Relative humidity is the percentage of the total water vapor that can exist in the air without condensing, and is inversely proportional to air temperature. Humidity goes down when the temperature rises, and goes up when the temperature drops. For example, air with a relative humidity of 45 percent at a temperature of 24° Celsius (75° Fahrenheit) has a relative humidity of 65 percent at a temperature of 18° Celsius (64° Fahrenheit). As the temperature drops, the relative humidity rises to more than 65 percent, and water droplets are formed.
The ambient relative humidity range of 45 to 50 percent is suitable for safe data processing operations. Most computer equipment can operate in a wide range (20 to 80 percent), but the range of 45 to 50 percent is recommended for the following reasons:
Optimal range helps protect computer systems from corrosion problems associated with high humidity levels.
Optimal range provides the greatest operating time buffer in the event of air conditioner control failure.
This range helps to avoid failures or temporary malfunctions caused by intermittent interference from static discharges that may occur when relative humidity is too low.