While performing Tunnel validation using z value of 46.4 and achieving exposure time of minimum 3 min during sterilization at temperature of 300 deg and more. Does this meet the acceptance criteria for depyrogenation & sterilization. I also want to know that what shud be the FH value, is it 3 min. or 30 min at 300 deg and Z= 46.4. Please help to clear my confusion[/quote]
As you calculate Fo values with base temperature 121oC and z=10oC on the same way you calculate Fh values but your base temperature is not 300oC, it is 250oC and z=46.4oC. It seems that your tunnel set temperature is 300oC. In this case, you let thermocouples go trough tunnel and calculate lethality. Fh/Fo is cumulative value and it grow with temperature. So, for tunnel Fh will start to raise at approx. 200oC and have a maximum in the sterilization/depyrogenation zone (highest rate). For entire cycle Fh should be above 30 minutes.