It is required to have a mechanism of air detector for porous load sterilization
Non condensable gas present in the input steam can be measured, what instrumentation is used for detecting of air in the chamber? How is this measured?

Dear Kamal.

Air detector is not a must.
Air detector can be used if you upgrade your SAL (Sterility Assurance Level) requirements. This is Hospital or State plicy. I know CSSD's which use A.D, Validate the cycle(s) quaterly! and thus don't challenge the cycle. But they use an Autoclave which is intended for this task: Clean steam acc. to HTM 2031and appropriate piping. The A.D is a very sensitive system (and expensive).
Good Practice (ISO 13683, AAMI/ANSI ST46), Daily B&D test, weekly leakage test, confirmation of effectivness by a PCD, routine maintenance,annual Validation will provide satisfying results.
The instrumentation is described in EN 285 as well as in HTM 2031

miki

This is an interesting question and the answer is complicated. Why should you employ an air detector to monitor porous loads?
An air detector (AD) is fitted to a porous sterilizer which employs vacuuum as a means of removing air from the load during sterilization (not required by bEN285).
It is used to determine whether any air or non-condensable gas (nitrogen CO₂, O₂) is present in the chamber and is in sufficent quanities to impair the sterilisation process.
The temperature type AD has two components, a temperature sensor and a controller.
The controller is set to a value of tempertaure which is set during an Air detection performance Test (>= 105 c) Ai r detection usually takes place at the peak of the first pulse so if the temp is > or equal to the temp controller, the cycle continues if however the criteria is not met the cycle fails and the process aborts.
An audible and visual alarm should be indicated, but as Miki states unless the AD is challenged on a regular basis (weekly) it a wasted resource so a correctly adjusted AD wiil contribute to product security but is not an alternative to effective maintenance

Regarding the non condensable gases measurement, it is quite difficult and expensive to add a mechanism inside the equipment.
However, the use of independant data loggers provide a concrete information on the steam quality. By measuring the deviation between temperature and pressure, the sensor will give you the quality of saturated steam compared to the famous "Regnault's tables". A deviation measured outside 2 % from Regnault's tables will show the presence of external gases and / or residual air inside the chamber.
In addition to this, you will know if you are sterilizing with a wet or superheated steam.

Best Regards