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According to the "source control and categorized management" principle of the "Noise Pollution Prevention and Control Law," enterprises bear primary responsibility for cooling tower noise pollution. GB 12348-2008 (2025 Edition) specifies daytime limits of 55dB(A)/nighttime limits of 45dB(A) for Category 1 (residential) areas, and higher limits for Category 4 (traffic arterials). Exceeding these limits will result in regulatory penalties. Cooling tower noise control combines the dual benefits of "green production compliance" and "building harmonious communities." The following article systematically analyzes the causes of noise and provides comprehensive control solutions.
Causes of cooling tower noise
Cooling tower noise mainly comes from fan noise , including aerodynamic noise (proportional to the sixth power of the rotational speed) and mechanical vibration noise; the second is water flow noise . Water droplets hitting the water collection tank produce 70-80dB(A) high-frequency sound, the intensity of which is related to the height of the falling water and the flow rate.
Different types of cooling towers have different noise characteristics due to differences in structural design:
Comprehensive governance technical solutions
Adopting a three-level governance system of "source-dissemination-end":
Source control: low-noise fan (wing-shaped blades reduce noise by 5-10dB) + variable frequency speed regulation (40% speed reduction at night)
Propagation blocking: Impedance composite silencer (noise reduction ≥ 25dB(A)) + sound insulation barrier
Terminal optimization: honeycomb cushion (noise reduction of 15dB when falling into water) + inclined PVC filler (speed reduction of 30%)
Regulatory standards and compliance requirements
Cooling tower noise control must strictly adhere to national and local regulations and standards. At the national level, GB 12348-2008 (2025 Edition), the "Emission Standard for Environmental Noise at Industrial Enterprise Boundaries," specifies limits for acoustic environment functional zones 1-4. For Category 1 (residential areas), the daytime limit is 55dB(A)/nighttime limit is 45dB(A) , while for Category 4 (traffic arterials), the daytime limit is 70dB(A)/nighttime limit is 55dB(A). Nighttime limits are generally 10dB stricter than daytime limits.
Under special operating conditions, frequent nighttime noise (≥4 times/hour) must be reduced by an additional 5dB from the limit, and sudden noise peaks must not exceed the limit by 15dB. According to the Noise Pollution Prevention and Control Law, businesses exceeding noise emission standards will face fines of 200,000 to 2 million yuan. Sensitive areas must also implement special period filing and public disclosure. In Category 1 areas, exceeding the nighttime standard by 5dB triggers rectification, while peaks exceeding 15dB are directly considered illegal. Businesses must establish systematic noise control systems to mitigate risks.
Maintenance and management recommendations
Implement full-cycle management and control of "quarterly maintenance + water quality management + intelligent regulation":
Quarterly maintenance: fan blade dust removal, bearing No. 3 lithium grease lubrication, water distribution system inspection
Water quality management: monthly pH monitoring, semi-annual filler cleaning
Intelligent adjustment: Water temperature threshold triggers linkage control to reduce the speed by 20%
The industry needs to continue to take technological innovation as the foundation, management optimization as the focus, and policy standards as the guide, and ultimately achieve the social responsibility goal of "quiet production and harmonious coexistence".