Overview
ISO 16900-8:2015 specifies laboratory methods to measure the air flow rates delivered to the wearer by assisted filtering respiratory protective devices (RPD). It is part of the ISO 16900 series of test methods for RPD performance and is intended to supplement performance standards by defining repeatable test procedures for complete devices or parts of devices where breathable gas is actively supplied.
Keywords: ISO 16900-8:2015, respiratory protective devices, assisted filtering RPD, air flow rate measurement, interactive flow rate.
Key topics and requirements
- Scope and definitions: Covers assisted filtering RPD and key terms such as interactive flow rate, averaged interactive flow rate (averaged over 10 breathing cycles), measured maximum/minimum flow rate.
- Prerequisites: Performance standards or test programs must specify number of specimens, operating conditions (flow settings, battery charge), designated temperature range, appropriate headform(s)/torso and any pre-conditioning.
- General test conditions: Ambient test range and tolerances are specified (e.g., nominal values with typical ±5% tolerance; ambient conditions guidance). Measurement uncertainty is addressed in Annex A.
- Two principal test methods:
- Zero back pressure method - suitable where interactive flow is effectively constant (e.g., Respiratory Interface class L or some class T setups). Test equipment includes headform, torso (where needed), controllable blower/suction device, calibrated flow meter, differential pressure sensor and an airtight box or lightweight bag.
- Interactive flow rate measurement - measures variation of flow within each breath (max, min, average) and is particularly suitable for breath-responsive blowers. Requires establishing correlation between filter flow and pressure drop across the filter system and uses a breathing machine for representative inhalation/exhalation cycles.
- Test setups: Procedures differ for Respiratory Interface class T (tight fitting) and class L (loose fitting); typical arrangements are provided for each, including where the device blower is integrated.
- Data correction and reporting: All volumetric flow rates are corrected to reference conditions (20 °C, 1013 hPa). Test reports must include measured values, conditions, and measurement uncertainty.
Applications and users
- RPD manufacturers validating blower-assisted filter performance and design choices (battery sizing, flow control).
- Test laboratories performing conformity testing against performance standards.
- Certification bodies and regulatory authorities assessing compliance for assisted filtering RPD.
- Occupational health and safety professionals selecting appropriate powered or assisted respirators for workplace risks.
Related standards
- ISO 16900 series (e.g., Part 1 inward leakage; Part 2 breathing resistance; Part 9 CO2 content)
- ISO 16972 (terms and definitions for RPD)
ISO 16900-8:2015 is essential when accurate, standardized measurement of delivered air flow is required to demonstrate device performance, safety and regulatory compliance for assisted filtering RPD.
