Importance of humidity testing in cleanrooms

A CleanRoom is a manufacturing environment with low levels of environmental contaminants such as dust, airborne microorganisms, aerosol particles, and chemical vapors. The air inside is constantly recirculated through high-efficiency particulate air (HEPA) filters. Some cleanrooms are entire manufacturing facilities and can cover thousands of square meters. Cleanrooms are classified according to the number and size of particles allowed per unit of air. Today, ISO 14644-1 is the official metric, which specifies the number of particles (0.1 µm or larger) allowed per cubic meter of air.

Problems caused by temperature and humidity deviations

Cleanroom Testing stipulates many different parameters. Cleanrooms are widely used by Semiconductor Manufacturers. Today, more and more biotechnology, life sciences and other fields that are sensitive to environmental contamination also use cleanrooms. Cleanrooms are used in a variety of industries: pharmaceutical, semiconductor, aerospace, food, laser and optical...

The effects caused by humidity can be expansion, contraction, hardening and softening of materials, viscosity changes of liquids, growth of microorganisms, increased static electricity, corrosion and rust.

All applications have different temperature and humidity specifications. Abnormal levels of these parameters can have a significant impact on product quality and production efficiency (and can even lead to production losses).

High humidity and/or temperature can cause some instruments to fail.

Low humidity can generate static electricity, which can ruin production batches as well as expensive measuring equipment.

Importance of controlling humidity

Pharmaceutical manufacturers control and record temperature and humidity in accordance with GMP and internal quality guidelines.

Semiconductor and Electronics manufacturing processes require different precise controls in their cleanrooms.

In the food industry, it is important that relative humidity is kept below 40%: this limits the growth of bacteria and germs.

The better the environment is controlled, the smaller the deviations in product quality. The result will be smaller deviations in bioassays, smaller deviations in integrated circuit manufacturing and food production, and smaller growth of microorganisms. 

Accurate humidity measurement directly affects the energy consumption of the cleanroom. The sooner any power-consuming equipment is turned off, the less power is consumed.

Related solutions

One thing to note about Cleanroom temperature and humidity control is to specify them to tolerances that are too low or too tight. This in turn translates into construction costs and operating costs of the cleanroom.

For example, humidity is relative - relative to humidity. If you set the temperature at 70 degrees and 50% Relative humidity, setting the temperature at 68 degrees would be 55% relative humidity. So that 2 degree difference translates into having to dry the air to get its moisture content down, and that costs a lot of money.

When you try to Control humidity to very tight tolerances, you have to push the chilled water down to pull moisture from the environment. Usually, this translates into a bigger chiller because if you try to get it down too low, you have to do what's called "turning the chiller down." What that means is you have to put glycol in that system to allow that system to flow water at a lower temperature or get the water closer to freezing. So when you add glycol to it, that chiller has the ability to transfer heat, and it reduces that ability.