Why Do Cleanroom Temperature and Humidity Matter
An effective cleanroom controls the amount of particulate matter in the air according to specification, but cleanrooms often operate under strict temperature and humidity conditions as well. Why do cleanroom temperature and humidity matter? There are three main reasons: controlling the shedding of skin cells and other biomatter, controlling static, and ensuring the comfort of cleanroom personnel.
Controlling Cleanroom Temperature and Humidity
From a contamination point of view, the primary reason to control temperature and humidity within the cleanroom environment is that the people working in the cleanroom introduce the most contamination to the room. They don’t introduce contamination solely when they enter or exit the room. Just by breathing, sweating, and shedding skin cells, they add to the work that the room’s filters must do to keep it clean.
The greater the number of people in the cleanroom, the more skin they shed. Too high or too low temperatures can also increase shedding beyond what gowning can contain. Human skin regenerates continuously. Over a 24-hour period, an adult will typically shed nearly a million skin cells. If the room is too dry, workers’ skin will also be drier, and they may shed more skin cells. If the room is both too hot and too dry, this effect will be magnified. Dry air can cause an increase in respiratory ailments, and staff absences, over time as well. If the room is too humid, microorganisms have a better chance of thriving, and metal is more likely to corrode.
Heat affects how much people sweat, which can affect how well their gowns work as well. If they sweat through their gowns or cleanroom suits, the containment capacity of clothing or masks will be impaired. If they shiver because the temperature is too low, this also impairs the effectiveness of their protective clothing. Workers may slow down because they are too hot, or speed up trying to get warmer. These patterns affect the airflow of the room and impede its design and functionality.
A second reason to carefully control temperature and humidity is that static electricity may cause particles to be pulled to the surfaces within the room. They can also be drawn to workers’ gloves. Dry air produces more static electricity. Adjusting the humidity can help lower static and the risk of contamination.
Optimizing Worker Comfort
Finally, when the temperature or humidity are not optimal, it affects the overall comfort of staff. When staff members are comfortable working, they are happier and more productive. Typically, the temperature of a cleanroom is lower than the temperature in an office building. This is partly due to the higher activity level of workers within the room and also the fact that they wear protective clothing which can feel uncomfortable in higher temperatures.
Organizations need to take into account all of the above factors when they install their cleanrooms. A well designed and carefully maintained HVAC system that controls both cleanroom temperature and humidity can be a crucial part of cleanroom design and should not be overlooked.