Overview
ISO 12569:2017 - "Thermal performance of buildings and materials - Determination of specific airflow rate in buildings - Tracer gas dilution method" defines internationally‑recognised procedures to measure the ventilation rate or specific airflow rate of a building space (treated as a single zone) using a tracer gas. The standard describes when tracer‑gas techniques are applicable (requirements for concentration uniformity, exhaust measurement, effective mixed zone and ventilation stability) and gives procedural, apparatus and reporting guidance for valid measurements.
Key topics and technical requirements
- Measurement methods: ISO 12569:2017 provides three tracer‑gas approaches:
- Concentration decay method (two‑point, multi‑point, pulse and step‑down variants)
- Continuous dose method (average inverse concentration, average concentration, stationary concentration)
- Constant concentration method
- Definitions: Key terms include single zone, effective mixed zone (Vemz), ventilation rate (Qv) and specific airflow rate (N).
- Measurement apparatus: Requirements and guidance for tracer gas dosing devices, sampling apparatus and gas analysers (including calibration, resolution and drift considerations).
- Procedure and data processing: Building preparation, ancillary measurements, specific step‑by‑step procedures for each method and calculation formulas for deriving ventilation and specific airflow rates.
- Accuracy and uncertainty: Guidance on sources of error (room concentration distribution, sampling/storage, analyser accuracy), calibration, and methods to estimate confidence intervals and propagate errors.
- Reporting: Minimum test report content: identification, HVAC details, test conditions, apparatus, collected data and results, and test date.
- Informative annexes: Practical guidance on special issues such as large spaces, effects of temperature/wind changes, simultaneous estimation of Q and Vemz, and error‑minimizing techniques.
Practical applications
- Verifying ventilation system performance and compliance with design/intended rates
- Quantifying outdoor‑air exchange for indoor air quality (IAQ) assessments and contaminant dilution studies
- Supporting energy‑efficiency and building commissioning by measuring actual airflow and detecting under‑ or over‑ventilation
- Research and field testing of HVAC systems, pollutant source strength estimation and retrofit evaluation
Who should use this standard
- HVAC and ventilation engineers
- Building performance and commissioning professionals
- Indoor air quality specialists and environmental consultants
- Energy auditors and researchers conducting field measurements
- Regulatory authorities and test labs specifying or verifying ventilation performance
Related standards and context
- Published by ISO/TC 163 (Thermal performance and energy use in the built environment). This third edition replaces ISO 12569:2012 and aligns with other ISO guidance on building thermal performance and test methods. For formal application, follow calibration and measurement traceability practices referenced in national and laboratory accreditation schemes.
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