Steam Sterilizer Validation
The process of sterilization within a chamber is a critical process and there is
a regulatory requirement for validation of the process in most countries.
Although validation requirements and quality assurance requirements vary in detail, the common theme is that it must be shown that sterilization has been achieved. Validation is defined as the documented procedure of obtaining, recording and interpreting results to ensure that the sterilization process has been and will be consistently effective.
Thermal validation consists of accurately measuring the temperature at critical points within the sterilization chamber throughout the process. Process sterilization temperature with steam is carried out at 134°C at a pressure of 3 bar. The sterilizer is required to heat all parts of its load up to the specified temperature for a specified period long enough to achieve the desired sterility.
In order to achieve good steam penetration of porous loads it is necessary to remove as much air as possible from the chamber and load prior to the sterilization hold phase. TQSoft™ thermal validation systems can automatically calculate and alert critical operational parameters with its Interval Calculations feature.
Steam quality can also be a critical factor in the efficiency of a steam sterilization. Steam test kits can be used to measure steam quality. Some companies claim that correlating measured chamber temperature with measured chamber pressure using standard saturated steam tables can monitor steam quality by controlling the Lethality & Pasteurization calculation based on correlation limits. TQSoft™ thermal validation software provides configuration options for this.
Problems with sterilization can occur with the spread of temperatures within the load. It is essential to identify the coolest and hottest part of the load and calculate deviations and fluctuations. Many companies have their own ideas on analysis, and TQSoft™ thermal validation systems can provide flexibility with its Interval Calculations feature.
The accuracy of the sensors and data acquisition hardware used to perform thermal validation is critical. Calibration and Calibration Check operating procedures are indispensible to normal acceptable validation practice, no matter what sensors are used (RTD’s, thermistors or thermocouples). The validation report must show that thermocouples, sensors, calibration and data acquisition equipment have been checked against a traceable standard at regular intervals. Thermocouples should be checked before and after a validation study. RTD’s and thermistors require less frequent checking, usually periodically every 6 months.
Generally thermocouple accuracy is required to be +/- 0.5°C.
TQSoft™ thermal validation software can help achieve these accuracies by providing simple to operate automated calibration and calibration checking procedures and reports. TQSoft™ also stores all validation and calibration equipment details in a Test Equipment Database management system. Before a validation study the engineer can tick the items of equipment in use and TQSoft™ stores this information in each validation record. This allows users to create audit reports on individual items of the calibration or validation equipment.
Thermocouples have a limited life span and remote logger batteries can run low causing expensive problems during the validation process. TQSoft™ thermal validation software tracksthermocouple and logger usage and allows engineers to set limits.
Because of the variety and variation of processes run within steam sterilizers, validation engineers should have a method to store test parameters and calculations to be able to repeat tests and reproduce reports quickly and efficiently. This is periodic revalidation. TQSoft™ thermal validation systems provide a database of ‘Test Specifications’ which can be re-used and easily adapted to new requirements.
TQSoft™ thermal validation software provides a Reporting and Report Management module which can provide a large degree of automation to report production, and allow reports to be built, managed, converted to PDF, emailed and archived.
TQSoft™ thermal validation software provides compliance with FDA regulation on electronic signatures in 21CFR Part 11 and has been developed and maintained according to GAMP.
The TQSoft™ thermal validation system is used by most leading autoclave validation companies, and at leading training establishments in the UK for HTM2010 HTM01-01 and EN554 and EN285 compliance.