GB/T 21446-2008
Measurement of natural gas flow by means of standard orifice meter (English Version)

Standard No.

GB/T 21446-2008

Language

Chinese, Available in English version

Release Date

2008

Published By

General Administration of Quality Supervision, Inspection and Quarantine of the People‘s Republic of China

Latest

GB/T 21446-2008

Scope

This standard specifies the structural form and technical requirements of the standard orifice plate; the pressure taking method, use method, installation and operation conditions, and inspection requirements of the throttling device; the volume flow, energy flow, mass flow and measurement of natural gas under standard reference conditions. Calculation method of uncertainty. At the same time, the necessary information for calculating the flow rate and its related uncertainties are also given. This standard is applicable to throttling devices whose pressure taking methods are flange pressure taking and angle connection pressure taking. Standard orifice plates are used to measure the flow rate of mixed gas with methane as the main component produced in gas fields or oil fields. This standard does not apply to the occasions where the opening diameter of the orifice plate is less than 12.5mm, the inner diameter of the measuring tube is less than 50mm and greater than 1000mm, the diameter ratio is less than 0.1 and greater than 0.75, and the pipe diameter Reynolds number is less than 5000. Reconstructed or newly constructed metering systems shall meet the requirements of this standard. This standard does not emphasize updating established metering systems. If the metering system does not meet the requirements of this standard, there may be additional errors in the metering system due to the incompatibility between the flow conditions and the upstream straight pipe section.

GB/T 21446-2008 Referenced Document

• GB 3836.1 Explosive atmospheres.Part 1:Equipment.General requirements*， 2010-08-09 Update
• GB/T 11062-1998 Natural gas--Calculation of calorific values, density, relative density and Wobbe index from composition
• GB/T 15464-1995 Gmeneral-purpose specification for the packaging instrumentation products
• GB/T 17747.1 Natural gas.Caculation of compression factor.Part 1: Introduction and guidelines*， 2011-12-05 Update
• GB/T 17747.2 Natural gas.Calculation of compression factor.Part 2: Calculation using molar-composition analysis *， 2011-12-30 Update
• GB/T 17747.3 Natural gas.Caculation of compression factor.Part 3: Caculation using physical properties*， 2011-12-05 Update
• GB/T 18603-2001 Technical requirements of measuring systems for natural gas
• GB/T 8170-1987 Rules for rounding off of numerical values
• JJF 1059-1999 Evaluation and Expression of Uncertainty in Measurement
• JJG 640-1994 Verification Regulation of Differential Pressure Type Flowmeter

GB/T 21446-2008 history

• 2008 GB/T 21446-2008 Measurement of natural gas flow by means of standard orifice meter