GOST 31369-2008 PDF

Full title and description

GOST 31369-2008 — "Natural gas. Calculation of calorific values, density, relative density and Wobbe index from composition" (Русское название: «Газ природный. Вычисление теплоты сгорания, плотности, относительной плотности и числа Воббе на основе компонентного состава»). Стандарт описывает методы вычисления основных физико‑химических показателей качества природного газа и других горючих газообразных топлив на основании известного компонентного состава.

Abstract

Standard GOST 31369‑2008 specifies algorithms and recommended data for calculating higher and lower calorific values, gas density, relative density and the Wobbe index from a gas component composition (molar or mass fractions). It also includes procedures for estimating the uncertainty of calculated values and contains informative and normative appendices (computer implementation notes, conversion coefficients, reference molar heats of combustion, and uncertainty/accuracy requirements for component analysis).

General information

• Status: Withdrawn / replaced by a revised edition (GOST 31369‑2021) in later catalogues.
• Publication date: Adopted 2008 (approved 06 June 2008); introduced/implemented 01 January 2010 in the Russian system (date of entry into force commonly shown as 01.01.2010).
• Publisher: Interstate Council on Standardization, Metrology and Certification / Federal Agency for Technical Regulation and Metrology (Rosstandart); original developer: VNIIM (D. I. Mendeleev Institute).
• ICS / categories: 75.060 (Extraction and processing of oil, gas and related products — Natural gas).
• Edition / version: GOST 31369‑2008 (original 2008 edition); later superseded by GOST 31369‑2021 in catalogues.
• Number of pages: 58 (typical PDF/published pagination).

Scope

Applies to physical and physico‑chemical quality indicators of natural gas and establishes calculation methods for higher and lower calorific values, density, relative density and the Wobbe index based on known component composition. Methods using molar or mass fractions are applicable for arbitrary compositions; methods using volumetric (volume) fractions are explicitly limited to gases composed mainly of methane (molar fraction of methane ≥ 0.50). The standard provides guidance for using published thermophysical data of pure components and for propagating uncertainty from component analysis to calculated properties.

Key topics and requirements

• Algorithms for calculation of higher and lower calorific values (molar and mass‑based formulations).
• Calculation methods for absolute density and relative density (to air) from composition and reference component data.
• Definition and calculation of the Wobbe index from calorific value and specific gravity.
• Recommended reference values for component properties (molar heats, molecular masses, compressibility considerations).
• Procedures and appendices for uncertainty estimation and required accuracy of component analysis (normative requirements for uncertainty propagation).
• Guidance for computer implementation and conversion coefficients for different standard reference temperatures.

Typical use and users

Used by natural gas producers, transmission and distribution companies, custody transfer and metering engineers, gas analysis laboratories, metrology institutes, regulatory authorities and software developers implementing gas quality calculators. Typical applications include gas quality reporting, billing/custody transfer calculations, specification compliance checks, and research or design work where derived thermophysical properties are required from chromatographic composition data.

Related standards

Closely related to the GOST series on gas composition and measurement (for example, the GOST 31371.* series on gas composition determination and uncertainty), GOST 30319.1 (methods for calculating physical properties of natural gas and its components) and international references such as ISO 6976 (methods for calculating calorific values and Wobbe index) which served as a normative basis or reference for some parts of GOST 31369‑2008. The document has later been replaced in national catalogs by GOST 31369‑2021 (revised edition).

Keywords

natural gas; calorific value; heat of combustion; density; relative density; specific gravity; Wobbe index; gas composition; uncertainty; gas analysis; VNIIM; Rosstandart.

FAQ

Q: What is this standard?

A: GOST 31369‑2008 is a technical standard that defines methods to calculate the calorific values (higher and lower), density, relative density and the Wobbe index of natural gas and similar gaseous fuels from their component composition.

Q: What does it cover?

A: It covers mathematical algorithms, recommended reference data for pure components, formats for using molar or mass fractions (and limits for volumetric fractions), procedures for uncertainty estimation, and several informative/normative appendices including computer implementation notes and conversion coefficients.

Q: Who typically uses it?

A: Gas producers, transmission/distribution operators, custody transfer and metering specialists, gas analysis laboratories, standards bodies and software vendors implementing gas property calculators.

Q: Is it current or superseded?

A: The 2008 edition (GOST 31369‑2008) has been catalogued as introduced in 2010 and later catalog entries show it replaced by a revised edition designated GOST 31369‑2021; in practice users should check the national catalog or the latest GOST publication to confirm current applicability in their jurisdiction.

Q: Is it part of a series?

A: Yes — it is functionally linked to other GOST documents covering gas composition determination (GOST 31371 series), methods for calculating gas physical properties (GOST 30319 series) and related metrology/measurement standards; it also aligns conceptually with international standards such as ISO 6976.

Q: What are the key keywords?

A: Calorific value, heat of combustion, density, relative density, Wobbe index, natural gas composition, uncertainty, gas analysis, molar heat, custody transfer.