Steam Sterilization Cycle Parameters (Pre-Vacuum)

I am in the process of validating a new autoclave. A very old autoclave (circa 1987) was replaced with a modern autoclave. The pre-vacuum pulse depth and steam charge level was 3.0 psia and 21.0 psia, respectively. With the new more modern autoclave the manufacturer recommends the pre-vacuum pulse and depth and steam charge level at 1.45 psia and 15.2 psia. Can someone please explain why this would be better and more efficient parameters for air removal? Any insight would be helpful. Thanks.

The new cycles high/low are probably a standard cycle the manufacturer has used for various other clients. There probably isn’t too much of a difference between the two cycles, honestly. They probably are very similar in regards to efficiency of removing air. At this point, you’re not trying to steam the parts (during pulse phase) you are trying to remove air, and both cycles are probably similar. DId you look at the number of pulses required also. That is another parameter which might be different based on the recommendation of the autoclave vendor, but maybe not.

Regarding validation, I hope you are going to re-validate the entire cycle (IQ, OQ, PQ, PV) - you might want to do an engineering study to show that all the air gets removed with the new parameters.

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