SIST EN ISO 6974-2:2012

Name: SIST EN ISO 6974-2:2012 — Natural gas - Determination of composition and associated uncertainty by gas chromatography - Part 2: Uncertainty calculations (ISO 6974-2:2012)
SKU: SIST EN ISO 6974-2:2012
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Natural gas - Determination of composition and associated uncertainty by gas chromatography - Part 2: Uncertainty calculations (ISO 6974-2:2012)

Название (английский):

Natural gas - Determination of composition and associated uncertainty by gas chromatography - Part 2: Uncertainty calculations (ISO 6974-2:2012)

Статус документа:: Действующий
Формат:: Электронный (PDF)
Количество страниц:: 24
Дата публикации:: 13 июня 2012 г.
ICS:: 75.060
Технический комитет:: NAD - Petroleum products, lubricants and related products

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Описание (английский):

This part of ISO 6974 describes the process required to determine the uncertainty associated with the mole fraction for each component from a natural gas analysis in accordance with ISO 6974‑1.

Abstract

Похожие стандарты

Стандарты, упомянутые в описании

Overview

EN ISO 6974-2:2012 (ISO 6974-2:2012) specifies how to calculate the measurement uncertainty associated with component mole fractions determined by gas chromatography in natural gas. Intended to be used together with ISO 6974-1 (general guidelines and composition calculation) and the analysis methods in ISO 6974-3 and subsequent parts, this part (Part 2) covers the formal uncertainty-calculation steps required after a chromatographic analysis has produced raw and processed mole fractions.

Key points:

Focuses on uncertainty calculations for mole fractions of natural-gas components.

Implements uncertainty assessment in accordance with ISO/IEC Guide 98-3 (GUM).

Complements the analysis workflow in ISO 6974-1 by covering Steps 9 and 10 (calculation of standard and expanded uncertainties).

Key Topics and Requirements

Scope: Defines the process to determine uncertainty for each gas component’s mole fraction following ISO 6974‑1 procedures.

Normative references: ISO 6974-1:2012 and ISO/IEC Guide 98-3 (GUM).

Analysis types: Distinguishes uncertainty contributions for Type 1 and Type 2 analyses (as defined in ISO 6974-1), addressing random and systematic sources.

Uncertainty sources: Includes uncertainty of certified reference mixtures, analytical measurement uncertainty, and uncertainty from data fitting (regression).

Methods and alternatives:

Conventional normalization (noted as conservative for some methods).
Generalized least squares (GLS) normalization (annexed in ISO 6974-1) for improved uncertainty assessment.
Methane-by-difference approach (Annex A) and alternative calculations (Annex C).
Treatment of relative response factors (Annex B).

Symbols and definitions: Standardized symbols (u(), U(), x*, x, response factors, etc.) for consistent reporting.

Applications and Users

EN ISO 6974-2:2012 is used by organizations requiring robust uncertainty quantification for natural gas composition, including:

Analytical laboratories performing gas-chromatographic composition analyses.

Calibration and reference-gas producers.

Gas transmission and distribution companies for custody transfer, billing, and quality reporting.

Instrument manufacturers and validation engineers designing GC systems.

Regulators and auditors assessing measurement traceability and conformity. Practical applications include providing uncertainty inputs for calorific value calculations, physical-property modelling, and compliant reporting of gas composition in contractual and regulatory contexts.

Related Standards

ISO 6974-1:2012 - General guidelines and calculation of composition (mandatory companion).

ISO/IEC Guide 98-3 (GUM) - Guide to the expression of uncertainty in measurement.

ISO 6974 series (Parts 3–6) - Specific GC methods and component scopes referenced for analysis procedures.

Keywords: ISO 6974-2, EN ISO 6974-2:2012, natural gas, gas chromatography, uncertainty calculations, mole fraction, GUM, calibration, methane-by-difference, generalized least squares.

SIST EN ISO 6974-2:2012

Abstract

Похожие стандарты

Overview

Key Topics and Requirements

Applications and Users

Related Standards

Технические детали

ISO 6974-2:2012

Natural gas — Determination of composition and associated uncertainty by gas chromatography — Part 2: Uncerta…

ISO 6974-1:2012

Natural gas — Determination of composition and associated uncertainty by gas chromatography — Part 1: General…

SIST EN ISO 6974-1:2012/AC:2013

Natural gas - Determination of composition and associated uncertainty by gas chromatography - Part 1: General…

SIST EN ISO 6974-3:2019

Natural gas - Determination of composition and associated uncertainty by gas chromatography - Part 3: Precisi…