Acoustic Design for Cleanrooms: Achieving Both Silence and Purity

Introduction

When we think of a cleanroom, we tend to focus on air cleanliness—particle counts, pressure balance, and filtration.
However, acoustic conditions such as noise, reflection, and reverberation also have a significant effect on work quality and concentration.

This article explains why acoustic design matters in cleanroom environments and how to create spaces that maintain both hygiene and quietness using modern sound-absorbing materials.

Why Acoustic Design Matters in Cleanrooms

Traditional cleanroom design emphasizes temperature, humidity, airflow, and cleanliness class.
Yet, noise and reverberation often go overlooked despite their direct impact on productivity and measurement accuracy.

Common noise sources include:

• Airflow noise from HEPA filters and fan units
• Impact noise from shutters and doors
• Reflection and echo from hard, flat wall and ceiling surfaces

These factors can cause fatigue, communication errors, and even process deviations.
In other words, just as we pursue air purity, we must also ensure “acoustic purity.”

Identifying Noise Sources: The First Step in Acoustic Design

The first step toward a quiet cleanroom is to identify and classify the sources of noise.

Cleanrooms are typically constructed from hard, non-porous panels.
As a result, even moderate noise reflects multiple times, creating a harsh, echoing sound field.
Without acoustic absorption, the perceived noise level can remain high despite low actual decibel values.

Key Requirements for Cleanroom-Compatible Absorbers

Conventional materials such as glass wool or foam are unsuitable for cleanrooms because of particle shedding, water absorption, or chemical degradation.
Sound-absorbing materials must meet the following requirements:

• Non-fibrous structure (no particle emission)
• Washable, non-absorbent surface
• Low VOC and chemical resistance
• Non-combustible rating available
• High absorption in mid- to high-frequency range

Acoustic Design Principles for Cleanrooms

Acoustic design is not just about selecting the right material—it requires coordination with layout and airflow design.
The following three points are particularly important:

(1) Balanced Absorber Placement

Install absorptive panels on ceiling and upper wall areas where reflections are strongest.
This reduces overall reverberation without affecting cleanability.

(2) Combination of Absorption and Insulation

Use composite wall structures that combine sound insulation (for separation) and absorption (for reflection control) to achieve both quietness and isolation.

(3) Compatibility with Airflow

Ensure absorber placement does not disrupt laminar airflow.
BFB panels can be designed for both acoustic and airflow stability while maintaining easy cleaning.

Case Study: Quieting an Electronic Component Cleanroom

Background

A production area suffered from constant fan noise of approximately 80 dB(A), with poor voice intelligibility due to metal wall reflections.

Solution

• Installed BFB panels on ceiling beams and selective wall sections
• Added sound-absorbing ducts on supply air lines
• Used removable mounting brackets to allow regular cleaning

Results

• Noise level reduced from 80 dB to 72 dB
• Noticeable reduction in reverberation and fatigue complaints
• Passed hygiene inspection with no impact on cleanliness

Conclusion: Silence as a Dimension of Cleanliness

In a modern cleanroom, acoustic comfort is a component of quality control.
A quiet environment enables higher precision, fewer errors, and improved operator well-being.
Designing for silence is, ultimately, designing for cleanliness and reliability.
Future cleanrooms will be evaluated not only by air purity but also by how quietly they perform.