Controlling the humidity in your cleanroom is crucial, not only to meet government and company specifications, but to protect the integrity of your processes and product. If the humidity is too high, bacterial growth can flourish, metal products or equipment can corrode, photolithographic degradation can occur, and condensation and water absorption can occur. If the humidity is too low, static buildup and discharge can become an issue. Plus, poorly controlled humidity can make working conditions uncomfortable for your employees. What are some of the methods you can use to control humidity in your cleanroom?
Air conditioning/mechanical refrigeration
Humidity is relative, meaning that the lower the temperature is, the lower the relative humidity is. It makes sense then if you lower the temperature in the space, the humidity will decrease. When using air conditioning systems to dehumidify a space, the system lowers the temperature of a surface to a temperature below the dew point of the airstream in the cleanroom. The surface is exposed to the airstream in the cleanroom, and the water vapor in the airstream condenses, subsequently dehumidifying the space. To maintain the desired room temperature, the air must be re-heated and piped back into the cleanroom.
Desiccant systems draw air through a desiccant medium, which adsorbs moisture. The dehumidified air is then routed to the cleanroom. Unlike consumer-grade desiccant systems, which collect condensate in a receptacle that must be emptied (if you’ve ever had a dehumidifier in your home, say in a finished basement, which can trap moisture, you’ll recall having to empty the condensed water), commercial systems exhaust humid air through the ductwork, out of the building. This allows for greater dehumidifying power and the ability to dehumidify to lower relative humidity levels at lower temperatures.
These systems are not mutually exclusive, in fact, both work best when used in conjunction, especially where temperature control is also important, as in a cleanroom. Using a desiccant system in addition to air conditioning can also help reduce the load on the HVAC system, saving energy, wear and tear on the HVAC system, and, of course, money.
Humidity control is absolutely critical in some cleanroom applications, such as semiconductor manufacturing and pharmaceutical manufacturing, but it is an important consideration no matter your application. Monitoring and controlling your cleanroom humidity, whether through air conditioning/mechanical refrigeration, a desiccant system, or both, is necessary to meet your cleanroom’s specifications and to ensure cleanroom integrity.
No matter your application, Angstrom can design a cleanroom to meet your cleanroom needs. Contact us to discuss your cleanroom project.