Recommended Temperatures And Humidities For Computer Rooms - Fujitsu M10 Series Installation Planning Manual

4.3.2 Recommended temperatures and humidities for computer
rooms
Keep the ambient temperature in the computer room at a level that feeds comfortable
to the human body or somewhat lower. This precaution will not only prevent local
temperature rises in the computer room, such as those caused by equipment which
requires high heat dissipation, or stagnant air circulation, but will also allow some
time before the upper-limit temperature is reached even if the air conditioner fails.
In underfloor ventilation, humidity considerations require special consideration.
Normal air contains vapor. The higher the temperature is, the lower the relative
humidity is; the lower the temperature is, the higher the relative humidity is. For
example, air at a temperature of 24C (75F) with a relative humidity of 45% would
have a relative humidity of 65% at a temperature of 18C (64F) and could have a
still higher relative humidity as the temperature falls.
Air conditioners are not designed to detect subtle changes in temperature and
humidity in the entire computer room space. Generally, air conditioning is controlled
by detecting and regulating the temperature and humidity at the main unit or at each
of multiple air outlets. An air conditioner installed for underfloor ventilation detects
and regulates the temperature and humidity at a point near each air outlet. As such, a
nonuniform distribution of temperature and humidity may occur in the computer
room.
Table 4.1
C120-H007-08EN
lists recommended temperatures and humidities for computer rooms.
4.3 Air Conditioning Conditions
39