Environmental Chambers - Elevated Humidity Applications

Environmental Chamber with stainless steel
construction for elevated humidity applications.
Courtesy Powers Scientific

There are many testing, research, and production applications that require environmental moisture control at elevated levels. Environmental chamber manufacturers provide a broad offering of products, some tailored to very specific test or process requirements, others which will accommodate a wider range of operating conditions.

The challenge of product selection for a particular use can prove challenging for those not familiar with operational aspects of the equipment and systems that comprise an environmental chamber with humidity control. Selections of humidification equipment or cooling system, in particular, can have a real impact on chamber performance and maintenance requirements.

The stated performance for any environmental chamber is based upon a range of ambient conditions surrounding the chamber or its equipment. Every chamber will not necessarily work properly in every setting. It is important to consult with the manufacturer to make sure the intended use and location of the equipment is within its design range. For any unit under consideration for use, its ability to deliver needed performance levels depends, in large part, on the manufacturer's knowledge of how the chamber will be used and where it will be installed.

Generally, equipment manufacturers design environmental chambers to perform at the published design conditions when properly installed in most commercial or institutional buildings. To assure successful operation, a prospective user should consult with the chamber manufacturer's application specialists to verify there is a match between the user expectations and the equipment suitability for the project. Here are some things to consider.

• Define the chamber conditions to be maintained. For humidity control applications, it is important for the manufacturer to know the specific combinations of temperature and humidity setpoints that will be used. For example, 80% RH (relative humidity) at +32°C. This helps the manufacturer to confirm overall chamber performance will meet user needs and verify that any options selected are compatible with the desired operating conditions.
• Establish the range of environmental conditions that exist at the exact installation site - A humidified chamber generally has capacity to add moisture, but not remove it. Confirming the range of temperature and relative humidity conditions that can be present throughout the year helps assure that environmental chamber performance will not be adversely impacted by the surrounding air conditions.
• Know where the heat will go - Cooling systems transfer heat from inside the chamber to outside the chamber. A unit with a cooling system of the self-contained air cooled type will reject all heat removed from the chamber, plus some extra generated by the cooling machinery, to the space surrounding the chamber. While the amount may be small, without an adequate means of removing that heat from the installation area, the temperature surrounding the chamber will rise. This is especially important when contemplating the placement of an environmental chamber within a small room with little ventilation.
• Know what is happening in the chamber - Are you adding heat with an apparatus or piece of equipment placed in the chamber? Are materials being added to the chamber that may be at moisture or temperature conditions that differ from the chamber setpoint? These and other user associated loads can impact chamber performance.

Time invested prior to purchase and installation to match the chamber capability with project environmental requirements will pay dividends for the life of the unit. Share your project requirements with an environmental chamber specialist, combining your own knowledge and experience with their product application expertise to develop an effective solution.