This is a test for steam penetration into a standard test pack. This test pack is used to identify A level of air removal or reduction in the level of NCGs in the steam within the chamber sufficient to qualify the sterilisation process for a wide range of cannula, metal and textile products. For this test a number of temperature sensors (typically 5 sensors) are located at different levels within the standard test pack around the vertical axis.

ISO 17665:2024 - Annex C.4.1

---

 

Introduction

This test is used to demonstrate that after the air removal stage of the operating cycle, sterilizing conditions are obtained within the chamber and standard test pack. The more air there is to remove, the more exacting will be the test; that is why the pack is used by itself in an otherwise empty chamber.

Temperatures and pressures should be recorded by independent measuring equipment.

Test Procedure

Place a standard test pack in the chamber with the bottom of the pack supported 100-200 mm above the centre of the chamber base.

Place three temperature sensors in the following positions:

• one in an active chamber discharge;
• five within the test pack as detailed in BS EN 285 (the wire from the sensors should be carefully arranged to prevent steam tracking along it);
• one placed in the free space 50 ± 5 mm above the approximate centre of the upper surface of the test pack.
• Connect a pressure recorder (or test gauge) to the chamber.

Start the operating cycle, with standard drying time, and take readings as described for the automatic control test.

If a test pressure recorder is being used, measure the chamber pressure at the approximate mid-point of the holding time.

The test should be considered satisfactory if the following requirements are met:

• the requirements of the Automatic Control Test are met;
• during the plateau period the temperature measured above the test pack does not exceed the temperature measured in the active chamber discharge by more than 5°C for the first 60 s and 2°C for the remaining period;
• the equilibration time determined from the measured temperatures does not exceed 15 seconds for chambers up to 800L and 30 seconds for larger chambers;
• the holding time determined from the measured temperatures is not less than that specified for the selected sterilization temperature;
• during the holding time the temperatures measured in the reference measurement point and in the centre of the test pack:

• are within the appropriate sterilization temperature band;
• do not fluctuate by more than ± 1°C;
• do not differ from one another by more than 2°C;

• during the holding time:

• the indicated and recorded chamber temperatures are within 1°C of the temperature measured in the reference measurement point;
• the indicated and recorded chamber pressures are within 0.05 bar of the measured pressure;

• for sterilizers using vacuum as the sole method of drying:

• the duration of the drying stage is not less than 3 minutes;
• the chamber pressure at the end of the stage does not exceed 40 mbar absolute;

• at the end of the cycle the sheets are sensibly dry.

Return to Schedule of Tests