Understanding CAN/CSA Z23328-2-03 (R2018): Breathing System Filters for Anaesthetic and Respiratory Use – Non-Filtration Aspects

Scope and Purpose

CAN/CSA Z23328-2-03 (R2018) is the Canadian adoption of the international standard ISO 23328-2:2002, titled Breathing system filters for anaesthetic and respiratory use — Part 2: Non-filtration aspects. This standard specifies requirements and test methods for the mechanical, fluid dynamic, and other non-filtration performance characteristics of breathing system filters (BSFs) intended for use in anaesthetic breathing systems and respiratory circuits.

While Part 1 (CAN/CSA Z23328-1-03) addresses filtration performance, Part 2 focuses on aspects such as:

• Biocompatibility and materials safety
• Mechanical integrity (e.g., burst pressure, leak testing)
• Airflow resistance (pressure drop)
• Dead space and internal volume
• Connections and port compatibility
• Labelling and packaging requirements

First published in 2003 and reaffirmed in 2018 without technical change, the standard remains current for Canadian medical device manufacturers, healthcare facilities, and regulatory bodies. It applies to both single-use and reusable filters intended for placement in the breathing system between the patient and the anaesthesia machine or ventilator.

Technical Requirements

Materials and Biocompatibility

The standard mandates that all materials in contact with the patient or breathing gases shall be evaluated for biocompatibility according to ISO 10993 series (or equivalent). Materials must not release particles, fibres, or volatile compounds at levels that could pose a risk to patients or healthcare personnel. The filter medium itself must be compatible with common anaesthetic agents and disinfectants (if reusable).

Mechanical Integrity

Filters must withstand a static internal pressure of at least 100 % above the maximum working pressure (typically 60 kPa) without rupture or permanent leakage. A leak test at 3 kPa ensures that the filter housing and seals maintain integrity under negative pressure scenarios. For reusable filters, the standard requires verification after the specified number of reprocessing cycles.

Flow Resistance (Pressure Drop)

Pressure drop at a specified continuous flow rate (typically 30 L/min for paediatric filters, 60 L/min for adult) must be within manufacturer-declared limits. The test method uses a calibrated flow source and differential pressure transducer with an accuracy of ±2 %. Table 1 summarises typical classification thresholds defined in the standard.

Table 1: Pressure drop thresholds (informative based on typical manufacturer claims)

Dead Space and Internal Volume

The internal volume of the filter (including both ports) must be declared by the manufacturer. For paediatric filters, dead space should not exceed 10 mL; for adult filters, it must be less than 50 mL. The standard provides volumetric measurement methods using water displacement or gas dilution techniques.

Connections and Port Compatibility

All patient and machine ports must conform to ISO 5356-1 (22 mm conical connectors) or ISO 5356-2 (luer locks for paediatric applications). Additional requirements include secure engagement, absence of sharp edges, and tamper-evident features for single-use products.

Labelling and Instructions

The standard requires that each filter unit and its packaging display:

• Intended patient population (adult, paediatric, neonatal)
• Maximum working pressure and flow rate range
• Single-use or reusable status with reprocessing instructions where applicable
• Batch/lot number and expiry date
• Symbol for medical device per ISO 15223

Implementation Highlights

Manufacturers seeking compliance with CAN/CSA Z23328-2-03 (R2018) should incorporate the following into their design and quality processes:

• Risk management per ISO 14971: Non-filtration aspects (e.g., occlusion by humidity, chemical degradation) must be addressed in the risk analysis.
• Design verification testing: Formal tests for pressure drop, leak, burst, and dimensional checks shall be performed on representative production samples.
• Stability programme: For single-use filters, accelerated aging and real-time aging tests validate the shelf life; for reusable filters, the number of reprocessing cycles must be validated.
• Clinical evaluation: While Part 2 focuses on bench tests, the manufacturer must provide clinical evidence that the filter does not significantly affect ventilation or gas exchange.

Healthcare providers should also consider the standard when selecting filters for specific patient groups. For example, a filter with dead space greater than 30 mL should not be used in neonatal circuits without careful assessment of rebreathing potential.

Compliance and Regulatory Notes

While this standard is voluntary in Canada, it is referenced by Health Canada as a recognised consensus standard for demonstrating safety and effectiveness under the Medical Devices Regulations. Manufacturers of Class II / III devices (breathing system filters are typically Class II under Rule 7) may apply the standard to support a Medical Device Licence (MDL) application.

Key points for compliance:

• A declaration of conformity to CAN/CSA Z23328-2-03 (R2018) must be backed by a technical file containing test reports, design documentation, and a risk management file.
• The standard requires periodic re-testing if the design is modified or if production materials change.
• For imports, ISO 23328-2:2002 is also widely recognised, but Canadian labelling (bilingual English/French) may be required in addition to the standard’s requirements.

It is important to note that the 2018 reaffirmation did not update the technical content; however, manufacturers should still consider current Canadian guidance documents and any relevant amendments to the Medical Devices Regulations that have come into force since 2018.

Overall, adherence to this standard, together with Part 1 and applicable international standards (ISO 5356, ISO 80601-2-13 for anaesthesia ventilators), forms a solid foundation for the safe and effective use of breathing system filters in Canadian healthcare settings.

Frequently Asked Questions

© 2026 Standards Publications. This article is for informational purposes and does not replace the full text of CAN/CSA Z23328-2-03 (R2018). Always refer to the official standard for precise requirements.