum in aggregate through airflow paths and structural resonance, though they’re typically secondary compared to cooling plants and generators.
Why It’s Becoming a Bigger Issue
Most local noise ordinances address only audible sound, and infrasound is difficult to measure without specialized equipment. Few communities have conducted the assessments needed to confirm high infrasound levels, let alone tie them conclusively to a specific data center or to health effects. Still, residents near facilities have reported headaches, nausea, anxiety, and other symptoms they attribute to low-frequency noise, and these complaints are increasingly shaping local debates and regulatory scrutiny, even though most claims haven’t been fully validated.
Mitigation Strategies
Operators have several practical, relatively low-cost options to reduce infrasound emissions:
- Regular maintenance: Clean fans and heat exchange surfaces to keep equipment running smoothly and reduce low-frequency generation.
- Larger, slower fans: Bigger-diameter fans running at lower RPM can produce less low-frequency energy than smaller, faster ones for the same airflow.
- Vibration isolation: Anti-vibration pads and proper mounts decouple noisy equipment from floors and walls, since low-frequency energy travels efficiently through solid structures.
- Tuned enclosures and silencers: Properly sealed enclosures around generators and large fans cut low-frequency output during operation and testing.
- Reduced generator runtime: Relying on the grid for normal operations, scheduling tests in daytime windows, and using battery energy storage all limit generator-driven noise.
- Active noise control: Useful in narrow, controlled scenarios but rarely practical at facility scale or in open-air settings.
- Liquid cooling: Reduces reliance on high airflow and fan noise, though pumps need proper isolation to avoid introducing new low-frequency transmission paths.
Transparency Matters
Beyond engineering fixes, operators are encouraged to measure infrasound levels and communicate openly with communities about findings and mitigation steps, rather than dismissing concerns as purely perceptual. That kind of transparency is likely to matter as much as the technical fixes themselves in maintaining good relationships with neighbors, politicians, and regulators.