Steam sterilization--the response of the test pack

The authors obtained temperature recordings from nearly 400 experiments with the standard test pack as defined in the prEN 285 as a basis for methods to evaluate conditions influencing steam sterilization. A new method to scale the duration and the extent of an air pocket (penetration fault) is presented. This method proved suitable for the interpretation and quantification of substantial correlations between the effect of a fault, the volume of the sterilizer chamber, and the rate of pressure change in the chamber. The coolest spot was found near the center of the test pack in only 17% of the tests. The air pocket was found to be an anomaly best elucidated by statistical methods. The prevailing influence of the rate of pressure change does not allow the establishment of limiting values for any fault, such as leakage rate or air dilution in the chamber, except as applied to a well-defined sterilizer. The penetration fault caused by an air leak does not depend on the chamber volume. The effects of residual air and induced air on the penetration fault are fundamentally different. Faults caused by those different air sources should be distinguished from each other even though both cause air pockets.