Set Permissible Noise Levels

Set the lowest possible threshold for continuous noise. The ordinance currently with the lowest thresholds, from Divide County, North Dakota, establishes that the maximum continuous sound levels for data centers cannot exceed 50 dBA during the daytime and 45 dBA at night. These thresholds should include low-frequency noise levels and noise coming from ancillary data center usage (such as emergency diesel generators and construction). Thresholds may vary depending on zoning (for example, if a data center abuts a residential zone).

Note: The National Institute for Occupational Safety and Health (NIOSH) threshold for requiring hearing protection is 85 dbA over eight hours. Noise around data centers can reach up to 92 dBa.

Strong example

Divide County, North Dakota, establishes the maximum continuous sound level for data centers during the daytime as 50 dBA, and 45 dBA at night.

Strong Example

Marana, Arizona, stipulates that maximum sound levels for data centers cannot exceed 55 dBA in residential and mixed-use properties during both daytime and nighttime.

Example

Phoenix, Arizona, and McPherson County, South Dakota, stipulate that noise levels cannot exceed 55 dBA during the day and 45 dBA from 10 p.m. to 7 a.m. for data centers abutting residential zones.

Weak Example

Coweta County, Georgia, stipulates that noise levels for data centers cannot exceed 5 dBA above ambient from 10 p.m. to 7 a.m., or 10 dBA above ambient from 7 a.m. to 10 p.m. Per the ordinance, the county will conduct an ambient noise survey. This strategy creates the risk that minimum thresholds could be set higher than recommended.