ISO 18472 pdf download – Sterilization of health care products —-Biological and chemical indicators 一-Test equipment

ISO 18472 pdf download – Sterilization of health care products —-Biological and chemical indicators 一-Test equipment.
The resislorneter is intended to be used to expose test samples under stated test conditions, and therefore shall be capable of producing cycle sequences as required for specific test methods. Depending upon the test methods defined in ISO 11138-2, ISO 11138-3. ISO 11138-4 and ISO 11140-1. the resistometer utilized need only verify those limits necessary to characterize the chemical or biological indicators.
NOTE The following specifications define the conditions to be achieved in the vessel ii w$iich the sample is to be placed, but the means by which these conditions are to be oontroed are not addressed.
4.2 Measurement and control capabilities
The following performance requirements define the measurement and control capabilities for steam, ethylene
oxide, dry heat, and vaporized hydrogen peroxide resistometers
4.3 Test methods
The equipment specified in this International Standard shall be used with the detailed test methods given In the appropriate parts of ISO 11138 and ISO 11140.
NOTE The dawned performance tolerances for chemical and b.okcat sidicators are based on the speaned exposure conditions without allowance for the operational tolerances of the test equipment.
4.4 Leak test
4.4.1 With the temperature stabilized and the diamber empty (except for fixed furniture and necessary monitoring sensors) start the test cycle. When the pressure in the chamber has reached or is below the value corresponding to the lowest operating vacuum of the test cycle air removal stages, close all the valves connected to the chamber and stop the vacuum pump. Observe and record the time, t1, and the absolute pressure, Pi• Allow evaporation of condensation in the chamber for 300 s ± lOs and then observe and record the absolute pressure, p2. in the chamber and the time, 2’ After a further 600 s ± lOs, again observe and record the absolute pressure p, and the time. t3.
The resistometer may be fitted with a test cycle for air leakage that will carry out this procedure automatically and disptay the air leakage in kPa/min (mbar?rnin).
4.4.2 At the end of the test calculate the rate of pressure rise for the 600 s period.
NOTE 1 If the value of (p2 – p,) as greater than 2 kPa (20 mbar). this could be due to the iratial presence of excessive condensate in the steflhzer charver
NOTE 2 In a closed vessel at 4 kPa pressure, the pressure changes by approximately 0,1 liPa (1 mbar) for each 10 “C change in tenWerature over the range 20 “C to 140 C at 7 kPa (70 mbar) the change is approximately 0,2 kPa (2 rabar) The test can be compromised if the temperature changes by more than 10 “C during the period ii which the chamber pressure is monitored.
4.5 Steam reslstometer performance requIrements
4.5.1 Measurement accuracy
The sensors used to measure temperature, vacuum and pressure from within the steam resistometer shall have a response lime as specified in Table 1. The system used to record time, temperature. vacuum and pressure from within the steam resistometer shall be capable of operation with a resolution and accuracy within the scale range specified in Table 1.
4.5.4 General steam resistometer requirements
4.5.4.1 The chamber shall be supplied with saturated steam from a source external to the chamber. The steam supply shall meet the requirements of ISO 11 140-4 Means shall be provided to ensure that the test items are riot wetted by entrained water droplets in the steam supply.
4,54.2 Air admitted at the end of the cycle shall be filtered through a filter having the capability of removing not less than 99,5 % of 0.5 pm partides
4.5.4.3 The sample holder shall allow the indicator to be exposed to the test conditions in the manner intended by the indicator manufacturer.
The various types of indicator may requwe customized sample holders, Sample holders might have to be constructed to hold test items in different vertical and horizontal attitudes to test performance differences Consult the indicator manufacturer for guidance when verifywig label claim performance.
4.5.5 Air leakage test
When determined by the method given in 4.4, the air leakage rate shall not be greater than 0.13 kPalmln (54.8i1’) where is the chamber volume in litres.
4.5.6 Operation of steam resistometer
4.5.6.1 The chamber shall be designed such that the formation of condensate dunng any stage of the operating cycle does not affect the required test conditions. In order to avoid excessive condensate formation during the operating cycle it might be necessary to provide thermostatic control of the inner surfaces of the resistorneter so that they can be maritained at a specified temperature (e.g. the exposure phase temperature).