Overview
EN ISO 25139:2011 (ISO 25139:2011) specifies a manual method for determining methane (CH4) concentration in emissions from stationary sources using gas chromatography (GC). The method is defined as an independent measurement method (suitable for calibration/validation of automated systems) and is validated for mass concentrations up to 1 500 mg/m3. The standard covers sampling, analytical determination, calculation of results, and quality assurance/quality control (QA/QC) procedures.
Key topics and requirements
- Principle: Extract waste gas, collect a sample (bag, canister or direct loop) and analyze a subsample by GC after separation on packed or capillary columns; detection is typically by flame ionization detector (FID).
- Sampling system requirements: Heated sampling probe (stainless steel or glass), particle filter (quartz fibre/ceramic), sample gas cooler or dryer, flow meter, pumps, and gas-sampling vessel (bag, glass tube or canister). Short, condensation-free sampling lines are required.
- Analytical apparatus: Gas chromatograph with appropriate column type (packed or capillary/PLOT) and FID, calibrated with reference gases of known methane content.
- Performance characteristics: The standard addresses calibration, repeatability, limit of detection, uncertainty, and validated concentration range (up to 1 500 mg/m3).
- QA/QC procedures: Routine checks, frequency of calibrations, use of reference gases, and documentation requirements to ensure traceability and measurement reliability.
- Interferents and corrections: Identification and management of interfering substances and accounting for water vapour and oxygen when calculating methane mass concentration.
Applications and users
EN ISO 25139:2011 is used for:
- Emission monitoring and reporting of methane from stationary sources such as landfill vents, biogas plants, combustion processes and industrial stacks.
- Independent verification and calibration/validation of permanently installed automatic measuring systems (serves as a reference/standard method).
- Environmental laboratories, emission testing service providers, plant operators, regulatory agencies and QA/QC personnel who perform or audit methane measurements.
- Use cases include compliance testing, emissions inventories, performance checks of automated monitors, and research into source-specific methane releases.
Related standards
- ISO 9169 - performance characteristics of automatic measuring systems (referenced).
- EN 15267-3 - certification and performance criteria for automated emission monitoring systems (referenced).
- ISO 25140:2010 - related terminology and concepts for stationary source emissions (referenced).
- EN 14181 (mentioned contextually) - standard reference methods and SRM concepts for validation/certification.
Keywords: methane emissions, gas chromatography, EN ISO 25139, ISO 25139:2011, stationary source emissions, flame ionization detector, sampling system, QA/QC, independent measurement method.
