Calibration and Performance Qualification Testing of Autoclaves.doc10/07/2006
Calibration and Performance Testing of Autoclaves - 23066 Calibration and Performance Qualification Testing ofAutoclaves.
What is calibration? Calibration is the process of determining the actual*temperature inside an
autoclave when a given temperature
is set.* Where ‘actual’ means ‘best estimate’. See ‘Uncertaintiesexplained’below. So why bother? Well, without a calibration – even with its uncertainties, the actual temperature inside theautoclave is unknown. The electronics may be wrong, the temperature probe may be
damaged, the pressure gauge – a very useful backup - may also be wrong etc. - Is it worth the risk if the process is not sterilising properly? - Is it worth the risk, in this litigious world, if the
autoclave is not covered by a calibration?Calibrating, particularly if a UKAS* calibration laboratory is employed provides a powerfuldemonstration, in a court of law, that due diligence has been properly exercised. It showsthat‘all reasonable care’ has been taken. * UKAS is the United Kingdom Accreditation Service. They are the sole organisationrecognised by the UK government to assess calibration laboratories against international
criteria.(go to www.ukas.org for more details.) What does it involve? The calibration engineer will insert a calibrated probe into an
autoclave and run it at a settemperature, taking sufficient readings to produce a calibration certificate. The actualprocedures used will vary from company to company but all UKAS accredited calibrationlaboratories will work to approved procedures. The data is then used to produce a calibrationcertificate. The engineer may also attach seals to prevent access to areas that allow thecalibration to be altered. Adjustment. Calibration does not always include adjustment of the
autoclave controls. Often themanufacturers’ control software is not accessible to untrained, third party engineers, forobvious reasons. If the
autoclave cannot be adjusted and is significantly out, then the settemperature can be adjusted to compensate the difference by using the data on thecalibration certificate. If for any reason adjustment of an
autoclave is not required the serviceengineer should be informed - preferably beforehand. What does it cost? This depends. The largest cost in the calibration is often getting the engineer to and from thesite. Once on site the work is generally straightforward, if rigorously controlled. It thereforemakes financial sense to choose a calibration company that has local engineers and is alsoUKAS accredited for the calibration. Calibration can also be performed as part of a routine
service visit at agreed intervals. This is often an economical solution. Performance qualification. This is one of several generic terms for testing an
autoclave - and its load - to ensure the loadis properly processed. Usually a calibrated, multi channel, data logger is employed for themeasurement so that considerable numbers of points in the load, together with salient pointson the
autoclave, can be logged. Analysis of these results can point to many problems in thesetup of the
autoclave or in the way the load is contained. Significant differences can be
