Thermal analysis for the explosive potential of peracetic acid is evaluated using the calorimetric testing. The timetemperature-pressure and flow regime data of peracetic acid are measured under adiabatic conditions by a vent sizing package 2calorimeter, which is capable of simulating real-time venting condition. The thermo-physical parameters of 40 wt% peracetic acidthrough calorimetric testing were calculated the reaction kinetics and evaluated by thermal analytical programming model forpressure relief consideration during a runaway scenario. The emergency relief system regarding to a gassy venting is calculatedby simplified vent sizing equations in a peracetic acid reactor during overpressure. The adiabatic calorimetry methodologycombining with fundamentals on homogenous flow model developed useful vent sizing criteria for proactive loss prevention ofperacetic acid process.