Overview
EN ISO 21258:2010 specifies a reference method for measuring the mass concentration of dinitrogen monoxide (N2O / nitrous oxide) in flue gas from ducts and stacks. The standard defines the non-dispersive infrared (NDIR) analytical technique and the associated sampling system and sample gas conditioning required for reliable N2O emissions measurement. EN ISO 21258:2010 is intended as a reference method for periodic monitoring and for calibration, adjustment or control of automatic monitoring systems (AMS) permanently installed on a stack. The method has been validated in practical conditions (e.g., sewage sludge incinerator testing with N2O up to about 200 mg/m3).
Key Topics
- Scope and principle: Defines the measurand (mass concentration of N2O) and the NDIR measurement principle for stationary source emissions.
- Sampling system requirements: Specifies sampling location, sampling points and sample-line components to obtain representative stack gas samples.
- Sample conditioning: Details conditioning to remove condensate and particulates and to maintain sample integrity before analysis.
- Analyser equipment (NDIR): Requirements for analyser set-up, calibration with reference gases, and on-site configuration.
- Performance criteria: Defines performance characteristics and procedures to determine measurement performance and measurement uncertainty in line with ISO guidance.
- Quality control and verification: Ongoing QC checks, frequency of tests, leak tests and field evaluation procedures to ensure data reliability.
- Reporting: Rules for expression of results and required content of test reports.
- Annexes: Practical aids including schematic analyser diagrams, test procedures for performance characteristics, example compliance assessments and leak test procedures.
Applications and Users
EN ISO 21258:2010 is aimed at professionals involved in stationary source emissions monitoring:
- Environmental laboratories performing stack gas analysis
- Plant operators and environmental compliance teams (power plants, waste incineration, industrial boilers)
- Manufacturers and integrators of automatic monitoring systems (AMS) using NDIR technology
- Regulatory authorities and consultants conducting periodic emissions monitoring and system calibration
Practical uses include periodic compliance monitoring, calibration and adjustment of permanent AMS, validation of emission inventories, and supporting greenhouse-gas reporting where accurate N2O measurements are required.
Related Standards
Important normative references that support EN ISO 21258:2010:
- ISO 9169:2006 - performance characteristics of automatic measuring systems
- ISO 14956 - evaluating suitability of measurement procedures vs required measurement uncertainty
- ISO/IEC Guide 98‑3:2008 (GUM) - Guide to the expression of uncertainty in measurement
Keywords: EN ISO 21258:2010, N2O emissions measurement, dinitrogen monoxide, non-dispersive infrared (NDIR), stack monitoring, reference method, sampling and conditioning, measurement uncertainty.