Monitoring the high and low point is not required, but unfortunately it seems so logical that it leads to tricky questions in audits. I have been asked the question many times and when answering that we don’t I follow with an explanation for why the single point that we do monitor is representative of the chamber as a whole in light of the qualification data. We do move our probe to the point farthest from the set point within the chamber as determined at each qualification and requalification. That point may be low or high, but the explanation has been sufficient to avoid the follow-up question I would expect–if that point happens to be high, what about the potential low point? Couldn’t it be out of range low at times and go undetected? My response to that, if it came up, would be to point out the very tight uniformity of the chamber. If your chamber uniformity is not tight, then the argument for not monitoring high and low points becomes weaker. I believe satisfied scrutiny on this point primarily because our procedures clearly state our qualification practices as related to probe placement and because of our very uniformly controlled chambers.
Reply To: Chamber MonitoringWalter Routh2022-10-21T12:17:37-04:00