This is a test for steam penetration into the maximum size of load intended to be processed in the steriliser and complements the small test. The textile test pack is located in the centre of a full load of textiles. The test load is designed to represent the maximum mass of textiles which can be processed in the steriliser and is used to demonstrate that, at the levels at which cycle parameters are set, rapid and even penetration of steam into the centre of the load occurs sterilizing condition is achieved.

ISO17665:2024- Annex C.4.2

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Introduction

The full-load test is designed to demonstrate that, at the levels at which cycle variables are set, rapid and even penetration of steam into the centre of a load occurs, and the sterilizing condition is achieved in a test load of specified maximum mass and of sufficient size to fill the usable chamber space.

Temperatures and pressures should be recorded by independent measuring equipment.

Test Method

Place the standard test pack within the chamber in a position identified by the manufacturer as the most difficult to sterilize. This will normally be in the approximate centre of the chamber.

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 below the approximate centre of the top sheet of the test pack.

Load the rest of the usable chamber space with stacks of sheets. (The mass of fabric in the load should be equivalent to 7.5 ± 0.5 kg for a unit volume 300 mm x 300 mm x 600 mm.)

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 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;
• the equilibration time determined from the measured temperatures does not exceed 15 s for chambers up to 800 I and 30 s 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 measured temperatures are within the appropriate sterilization temperature band for the selected sterilization temperature;
• the measured temperatures do not fluctuate by more than ± 1°C;
• the measured temperatures do not differ from one another by more than 2°C;
• the indicated and recorded chamber temperatures are within 1°C of the temperature measured in the active chamber discharge;
• the indicated and recorded chamber pressures are within 0.05 bar of the measured pressure;

• the total cycle time is within the performance class stated by the manufacturer;
• at the end of the cycle the sheets are sensibly dry.

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