Some time ago Dr. Larry Keener posted in LinkedIn that he had never seen a flash sterilization calculator that used to be a give away by several forms in the 1990s. I have a couple form that time, and I decided to try and recreate the slide rule.
With the help of some people in Reddit, I found a scale maker software and was able to prepare the scales. Then I made a printable calculator.
This calculator provides an estimate of the sterilization value for thermal processes. It can be used to estimate one of the parameters when the other 2 are known. Parameters: hold time (in seconds), F0, or Temperature
This calculators works for ºF or ºC by flipping the slide ruler.
It is available as a PDF for Letter paper in
Instructions:
Cut the shapes by the solid lines, cut the shadeed area window and fold by the dotted lines.
Assemble the envelope and place the slide ruler inside, with the number visible through the window
This computer must be used only as an estimate of the sterilization time and temperature needed for processing. Final process calculations must be performed by a qualified thermal process authority.
Distributed free under CC-BY-NC 4.0 in memory of the engineers who paved the way for thermal processing, we stand on the shoulders of giants.
Pablo M Coronel 2025