Everything You Need to Know About Cleanroom Humidity Levels


Cleanrooms are critical workspaces, commonly used in industries such as pharmaceuticals, automotive and aerospace manufacturing, biotechnology, and more. Contamination and uncontrolled humidity are two of the significant concerns in these types of environments, which can ultimately impact and comprise the environment and contents within. In this blog post, we’ll take a closer look at the significance of humidity in cleanrooms and why it’s important to maintain specific humidity levels.

What is Relative Humidity for Cleanrooms?

Relative humidity is a measure of the amount of moisture in the air, compared to the amount of moisture required for saturation at a specific temperature. The ideal range of relative humidity for a cleanroom varies from 30% to 40%. In certain environments, ideal levels can be slightly higher or lower.

Impact of Poor Humidity Control

If the relative humidity falls below the ideal range, the environment becomes dry, and static electricity could build up, leading to machinery failure or irreparable damage to components. Alternatively, humidity level rising above ideal levels can cause condensation, resulting in the formation of bacteria and mold, degradation, and corrosion. This can lead to contaminated products or materials being handled in the cleanroom.

Additionally, high humidity levels can cause solvents to evaporate and condense moisture, compromising process control and quality. In pharmaceutical settings, excessive humidity can result in clogs in tablet dies due to inconsistent powder.

Why is it Important to Regulate Humidity in Cleanrooms?

Regulating humidity is critical in cleanroom applications as it ensures that the surrounding atmosphere provides enough moisture to materials and components while simultaneously protecting them from static discharge and moisture damage. Additionally, differing work processes require different humidity levels to improve production quality. Electrical equipment performs better when the humidity in the air around it is slightly elevated, while pharmaceuticals require a lower humidity percentage to keep the drugs stable and potent.

Relative Humidity Monitoring

Monitoring the relative humidity in your cleanroom is essential to ensure that the perfect conditions are being maintained. To accurately measure relative humidity, hygrometers are typically used. These devices come in a wide range of shapes and sizes, from handheld devices to those that are built directly into monitoring systems.

Humidity Control Options

The humidity control method used depends on the individual facility’s needs and the intended application, ranging from simple evaporative humidifiers to more complex systems with multiple sensors and controls. In some cases, the preferred option is a thermo-electric dehumidifier, which can reduce the humidity content in the air without needing an external water supply. Additionally, desiccant solutions, including molecules like silica gel, can absorb moisture from the surroundings to maintain continuous low humidity.


Maintaining cleanroom humidity levels can be challenging, but the right understanding of how relative humidity behaves, what must be maintained, and the best methods to accomplish it will ensure your products and components are kept in top condition. The best way to determine if your cleanroom environment is set up correctly is to have regular testing performed to verify that your relative humidity levels are precise. A consistent examination will significantly reduce the chance of unexpected changes to the air quality, which is critical in highly controlled environments like cleanrooms.


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