Overview
ISO 20264:2019 specifies a standardized FTIR spectrometry method for measuring the mass concentration of individual volatile organic compounds (VOCs) in waste gases from non-combustion stationary sources. The method supports continuous extractive monitoring from ducts and stacks, and also allows bag sampling where direct extractive sampling is impractical (provided VOCs do not adsorb on the bag material). The standard covers measurement principles, sampling, spectral acquisition and analysis, calibration, interference handling, QA/QC and key performance criteria for VOC measurement using FTIR.
Key topics and requirements
- Measurement principle: Use of Fourier Transform Infrared (FTIR) spectrometry - interferogram acquisition, fast Fourier transform (FFT) and application of Beer’s law for concentration quantification.
- Equipment: Specifications for sampling systems and analytical FTIR apparatus (gas cell path length, resolution and instrumental noise affect detection capability).
- Sampling methods: Extractive continuous sampling and bag sampling (conditional on compound stability and adsorption). Guidance on sampling locations and sample lines.
- Data quantification: Creation of calibration/reference spectra, analytical band selection, chemometric models for overlapping spectra, validation of models and residual checks.
- Calibration & verification: Use of calibration verification gas with known concentrations, zero checks, and procedures to assess repeatability and lack-of-fit.
- Performance criteria: Requirements for response time, limit of detection (LOD) considerations, losses/leakage control in sampling lines, and uncertainty evaluation. Note: practical LOD depends on instrument parameters and interferences (e.g., water vapour, CO2).
- QA/QC procedures: Routine validation, calibration verification, background (zero) measurement and documentation to ensure reliable VOC concentration results.
- Annex guidance: Normative and informative annexes address FTIR performance parameters, typical VOC spectral features, band selection and validation examples.
Applications and users
ISO 20264:2019 is intended for:
- Environmental and air quality laboratories performing VOC emission testing
- Industrial operators (painting, printing, chemical manufacturing, solvent use) monitoring waste gas VOCs
- Emissions monitoring service providers and consultants
- Regulatory agencies and compliance auditors requiring standardized VOC measurement methods
- Instrument manufacturers and system integrators developing FTIR-based emissions monitors
Practical applications include continuous emissions monitoring, process emissions characterization, compliance testing, and source apportionment where individual VOC speciation (not just total VOCs) is required for risk assessment and regulatory reporting.
Related standards
- Relevant ISO air quality and stationary source emissions standards and guidance produced by ISO/TC 146 (Air quality).
- Guidance documents on FTIR measurement principles, calibration best practices and uncertainty evaluation used alongside ISO 20264:2019 for robust VOC monitoring.
Keywords: ISO 20264:2019, FTIR spectrometry, VOC measurement, stationary source emissions, waste gas monitoring, bag sampling, QA/QC, calibration, limit of detection.