formed in general,the type ofmaterials that will be routinelysterilized should be considered at all times when setting ob-jectives for validation (3).In accordance with the purpose ofthe validation,scientifically sound acceptance criteria that canbe accurately evaluated by monitoring the physical parametersofthe process should be established.

The qualification–validation procedures should be performedusing approved protocols developed before the procedures areinitiated (4).A description ofthe autoclave process,cycle types,parameters,and performance specifications must be completed.The protocols should clearly state the objectives ofthe valida-tion and define the scope ofthe activities for each stage oftheprocess.Time frames and general acceptance criteria shouldalso be part ofthe protocols.Each stage ofvalidation must bedocumented and approved.

Qualification–validation consists ofa series oftests,each ofwhich includes an objective,a method,acceptance criteria,andtest results.The responsibility for testing must be assigned toeither the manufacturer or user,agreed on,and documented.To perform a proper validation,several items are requiredsuch as a temperature recorder (data logger) that can recordand accumulate temperature data collected by thermocouples,a calibrated thermometer,and a computer that can analyze rawdata and compute F0values (5).A laminar-flow hood,biolog-ical indicators (BIs),access to an incubator (55–60 C),a tem-perature bath,and an ice bath for accuracy verification ofthethermocouples also are compulsory elements.

Commissioning or pre-installation qualification (IQ)–operationalqualification (OQ) phase.As a prerequisite to qualification ofbothnew and refurbished autoclaves,a user requirement specifica-tion document containing key equipment requirements shouldbe developed and approved.Referring to this document helpsprevent purchases ofunsuitable and inappropriate equipmentthat can be difficult to qualify for the intended purpose.Afterits approval and authorization,the document must be passedto relevant vendors before receipt ofquotes or offers for missioning is the first step ofqualification (6) and con-sists ofobtaining evidence that equipment has been providedand installed in accordance with its specifications and that itfunctions within predetermined limits when operated as di-rected by its instructions.The company installing the unit mustdeliver and commission the autoclave and must offer technicalsupport to the owner until the autoclave is in the proper con-dition for use.Performing a proper commissioning saves timeand money and provides the necessary confidence in the per-formance ofthe equipment.

IQ–OQ phases.The IQ and OQ phases can be instituted sep-arately or simultaneously.During the IQ and OQ phases,var-ious features ofthe autoclave are examined and tested for properfunctioning.This procedure includes tests ofthe chamber de-sign,pressure vessel,and door safety interlock system and in-spections ofthe chamber jacket,steam traps,electrical circuits,pressure and temperature indicators,vacuum pumps,vent fil-ters,and steam supply to the chamber.

Usually the IQ document indicates the location ofthe docu-mentation for the equipment (which must include a checklistcontaining specifications and identification ofequipment or

components by description,model,and serial number),the in-struction manual,the troubleshooting and preventive mainte-nance schedule,the electrical and piping drawings,and the dia-gram ofthe programmable logic controller (PLC).

Calibration of command and control instruments.During the IQ phase,the calibration ofall critical instruments—process controllers,temperature sensors,pressure gauges,timers,and measuringand recording instruments—should be performed.It is alsoimportant to know the degree ofaccuracy ofthe instrumentsused to calibrate the gauges.The accuracy level ofthe cali-brating instruments must exceed the accuracy level ofthe auto-clave’s control,measuring,and recording systems (1,7).Like-wise,the control,measuring,and recording instruments musthave an accuracy level that fits the purpose ofthe autoclave.When the desired level ofaccuracy is not known,standardsmust be consulted.

The performance ofcalibration test instruments should betraceable to national reference standards.All calibration pro-cedures must be fully documented.Calibrations must be com-pleted before any other validation tests are started.The cali-bration can be performed either before installation ofthe unitor in situ after the unit is placed in its operating site.The ad-vantages ofcalibrating in situ include the ability ofa sensor orgauge to provide accurate information about the environmentthat the unit is monitoring when compared with a known stan-dard (6).This type ofcalibration is more rugged and providesa more accurate image ofthe process being monitored.

Requirements for thermocouples.To monitor temperatures attainedat various locations throughout the chamber,temperature-measuring devices called thermocouplesare used.The thermo-couples are connected to computerized multichannel record-ing systems that can record and print temperature data.Forvalidation purposes,type T thermocouples are recommendedbecause they are stable throughout a wide temperature range.Depending on the chamber size,10–20 thermocouples mustbe used per cycle.Thermocouples should not be placed in thechamber through the door gasket because they can be easilydamaged when loading or unloading the chamber,which canalso create a leak that will affect the normal working condi-tions ofthe autoclave.One should place the thermocouples inthe autoclave chamber by means ofa feed-through assemblyconnected to a suitable port.After purchasing a new autoclave,this port must be documented during the IQ phase.

One must also verify the accuracy ofthe thermocouples totraceable secondary standards at two significant temperatures(e.g.,the freezing and boiling point ofwater) at the beginningand end ofeach phase ofthe qualification.This procedure canbe performed by immersing the thermocouples and a referencecalibrated thermometer in water maintained at the previouslymentioned temperatures and monitoring the temperature val-ues ofboth the thermocouples and the reference thermometerfor a certain period oftime.Accuracy ofthe thermocouplesshould be at least 0.5 C.Temperature accuracy is especiallyimportant in steam-sterilization validation because an error ofjust 0.1 C measured by a faulty thermocouple will produce anerror of2.4% in the calculated F0value (8).All inaccurate ther-mocouples should be discarded.