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CAN/CSA Z23747-18: Peak Expiratory Flow Meters – Technical Overview for Pulmonary Function Assessment
Understanding the Canadian Adoption of ISO 23747:2015 for Peak Expiratory Flow Meters
CAN/CSA Z23747-18 is the Canadian national adoption of ISO 23747:2015, establishing safety, performance, and labeling requirements for peak expiratory flow (PEF) meters intended for the assessment of pulmonary function in spontaneously breathing humans. This standard applies to both standalone PEF meters and those integrated into multi-function respiratory devices. Manufacturers, clinicians, and regulatory bodies rely on this standard to ensure consistent and reliable measurement of expiratory airflow in primary care, emergency, and home settings.
Scope and Application
This standard specifies requirements for peak expiratory flow meters used to measure the maximum flow rate generated during a forced expiration starting from maximum lung inflation. It covers:
- All meter types — mechanical, digital, and hybrid designs
- Devices intended for both adult and pediatric populations
- Meters used in both clinical and self-monitoring environments
The standard does not apply to spirometers that measure forced expiratory volume in one second (FEV1) or other pulmonary parameters, unless they incorporate a PEF measurement function. For devices that combine PEF with other measurements, only the PEF element must meet Z23747-18; other functions must comply with their respective standards (e.g., ISO 26782 for spirometers).
Key Implementation Tip: When designing a multi-functional respiratory device, perform separate validation of the PEF channel against Z23747-18. The presence of additional FEV1 or FVC measurements does not exempt the PEF module from full compliance.
Technical Requirements and Specifications
The standard defines mandatory performance criteria that all PEF meters must meet when tested under defined laboratory conditions. The following table summarizes the core technical requirements:
| Parameter | Requirement (Z23747-18) | Test Condition / Note |
|---|---|---|
| Measurement range | 100 L/min to 800 L/min (adult models) 50 L/min to 400 L/min (pediatric models) | Extended ranges allowed if accuracy is maintained outside these limits |
| Accuracy | ±10 % of reading or ±10 L/min, whichever is greater | Errors must be within the limit at all points across the range |
| Repeatability | Within ±5 % of the mean of three consecutive measurements | Applicable to both mechanical and electronic meters |
| Backpressure limitation | Pressure drop ≤ 1.0 kPa at 400 L/min ≤ 2.0 kPa at 800 L/min | Ensures minimal resistance that could alter patient exhalation |
| Calibration stability | No drift > ±2 % over 12 months of normal use or per manufacturer’s specified interval | Manufacturer must specify calibration frequency in the user manual |
| Environmental sensitivity | Accuracy preserved at 15 °C to 25 °C and 30 % to 75 % RH | Additional humidity/temperature testing required for extreme‑condition claims |
| Battery life (electronic meters) | Minimum 6 months or 3000 measurements, whichever comes first | Must display a clear low‑battery indication well before failure |
Mechanical and Constructive Requirements
In addition to performance metrics, the standard mandates specific design features:
- Mouthpiece: Should be easily replaceable and hygienic; designs must discourage reuse without cleaning.
- Display: Digital meters must show PEF in L/min with increments of 1 L/min. Mechanical meters must provide a clear scale and indicator that locks at the peak flow.
- Marking: Each device must be marked with the standard number, manufacturer identity, model, and date of manufacture.
Warning: Mechanical PEF meters with moving parts must be tested for friction and repeatability after 5000 cycles to verify endurance. Failure to maintain accuracy after endurance testing is a common non‑compliance issue.
Implementation Highlights for Manufacturers and Clinicians
Implementing CAN/CSA Z23747-18 requires close attention to both design and documentation. The following points highlight the most critical aspects:
Design and Validation
Manufacturers should use a flow generator calibrated to a reference standard traceable to ISO 17025 or an equivalent national measurement institute. Validation testing must cover the entire declared range in both forward (ascending) and reverse (descending) flow sequences. The standard also requires a clinical usability evaluation with a representative user group (patients and healthcare providers) to confirm that the instructions for use are clear and that the meter is ergonomically acceptable.
Success Criterion: A PEF meter that passes the accuracy and repeatability tests with margins of ±5 % (instead of the required ±10 %) will have a higher probability of maintaining compliance over its lifetime. Consider designing to half the allowable error to absorb drift.
Labeling and Instructions
The standard stipulates content requirements for user manuals, including:
- How to perform a correct forced exhalation maneuver
- Recommended cleaning and disinfection procedures
- Calibration schedule and method
- Expected accuracy and limitations (e.g., not for use in patients with recent oral surgery)
All labeling must be in both English and French for the Canadian market.
Compliance and Certification Notes
Demonstrating compliance with CAN/CSA Z23747-18 requires a combination of type testing, quality system documentation, and ongoing vigilance. Key steps include:
- Type examination: Submit one or more representative samples to an accredited laboratory (e.g., CSA Group, UL, Intertek) for full performance testing against the criteria in Table 1 above.
- Quality management system: The manufacturing facility must maintain a QMS compliant with ISO 13485 or the applicable Canadian Medical Devices Regulations (SOR/98-282).
- Post‑market surveillance: Manufacturers must monitor complaint data and recalibrate or update the device if field accuracy drifts exceed the standard limits.
Health Canada recognizes CAN/CSA Z23747-18 as a voluntary standard, but compliance significantly eases the licensing process for Class II medical devices. A Declaration of Conformity and technical file referencing the standard must be available for review upon request.
Critical Non‑Compliance: Any PEF meter that fails the accuracy requirement at the lower end of its range (e.g., errors > ±10 L/min at 100 L/min) is considered hazardous because it can lead to misclassification of asthma severity. Immediate corrective action and field‐safety corrective action (FSCA) may be required.
For clinicians, using a Z23747‑18‑compliant meter ensures that longitudinal tracking of PEF variability is reliable. It is recommended to document the standard number and calibration status of the meter in the patient record.
Frequently Asked Questions
Q: How does CAN/CSA Z23747-18 differ from the international ISO 23747:2015?
A: The Canadian standard is technically identical to ISO 23747:2015. The only differences are the addition of Canadian national devi
A: The Canadian standard is technically identical to ISO 23747:2015. The only differences are the addition of Canadian national devi