ISO 6974-5-2014 PDF

Full title and description

Natural gas — Determination of composition and associated uncertainty by gas chromatography — Part 5: Isothermal method for nitrogen, carbon dioxide, C1 to C5 hydrocarbons and C6+ hydrocarbons. This part of ISO 6974 specifies an isothermal gas‑chromatographic procedure for quantifying N2, CO2, individual C1–C5 hydrocarbons and a composite C6+ fraction in natural gas samples.

Abstract

ISO 6974-5:2014 defines an isothermal GC method, required apparatus and configuration, procedural steps, expression of results and guidance on associated uncertainty for determination of the listed components and the composite C6+ group. Informative annexes give examples of application and practical setup guidance (valve timings, restrictor settings).

General information

• Status: Published / Current (confirmed at ISO five‑year review).
• Publication date: July 2014 (Edition 2, 2014 — ISO catalogue shows publication in July 2014).
• Publisher: International Organization for Standardization (ISO); available also as EN/EN‑ISO national adoptions.
• ICS / categories: 75.060 (Natural gas).
• Edition / version: Edition 2 (2014).
• Number of pages: 24 (official ISO edition — published booklet length).

Scope

This part of ISO 6974 applies to analysis of natural gas samples to determine mole fractions of nitrogen, carbon dioxide, methane through pentane (C1–C5) individually, and to determine a composite measurement for all hydrocarbons of carbon number 6 and above (C6+). It is applicable where component concentrations fall within the working ranges specified in the standard and is intended for laboratory and on‑line process applications using an isothermal GC arrangement.

Key topics and requirements

• Isothermal gas‑chromatographic method for N2, CO2, C1–C5 and composite C6+ determination.
• Specification of required materials, apparatus and column/detector configurations (TCD/FID arrangements and valve timing/setup guidance in informative annexes).
• Procedural steps for sample introduction, chromatographic separation and peak measurement under isothermal conditions.
• Expression of results: reporting of component mole fractions and the C6+ composite, and instructions for calculating associated uncertainty.
• Guidance examples (informative annexes) and practical setup notes for valve timings and restrictor settings to assist reproducible implementation.

Typical use and users

Used by natural gas analytical laboratories, pipeline and distribution operators, custody transfer and commercial metering laboratories, instrument manufacturers (GC vendors), calibration gas suppliers, and national metrology and regulatory bodies for quality control, billing calculations, calorific value inputs and compliance testing. Typical users implement the method for routine composition reports and as part of a measurement chain feeding calculation standards (e.g., calorific value, density, Wobbe index).

Related standards

ISO 6974‑5:2014 is part of the ISO 6974 series on natural gas analysis (see ISO 6974‑1, ‑2, ‑3, ‑4 (under revision / DIS stages), ‑6, etc.). It is commonly used alongside ISO 6976 (calculation of calorific value and related properties) and other parts of ISO 6974 that cover alternate chromatographic methods, uncertainty calculation and guidance on gas analysis. National and EN adoptions (EN ISO 6974‑5:2014 and identical national versions) exist.

Keywords

natural gas, gas chromatography, isothermal method, composition analysis, nitrogen, carbon dioxide, C1–C5 hydrocarbons, C6+, uncertainty, ISO 6974, custody transfer, calorific value input.

FAQ

Q: What is this standard?

A: ISO 6974‑5:2014 is an international standard specifying an isothermal gas chromatographic method to determine the composition of natural gas—specifically N2, CO2, individual C1–C5 hydrocarbons and a composite C6+ fraction.

Q: What does it cover?

A: It covers required materials and apparatus, chromatographic configuration, procedural steps, expression of results, and guidance on estimating associated uncertainty. Informative annexes provide setup examples and practical advice for valve timing and restrictor settings.

Q: Who typically uses it?

A: Gas analysis laboratories, pipeline and distribution operators, custody transfer labs, GC instrument vendors and calibration gas suppliers, and regulatory/metrology organizations involved in natural gas quality and commercial measurement.

Q: Is it current or superseded?

A: ISO 6974‑5:2014 (Edition 2) replaced the 2000 edition and is published/current; ISO indicates it was reviewed/confirmed (standard review cycle) and may be subject to revision activities of the ISO 6974 series. Users should check national adopters for any local amendments or later revisions.

Q: Is it part of a series?

A: Yes — it is Part 5 of the ISO 6974 series (other parts cover general guidelines, uncertainty calculation, alternate chromatographic methods, guidance for gas analysis and additional column arrangements). The parts are intended to be used together for full composition determination and uncertainty assessment.

Q: What are the key keywords?

A: Natural gas, gas chromatography (GC), isothermal GC, N2, CO2, hydrocarbons C1–C5, C6+ composite, composition, uncertainty, ISO 6974, calorific value input.