i have to qualify a load of garments in the autoclave.The garments are used in 2-8deg c aseptic condition and therefore we purchased some special type garments which are made up of with some material that absorb heat and maintains it and when we try to carry out the heat penetration studies,at 121deg c in the autoclave,the garments are showing the temperature of 135deg c in the data logger display.we cross checked the steam line and the pressure which is maintaining at 1.17bar.so can anybody please help me how to justify this situation and help me to know how to carry out the validation process and what type of changes are to be made.
Thanks in advance.
It is very interesting, during heat penetration studies the garments are archiving 135 C instead of 121 C, indicates that the temperature is increasing up to 14 C.
In this case, garments can be sterilsed in a lower temperature with longer duration (107 C) so that the temperature can atchive 121 C during heat penetration.
(intitially develop the sterilisation cycle) The efficiency of sterilization can be checked using biological indicator/ chemical indicator.
The rational for sterilizing the garment at lower temperature should be justified in the study protocol.
sterilization at 107oC is not a solution. Saturated steam at 1.17 bar should have 122.81oC, not 135oC, so problem is that you have superheated (dry) steam. Solution is conditioning garment not to apsorb wet from saturated steam. If you have sterilization at 107oC I am not sure that temperature will be 121oC (I doubt that it is linear) and even if you have 121oC it i not saturated steam (boundary phase steam), it is dry superheteated steam.
- check your offset settings in your data logger.
- cross verify your temperature sensor and data logger with a sensor and data logger of a external agency.
- the material with which the garment is made of may also have some effect in retaining the temperature or for over heating.
- use a chemical indicator which indicates over heating.