Definition(s)
Tempered System
Tempered systems are those in which the unwanted reaction produces condensable products and the rate of temperature rise is tempered by liquid boiling at system pressure. Typically, tempered systems are liquid-phase reactions in which a reactant (or solvent) is a major portion of the reactor contents.
Source: API STD 521, Pressure-relieving and Depressuring Systems, Fifth Edition, January 2007 (Addendum May 2008). Global Standards