ISO 15970:2008
Natural gas - Measurement of properties - Volumetric properties: density, pressure, temperature and compression factor

Standard No.

ISO 15970:2008

Release Date

2008

Published By

International Organization for Standardization (ISO)

Latest

ISO 15970:2008

Scope

This international Standard gives requirements and procedures for the measurement of the properties of natural gas that are used mainly for volume calculation and volume conversion: density at reference and at operating conditions, pressure, temperature and compression factor. Only those methods and instruments are considered that are suitable for field operation under the conditions of natural gas transmission and distribution, installed either in-line or on-line, and that do not involve the determination of the gas composition. This International Standard gives examples for currently used instruments that are available commercially and of interest to the natural gas industry. NOTE Attention is drawn to requirements for approval of national authorization agencies and to national legal regulations for the use of these devices for commercial or official trade purposes. The density at reference conditions (sometimes referred to as normal, standard or even base density) is required for conversion of volume data and can be used for other physical properties. Density at operating conditions is measured for mass-flow measurement and volume conversion using the observed line density and can be used for other physical properties. This International Standard covers density transducers based on vibrating elements, normally suitable for measuring ranges of 5 kg/m3 to 250 kg/m3. Pressure measurement deals with differential, gauge and absolute pressure transmitters. It considers both analogue and smart transmitters (i.e. microprocessor based instruments) and, if not specified otherwise, the corresponding paragraphs refer to differential, absolute and gauge pressure transmitters without distinction. Temperature measurements in natural gas are performed within the range of conditions under which transmission and distribution are normally carried out (253 K< 7'<338 K). In this field of application, resistance thermometer detectors (RTD) are generally used. The compression factor (also known as the compressibility factor or the real gas factor and given the symbol Z) appears, in particular, in equations governing volumetric metering. Moreover, the conversion of volume at metering conditions to volume at defined reference conditions can properly proceed with an accurate knowledge of Z at both relevant pressure and relevant temperature conditions.

ISO 15970:2008 Referenced Document

• IEC 60079-0 Interpretation Sheet 2 - Explosive atmospheres - Part 0: Equipment - General requirements*， 2019-06-27 Update
• IEC 60079-1 Interpretation sheet 1 - Explosive atmospheres - Part 1: Equipment protection by flameproof enclosures "d"*， 2020-05-28 Update
• IEC 60381-1 Analogue signals for process control systems. Part 1 : Direct current signals
• IEC 60381-2 Analogue signals for process control systems. Part 2 : Direct voltage signals
• IEC 60751 Industrial platinum resistance thermometers and platinum temperature sensors*， 2022-01-27 Update
• IEC 60770-1 Transmitters for use in industrial-process control systems - Part 1: Methods for performance evaluation*， 2010-07-01 Update
• ISO 10715 Natural gas — Gas sampling*， 2022-10-04 Update
• ISO 12213-1 Natural gas - Calculation of compression factor - Part 1: Introduction and guidelines
• ISO 2186 Fluid flow in closed conduits - Connections for pressure signal transmissions between primary and secondary elements
• ISO 5167-1 Measurement of fluid flow by means of pressure differential devices inserted in circular cross-section conduits running full — Part 1: General principles and requirements*， 2022-06-16 Update
• ISO 6976 Natural gas - Calculation of calorific values, density, relative density and Wobbe indices from composition*， 2016-08-01 Update

ISO 15970:2008 history

• 2008 ISO 15970:2008 Natural gas - Measurement of properties - Volumetric properties: density, pressure, temperature and compression factor