A：Precision requirements should be defined by the employer according to the characteristics of product; except for a few precision machining, there aren’t strict requirements for the precision of temperature and humidity in most clean rooms, while necessary requirements for the precision of temperature and humidity with such special precision machining process are empirical value of the employer after a lot of failures, which not each employer having the experience of failure is willing to disclose.
It should be noted that, if the precision of temperature is ＞2℃db, it’s hard to control RH to be ≤±5%RH; the lower is the precision of temperature and humidity, the less the difference between air outlet temperature and room temperature (?T), that is, higher air supply demands high power of forced draft fan.