Overview - EN ISO 10101-3:2022 (Natural gas, Karl Fischer coulometric)
EN ISO 10101-3:2022 specifies a coulometric Karl Fischer (KF) procedure for the determination of water content in natural gas and other gases that do not react with KF reagents. The method covers water concentrations from 5 mg/m3 to 5 000 mg/m3 and expresses gas volumes at 273.15 K (0 °C) and 101.325 kPa (1 atm). The standard is the CEN-adopted version of ISO 10101-3:2022 and supersedes earlier editions.
Key topics and technical requirements
- Principle: Water in a measured gas volume is absorbed into the KF titration cell and reacted with iodine generated electrolytically; the electrical charge passed is proportional to water mass (coulometry is an absolute method).
- Measurement range: Applicable for 5–5 000 mg/m3 water in natural gas.
- Cell design: Covers both diaphragm and diaphragm‑free coulometric cells and discusses advantages and limitations of each design.
- Reagents: Specially formulated coulometric reagents are used; because coulometry is absolute, the reagent does not require standardization.
- Apparatus and sampling: Requirements for titration cells, electrodes, gas inlet (glass frit), and sealed sampling to avoid moisture ingress are specified.
- Procedure elements: Installation, response testing, measurement, and blank-value determination are detailed.
- Results and reporting: Calculation method, expression of results, measurement uncertainty, and required test report content are included.
- Safety and scope limits: Notes on placement in hazardous areas and applicability only to gases that do not chemically react with KF reagents.
Applications and who uses this standard
This standard is used wherever precise measurement of moisture in gases is required, including:
- Natural gas producers and processors monitoring gas quality and conditioning processes.
- Transmission and distribution operators for quality control and pipeline integrity management.
- Analytical laboratories performing KF coulometric moisture analysis on gas samples.
- Manufacturers of KF coulometers and sampling systems for instrument design and compliance.
- Regulatory and compliance bodies specifying gas quality tests.
Practical uses include routine moisture monitoring, quality control of supply streams, acceptance testing, and laboratory method standardization.
Related standards
Keywords: EN ISO 10101-3:2022, natural gas water determination, Karl Fischer coulometric, KF coulometer, water content measurement, gas sampling, measurement uncertainty.
