ISO 11042-2:1996

Overview

ISO 11042-2:1996 - "Gas turbines - Exhaust gas emission - Part 2: Automated emission monitoring" defines requirements for continuous, automated monitoring of gas turbine exhaust emissions. The standard establishes a monitoring programme and the selection, installation and operation of hardware for continuous gas emission measurements. It specifies what must be measured, sampling principles, analyser components, data recording and quality assurance (calibration, functional checks, drift and relative‑accuracy tests).

Key topics and technical requirements

• Mandatory continuous parameters: emissions, diluent gases (O2, CO2), exhaust gas flow (calculated or measured), fuel consumption and gas turbine performance. Periodic chemical fuel analysis from samples is required.
• Monitoring system architecture: sampling (extractive and non‑extractive), analysers, data acquisition/recording and an electronic evaluation system to produce daily, monthly and annual reports.
• Sampling methods: extractive sampling with conditioning (filters, heating, pumps) and non‑extractive (in‑stack) point and path measurements (examples illustrated in the standard).
• Measurement locations: guidance for probe placement for gaseous emissions, particulates and reference measurements to ensure representativeness.
• Data handling and outputs: conversion to standard conditions, plausibility checks, status signals, averaging and classification (compliance/ exceedance), and storage timelines (daily data, monthly, annual summaries).
• Quality assurance and maintenance: calibration function requirements, functional checking, supply/use of calibration gases, drift and span tests, relative accuracy tests and maintenance procedures to ensure data validity.
• Applicability: open‑cycle gas turbines and as a basis for semi‑closed cycles, marine applications and turbines used for shaft power or electrical generation (excludes aircraft applications). Not intended for formal acceptance testing unless agreed by parties.

Practical applications and who uses it

ISO 11042-2 is used to design, select and operate automated emission monitoring systems (CEMS) for gas turbine installations in power plants, industrial facilities and marine propulsion where continuous emissions monitoring is required for regulatory compliance, environmental reporting, performance diagnostics and process control. Primary users:

• Plant engineers and emissions compliance teams
• Environmental monitoring contractors and system integrators
• Instrumentation and control engineers specifying analysers and sampling systems
• Regulatory bodies and auditors specifying monitoring programmes

Related standards

• ISO 11042-1 (Measurement and evaluation)
• ISO 2314 (gas turbine test methods)
• ISO 4225, ISO 6879, ISO 7504, ISO 10396 (vocabulary, performance characteristics, sampling and analysis guidance)

Keywords: ISO 11042-2, gas turbine emissions, automated emission monitoring, continuous gas emission measurements, exhaust gas monitoring, CEMS, extractive sampling, non‑extractive sampling, analyser calibration.