Guidance published on quality of water for sterilizers and washer disinfectors

International technical specification adopted in UK as a Published Document.

The Technical Committee responsible for standards on sterilization and washer disinfectors, ISO TC 198 – Sterilization of health care products – has a portfolio of standards that cover validation and routine control of sterilization processes, general requirements for sterilizers and standards for washer disinfectors. On January 2021, the committee published its first standard for sterilizing equipment; ISO TS SO/TS 22421:2021 - Sterilization of health care products — Common requirements for sterilizers for terminal sterilization of medical devices in health care facilities.

Following review of its standards portfolio, it was recognized that the quality for water was a common aspect across relevant published standards and that different specific standards dealt with the topic in different ways. In addition, it was recognized that there was no comprehensive guidance provided in the individual specific standards on controlling or maintaining water quality. ISO/TS 5111:2022 - Guidance on quality of water for sterilizers, sterilization and washer-disinfectors for health care products -was developed to survey the requirements for water quality in different sterilizer, sterilization and washer disinfectors standards and provide associated guidance on monitoring, controlling and maintaining water quality. It has been implemented in UK as PD ISO/TS 5111:2022.

PD ISO/TS 5111:2022 is the first edition of a Technical Specification giving guidance on the quality of water for use in sterilizers, sterilization processes and washer disinfectors used for processing medical devices and other healthcare related products. The quality of water supplied to sterilizers and washer disinfectors affects the functioning of the equipment and the safety and performance of the processed healthcare product. The quality of water can vary significantly between different locations because of differences in the source of the water, the way that it is distributed and the conditions in which it is stored. These differences can affect the physical, chemical and microbiological attributes of the water.

• Water used in sterilizers and washer disinfectors can:
• Come into direct contact with the healthcare product;
• Be used to generate steam that comes into direct contact with the healthcare product;
• Heat or cool the product without direct contact, either as water or steam; or,
• Operate or control elements of the equipment.

Existing standards for sterilizers, sterilization processes and washer disinfectors provide specific requirements for water quality in those particular applications.
PD ISO/TS 5111:2022 aims to bring together the requirements from these individual standards and support those requirements with guidance on:

• Water treatment systems;
• Water distribution and storage;
• Monitoring, maintenance and control of water quality; and,
• Cleaning and disinfection of water treatment systems.

PD ISO/TS 5111 does not modify the requirements laid down in the relevant standards for sterilizers, sterilization processes or washer disinfectors. The requirements for different processes vary between the different sources. By highlighting such differences, it is hoped that any discrepancies between processes can be addressed in future revision to the source documents.

Manufacturers and users of sterilizers, sterilization processes, washer disinfectors and water treatment systems will be interested in the comparison and requirements from different standards and the additional guidance given on attaining and maintain the required quality of water for the different processes.