ISO 10849:2022

Overview

ISO 10849:2022 - "Stationary source emissions - Determination of the mass concentration of nitrogen oxides in flue gas - Performance characteristics of automated measuring systems" - defines how to measure NOx (NO and NO2) mass concentration in flue gas from stationary sources. It specifies the fundamental structure, performance characteristics, and validation principles for Automated Measuring Systems (AMS) used for continuous, permanently installed emissions monitoring. The standard covers both extractive and in situ (non‑extractive) systems and supports multiple analyser technologies (chemiluminescence, NDIR, FTIR, NDUV, DOAS, and equivalent laser spectroscopic methods) provided they meet the minimum performance requirements.

Key topics and technical requirements

• Scope and measurand: Defines NOx as NO + NO2 and scope for stationary source flue gas monitoring.
• Automated Measuring System (AMS) design: Structure of AMS, including analyser, sampling and sample‑conditioning systems (extractive vs in situ).
• Analytical techniques: Accepts CL, NDIR, FTIR, NDUV, DOAS and equivalent instrumental/laser methods.
• Performance characteristics: Specifies key metrics such as response time, transport time, converter efficiency (NO→NO2 when applicable), lack‑of‑fit (linearity), accuracy, period of unattended operation, and measurement uncertainty.
• Validation and performance tests: Procedures for initial performance tests and ongoing quality control; validation using reference materials or comparable methods.
• Sampling & installation: Guidance on sampling location, representative sampling, and calculation procedures (including conversion from volume to mass concentration).
• Quality assurance / QC: Frequency of checks, calibration, span gas use, validation against reference methods, and uncertainty evaluation.
• Supporting annexes: Practical examples and normative details in Annexes A–G (e.g., extractive/in situ system illustrations, NO→NO2 converter specs, operational gases, procedures for performance determination, example validation results, and uncertainty calculation).

Practical applications and users

ISO 10849:2022 is intended for:

• Environmental regulators setting or auditing continuous emissions monitoring requirements.
• Power plants, industrial facilities, and boiler operators implementing continuous NOx monitoring to comply with permits.
• Instrument manufacturers and system integrators designing and validating AMS hardware and software.
• Testing laboratories and QA/QC teams performing calibration, validation, and uncertainty assessments.
• Environmental consultants advising on selection, installation, and interpretation of NOx monitoring systems.

Related standards

• ISO 9169 (performance characteristics of AMS)
• ISO 14956 (evaluation of measurement procedures against required uncertainty)
• Other ISO standards on gas monitoring (referenced for harmonized QA/QC and uncertainty methods).

Keywords: ISO 10849:2022, NOx monitoring, automated measuring systems, flue gas, chemiluminescence, FTIR, in situ, extractive, performance characteristics, emissions monitoring, QA/QC, measurement uncertainty.