Overview
EN ISO 20789:2019 - titled Anaesthetic and respiratory equipment - Passive humidifiers (ISO 20789:2018) - specifies requirements for passive humidifying devices commonly called cold bubble-through or cold pass-over humidifiers. Adopted by CEN as a European Standard, it sets out safety, testing and information requirements for passive humidifiers used with anaesthetic and respiratory systems.
Key topics and technical requirements
The standard covers technical and practical aspects including:
- Scope and definitions: clear identification of passive humidifier types (cold bubble‑through / cold pass‑over) and terminology.
- General test requirements: test conditions, water level, gas flowrate and leakage specifications, and acceptable testing errors.
- Mechanical safety: stability, protection against unwanted lateral movement, overflow control, and overpressure requirements.
- Performance: humidification output requirements and methods (see Annex C – determination of humidification output).
- Compatibility and materials: guidance on compatibility with substances, biocompatibility expectations, and mechanical strength.
- Breathing system interfaces: requirements for breathing system connectors and ports (air/oxygen inlets, outlet connectors, filling ports, accessory and monitoring probe ports).
- Identification and documentation: marking, labelling, instructions for use, packaging, symbols and unique version identifiers.
- Cleaning, disinfection and maintenance: procedures and special considerations for home healthcare environments.
- Safety aspects: single‑fault conditions, fire prevention, and physiological effect information.
- Usability and annexes: usability requirements, informational annexes (rationale, symbols, terminology and references).
Practical applications and users
EN ISO 20789:2019 is intended for stakeholders involved in the design, manufacture, testing, procurement and safe use of passive humidifiers in clinical settings:
- Medical device manufacturers - to design and validate passive humidifiers that meet accepted safety and performance criteria.
- Test laboratories and conformity assessors - for methodical evaluation of humidification output, leakage and mechanical safety.
- Clinical engineers and biomedical technicians - for selection, installation and maintenance guidance.
- Hospitals and procurement teams - to specify compliant equipment and review accompanying documentation/instructions.
- Regulators and standards bodies - for harmonized requirements across Europe (CEN adoption) and alignment with ISO/TC 121 guidance.
Related standards and references
- Original international text: ISO 20789:2018 (adopted as EN ISO 20789:2019).
- Prepared by ISO/TC 121 (Anaesthetic and respiratory equipment) and adopted by CEN/TC 215.
For product development, testing or compliance, consult the full EN ISO 20789:2019 document and its normative annexes for detailed procedures and legal requirements.
