EN ISO 23874:2018 PDF

Overview

EN ISO 23874:2018 (ISO 23874:2006 adopted by CEN) specifies gas‑chromatographic performance requirements for determining the composition of treated natural gas so that the hydrocarbon dewpoint can be calculated reliably using an appropriate equation of state. It applies to gases with maximum dewpoint temperatures (cricondentherms) between 0 °C and −50 °C and for pressures where those maxima occur (approximately 2–5 MPa / 20–50 bar). The procedure covers hydrocarbon measurement in the C5–C12 range with n‑pentane used as a bridge component and major components measured in accordance with ISO 6974.

Key topics and technical requirements

• Scope: analysis sufficient to calculate hydrocarbon dewpoint (phase boundary) for transmission/pipeline quality natural gas.
• Component coverage: major components (N2, CO2, C1–C5 and up to C12) per ISO 6974 (all parts); higher hydrocarbons handled as fractions by carbon number.
• Hydrocarbon range: measurement and treatment of hydrocarbons from C5 to C12 (n‑pentane as calibration bridge; C6+ measured relative to n‑pentane).
• Performance requirements for higher hydrocarbons:
  • Capable of measuring alkanes up to n‑dodecane.
  • Sensitivity for individual alkanes down to 1×10−7 mole fraction (0.1 ppm) or better.
  • Resolve and quantify benzene, toluene, cyclohexane, methylcyclohexane individually.
  • Use detectors with predictable response proportional to mass or carbon content (typically FID).
  • Separation and temperature programming such that boiling points of unidentified peaks can be interpolated between n‑alkanes.
• Reference materials: recommends certified reference mixtures for major components (CRM1) and for higher hydrocarbons (CRM2) including n‑pentane through n‑octane (ideally up to n‑dodecane).
• Includes guidance on sampling, uncertainty estimation and dewpoint calculation inputs.

Practical applications and users

• Pipeline and transmission system operators performing hydrocarbon dewpoint control and specification compliance.
• Industrial and third‑party gas analysis laboratories validating chromatographic systems for pipeline gas.
• Instrument and analyzer manufacturers designing gas chromatographs and detectors for natural gas analysis.
• Regulatory bodies, quality assurance teams, and contract laboratories assessing risk of hydrocarbon condensation and ensuring safe, dry gas delivery.

Related standards

• ISO 6974 (Parts 1–6) - Determination of natural gas composition by gas chromatography (referenced for major components).
• ISO 6975 - Extended gas chromatographic analysis.
• ISO 10715 - Natural gas sampling guidelines.

EN ISO 23874:2018 is essential for consistent, traceable hydrocarbon dewpoint calculations using gas chromatography, improving safety, compliance and operational decision‑making in natural gas transmission and processing.