There are certain aspects of the internal environment that are up for debate. Are data center humidity levels that important?

Controlling the internal environment of a data center is always a top priority and heated discussion topic.

There is no doubt that maintaining the proper environmental conditions within a data center is vital because it affects energy consumption, infrastructure costs and the lifespan of equipment.

When it comes to controlling the internal environment of data centers, humidity has long been thought to be equally important as temperature.

In early 2012, ASHRAE expanded the recommended ranges for temperature and humidity within a data center environment. This immediately raises a question of how important controlling humidity levels really are.

Data Center Monitoring

Humidity is an element of the internal environment of data centers which must be present, but only in the proper proportion. Too much humidity quickly leads to condensation which causes corrosion, electrical malfunctions, and damages equipment.

On the other hand, too little humidity leads to a greater buildup of electrostatic charge. Once discharged, static electricity can damage or even destroy electronics throughout the facility. To combat this, most data centers install humidity sensors to provide information about internal environmental conditions.

How to Approach Humidity Monitoring in a Data Center

Traditionally, data centers use relative humidity to gauge humidity levels within a data center environment. The goal is to maintain a relative humidity reading of 45% to 55%. Unfortunately, this can be a difficult task to achieve because maintaining a standard level of relative humidity is completely dependent upon the internal temperature of the facility. This is because relative humidity is a measure of the percentage of water vapor the air can hold. As temperatures change, the amount of moisture the air can hold changes as well.

To complicate matters, data centers are forced to deal with both warm air and cool air in separate areas of the facility.

Cool air flows into the facility and is ejected as warm exhaust. Throughout this process, the water content of the air doesn’t change, but the relative humidity will.

Measuring Absolute Humidity

The alternative to relative humidity is measuring absolute humidity. Absolute humidity is the amount of water per unit of dry air. The term most people are familiar with in relation to absolute humidity is the dew point. The advantage of monitoring absolute humidity temperatures instead of relative humidity is that it is the same regardless of how warm or cool the air is. This allows data centers to have less of a moving target.

Humidity Monitoring and the Future of Data Centers?

With wider ASHRAE guidelines, data centers no longer need to place a great emphasis on humidity levels as when the 40%-55% rule was in place. While humidity monitoring will always be essential, companies and manufacturers have realized the tight limits on temperature and humidity are not as rigid as originally thought. As more data centers switch to absolute humidity, it will be easier not only to control humidity but to also determine the right temperature and humidity range for individual facilities.

About the author: Jon Kristoff, who has researched the data center industry for years, wrote this post on behalf of datafoundry. Jon wishes to inform readers of energy efficiencies so they can make the best educated decisions for their data center needs.