Overview
ISO 10101-2:2022 defines a volumetric Karl Fischer procedure for determining water in natural gas. It specifies how to sample, absorb and titrate gas volumes (expressed in m3 at 273.15 K and 101.325 kPa) and applies to water concentrations from 5 mg/m3 to 5 000 mg/m3. The standard covers reagent and absorbent preparation, apparatus, standardization, procedure, expression of results, uncertainty and reporting. A safety warning highlights that local hazardous‑area regulations must be observed.
Key topics and technical requirements
- Scope and units: Volumes referenced at 0 °C and 1 atm; applicable water range 5–5 000 mg/m3 (Clause 1).
- Principle: Gas is passed through an absorbent solution; extracted water is titrated by Karl Fischer (KF) reagent (Clause 4).
- Reagents: KF reagent (approx. 5 mg/ml water equivalent); solvent options include dry methanol or 2‑methoxyethanol; components such as imidazole, sulfur dioxide, iodine and absorbent (ethylene glycol based) are specified (Clause 5).
- Apparatus: Typical items include a Karl Fischer titrator, wet‑test gas meter (±1% accuracy), guard tube/Durand bottle with drying agent, titration cell and syringes (Clauses 6, Annex A).
- Standardization: Daily (or before use) determination of reagent water equivalent using small, known water additions (10 µl syringe) and calculation T = mass of water (mg) ÷ reagent volume used (ml) (Clause 7).
- Sampling & procedure: Follow ISO 10101‑1 sampling practice; procedures cover cell preparation, purging/flow considerations, and differences for laboratory vs. field use (Clauses 8–9).
- Results & quality: Calculation method, measurement uncertainty (Clause 10.2) and mandatory test report content (Clause 11).
Practical applications and users
ISO 10101‑2 is intended for:
- Analytical laboratories and field technicians performing moisture determinations on natural gas.
- Gas producers, pipeline operators and distribution companies monitoring gas quality and pipeline integrity.
- Quality assurance teams and custody‑transfer operations requiring verified moisture measurements.
- Engineers commissioning dehydration systems or troubleshooting moisture ingress.
Typical uses:
- Routine moisture monitoring for safety and corrosion prevention.
- Compliance testing and specification verification.
- Calibration and verification of dehydration or gas conditioning equipment.
Related standards
- ISO 10101‑1 - Natural gas: Karl Fischer method introduction and principles (sampling reference).
- ISO 383 - Laboratory glassware (ground joints).
- ISO 14532 - Natural gas vocabulary.
- ISO 10101 series (other parts) for complementary guidance.
Keywords: ISO 10101-2:2022, Karl Fischer, natural gas water determination, volumetric procedure, moisture analysis, water content mg/m3, gas sampling, titration cell.
Open preview (PDF)Natural gas — Determination of water by the Karl Fischer method — Part 2: Volumetric procedure