🏭 Carbon dioxide, carbon monoxide and oxygen in flue gas — automated measuring systems, ISO 12039

Environment ISO 12039

Overview

WHAT THE DOCUMENT SPECIFIES (clause 1 of ISO 12039:2019): the basic structure and the most important performance characteristics of automated measuring systems (AMS) for carbon monoxide (CO), carbon dioxide (CO2) and oxygen (O2) in emissions from stationary sources, as well as methods and equipment for measuring the concentrations of these gases. The method allows continuous monitoring with permanently installed stationary systems. It describes extractive and in-situ systems with analysers working, among others, on the principle of infrared absorption (CO and CO2), paramagnetism (O2), zirconium oxide (O2), the electrochemical cell (O2) and tunable laser spectroscopy — TLS (CO, CO2 and O2). Other instrumental methods are permitted if they meet the minimum requirements of the document. The introduction explains why these three gases are measured together: besides demonstrating compliance with regulations, the determination of O2 or CO2 is needed to convert the measured concentrations of other pollutants to reference conditions.

THERE IS NO POLISH STANDARD. A search for "12039" in the PKN catalogue (25.09.2026) returns only other documents with this number: PN-B-12039 (1954, 1989) and PN-EN 12039 (2001, 2016-07) — the latter concerns flexible sheets for waterproofing and the determination of adhesion of granules. Laboratories therefore cite the ISO document directly. One entry in the database of scopes has "PN-EN 12039" next to "Przyczepności posypki" [adhesion of granules] — this is a different standard, and the coincidence of numbers must not be taken as a citation of this method.

STATUS AT THE PUBLISHER (ISO website, reading of 25.09.2026): ISO 12039:2019 — published 2019-10, edition 2, 52 pages, ISO/TC 146/SC 1; "This publication was last reviewed and confirmed in 2025. Therefore this version remains current." According to the foreword, the second edition replaced ISO 12039:2001: the TLS technique for in-situ measurements was added, the performance characteristics and criteria and the QA/QC procedures were changed for consistency with newer ISO standards, and examples of test results and uncertainty calculations for CO, CO2 and O2 were added.

PERFORMANCE CHARACTERISTICS OF AMS AND THEIR CRITERIA (Table 1, 7.1). The percentages for CO and CO2 refer to the UPPER LIMIT OF THE LOWEST MEASURING RANGE USED, for O2 — to the volume concentration of oxygen: • response time ≤ 200 s (CO, CO2 and O2); • repeatability standard deviation at zero and at the span point ≤ 2.0 % (O2 ≤ 0.2 %); • lack of fit (linearity) ≤ 2.0 % (O2 ≤ 0.2 %); • zero and span drift within 24 h ≤ 2.0 % (O2 ≤ 0.2 %), over the unattended operation period ≤ 3.0 % (O2 ≤ 0.2 %); • sensitivity to sample gas pressure for a change of 2 kPa ≤ 3.0 %, to sample gas flow (extractive AMS) ≤ 2.0 %, to ambient temperature for a change of 10 K ≤ 3.0 % (O2 ≤ 0.3 %), to supply voltage per 10 V ≤ 2.0 % (O2 ≤ 0.2 %); • cross-sensitivity ≤ 4.0 % (O2 ≤ 0.4 %); • losses and leakage in the sampling line ≤ 2.0 % of the measured value. The upper limit of the lowest range is chosen so that the measured values lie between 20 % and 80 % of the range. The uncertainty of the AMS is calculated according to ISO 14956 from the characteristics of the test; the uncertainty in the field is established by the user (e.g. by the direct or indirect approach according to ISO 20988) and it also covers the sampling line, the site conditions and the reference gases (7.2).

EXTRACTIVE AND IN-SITU SYSTEMS (6.1). In an extractive system the gas is taken with a probe and led through the sampling line and the conditioning system to the analyser; three types — "cold-dry", "hot-wet" and with dilution — are described in ISO 10396. An in-situ system measures directly in the duct or stack, without gas preparation.

CONVERSION OF THE RESULT (clause 8). The concentration measured in wet gas is converted to standard conditions (273.15 K; 101.325 kPa) with a formula using the gas temperature and pressure, and to dry gas — additionally using the water vapour content. A result without stated reference conditions cannot be compared with a limit value expressed under those conditions.

HOW ACCREDITATION SCOPES CITE THE DOCUMENT. Measurement of 25.09.2026 on the database of PL accreditation scopes (1310 laboratories with entries): 45 entries at 19 laboratories with a notation beginning with "ISO 12039" — most often "ISO 12039:2019" (39), also "ISO 12039:2019-10" (2). Object: "Gazy odlotowe" [flue gases] (36) and "Automatyczne Systemy Monitoringu (AMS)" [automated monitoring systems (AMS)] (9) — in the latter entries the object tested is the measuring system itself. Methodology: in 44 of the 45 entries carbon dioxide alone ("Stężenie CO2" [CO2 concentration], "Stężenie dwutlenku węgla" [carbon dioxide concentration], "Emisja CO2 (z obliczeń)" [CO2 emission (calculated)]), in one CO2 together with O2. Technique: NDIR (non-dispersive infrared spectrometry). The declared CO2 ranges lie between 0.03 % and 40 % by volume, most often "(1 - 22) %". Next to it stands PN-ISO 10396:2001 (10 notations) or ISO 10396:2007 (3) — a document on sampling for the automated determination of gas concentrations. NOTE: PN-ISO 10396:2001 (Polish-language version, implemented ISO 10396:1993) was WITHDRAWN by PKN on 15-11-2022, and the card indicates no successor; the catalogue has no other PN standard with this number (search "10396", 25.09.2026). WHY ALMOST ONLY CO2: for carbon monoxide in flue gas the scopes most often cite PN-EN 15058 and PN-ISO 10396, for oxygen — PN-ISO 10396 and PN-EN 14789 (measurement on the same database: entries with the object "gazy"/"emisja" [gases/emission] and a methodology on carbon monoxide or oxygen). The editions in force, PN-EN 15058:2017-04 and PN-EN 14789:2017-04, have the words "standardowa metoda odniesienia" [standard reference method] in their titles — for CO (non-dispersive infrared spectrometry) and for oxygen (paramagnetism); both cards have no "Withdrawn" header (25.09.2026). For carbon dioxide this place in the scopes is taken by ISO 12039.

THE KEY OF THE "LABORATORIES" TAB: "ISO 12039" — 19 laboratories and 45 entries, without any foreign entries (the standard PN-EN 12039 begins differently and does not fall under the key).

WHAT WE DO NOT GIVE. The extract of ISO 12039:2019 made available by the publisher reaches 9.1 (introduction to QA/QC). WE DO NOT HAVE Table 2 with the frequency of checks during operation, the procedures for testing the performance characteristics (Annex E, normative), the descriptions of the analytical methods (Annexes A–C) or the examples of uncertainty calculation (Annex G). We do not give the measuring ranges in which the systems "have been used successfully" (reference from clause 1 to Annex G).

Method principle

The flue gas is taken from the duct with a probe and led through the sampling line and the conditioning system (cold-dry, hot-wet or with dilution) to the analyser — or it is measured directly in the duct with an in-situ system. CO and CO2 are most often determined by infrared absorption (NDIR), O2 by the paramagnetic method, with a zirconia or an electrochemical sensor; all three gases can be measured by laser spectroscopy (TLS). The system must meet the criteria for the performance characteristics of Table 1, and the result is converted to standard conditions and dry gas.

Applications

• Measurements of the concentration and emission of CO2 in flue gas from combustion plants — PL accreditation scopes
• Testing and checking of automated emission monitoring systems (AMS)
• Determination of O2 and CO2 for converting the concentrations of other pollutants to reference conditions
• Optimisation of the combustion process (introduction of the document)

Key parameters

Standard

Standard number

ISO 12039:2019 (wydanie drugie, 2019-10; bez polskiej normy wprowadzającej)

Title (PL)

Emisja ze źródeł stacjonarnych — Oznaczanie masowego stężenia tlenku węgla, dwutlenku węgla i tlenu w gazach odlotowych — Charakterystyki automatycznych systemów pomiarowych (tłumaczenie robocze — polskiej normy nie ma)

Title (EN)

Stationary source emissions — Determination of the mass concentration of carbon monoxide, carbon dioxide and oxygen in flue gas — Performance characteristics of automated measuring systems

Step-by-step procedure

1. Survey of the source

   Before the measurements establish: the range of ambient and gas temperature, the water vapour content, the dust load, the expected concentrations of CO, CO2 and O2 and of interfering substances (8.1).

2. Choice of system

   Extractive (cold-dry, hot-wet, with dilution) or in situ; measuring range such that the results lie within 20–80 % of the range.

3. Performance characteristics of the system

   The values determined in the test (Annex E) must meet the criteria of Table 1; uncertainty calculated according to ISO 14956.

4. Measurement

   Gas taken with a probe and prepared in the conditioning system, or in-situ measurement at a representative point of the stack.

5. Conversion of the result

   To standard conditions (273.15 K; 101.325 kPa) and — if necessary — to dry gas (clause 8).

6. Quality control during operation

   Checking of selected performance characteristics at the frequency of Table 2 (we do not give the table); the QA/QC results are documented (9.1).

Required equipment and apparatus

Reagents, media and consumables

Health and safety (OHS)

• Work on stack measurement platforms — protection against falls from height
• Carbon monoxide in flue gas — CO detector at the station, ventilation at the conditioning system
• Hot probes and heated lines — thermal gloves
• Reference gas cylinders — fastening and protection against falling over

Frequently asked questions