The server ambient relative humidity range of 45 to 50 percent is acceptable for safe data processing operations. An ambient relative humidity optimal range of 45 to 50 percent can:
Help protect computer systems from corrosion problems associated with high humidity levels.
Provide the greatest operating time buffer in the event of air conditioner control failure.
Help to avoid failures or temporary malfunctions caused by intermittent interference from static discharges that might occur when relative humidity is too low. Electrostatic discharge (ESD) is easily generated and not easily dissipated in areas where the relative humidity level is below 35 percent. ESD risk becomes critical when levels drop below 30 percent.
Most computer equipment can operate in a wide range (20 to 80 percent), but 45 to 50 percent is the recommended optimal range for the reasons listed.