Quiet power: Why fan noise matters in sensitive environments

Industrial and HVAC fans do critical work—but they don’t need to shout about it. Excessive fan noise isn’t just annoying; it can violate noise regulations—especially in environments like offices, schools, clinics, and agri-processing facilities.

How loud is too loud for fan noise?

Research shows that noise levels above 55 dB(A) can start to impair focus, and levels exceeding 65–70 dB(A) can cause measurable drops in task performance. For context:

• 50 dB(A) = Refrigerator

• 60 dB(A) = Electric toothbrush

• 70 dB(A) = Loud vacuum cleaner

In HVAC systems, airflow noise, fan blade turbulence, and mechanical vibration can easily exceed these levels if left unchecked.

Regulations in South Africa

Many South African municipalities, including Johannesburg and Cape Town, follow SANS 10103 and local by-laws that specify:

• 55 dB(A) max for daytime (06:00–22:00)

• 45 dB(A) max for night (22:00–06:00)

In sensitive spaces like hospitals, schools, and offices, fan noise may need to stay within 3 dB of background noise, as guided by CSIR acoustic design recommendations. This means that if the background noise is 35 dB, such as in a library, the HVAC system cannot exceed 38 dB. 

Non-compliance can result in complaints, penalties, and even forced shutdowns during inspections.

What you can do to reduce noise

The blade pitch and rotation speed of your fan system should be optimised to meet both airflow and acoustic goals. A good partner will also balance all the moving parts of the system to prevent vibration-related noise. You can also add silencers, attenuators, or duct lining where needed in your HVAC system to further reduce noise.

Silence is a design choice. If you’re working in a noise-sensitive environment, make sure your fan system performs quietly—and within legal limits.