ISO/TC 30 - Measurement of fluid flow in closed conduits

This document provides guidance on estimating the flowrate when using pressure differential devices constructed or operated outside the scope of ISO 5167 series. Additional tolerances or corrections cannot necessarily compensate for the effects of deviating from ISO 5167 series. The information is given, in the first place, to indicate the degree of care necessary in the manufacture, installation and maintenance of pressure differential devices by describing some of the effects of non-conformity to the requirements; and in the second place, to permit those users who cannot comply fully with the requirements to assess, however roughly, the magnitude and direction of the resulting error in flowrate. Each variation dealt with is treated as though it were the only one present. Where more than one is known to exist, there might be unpredictable interactions and care has to be taken when combining the assessment of these errors. If there is a significant number of errors, means of eliminating some of them have to be considered. The variations included in this document are by no means complete and relate largely to examples with orifice plates. An example with Venturi tubes has been placed at the end of its section. This document does not apply to cone meters or wedge meters. There are, no doubt, many similar examples of installations not conforming to ISO 5167 series for which no comparable data have been published. Such additional information from users, manufacturers and any others can be taken into account in future revisions of this document.

The objective of this document is to provide guidance on the use of ISO 5167:2022 series. ISO 5167:2022 is an International Standard for flow measurement based on the differential pressure generated by a constriction introduced into a circular conduit (see ISO 5167-1:2022, 5.1). It presents a set of rules and requirements based on theory and experimental work undertaken in the field of flow measurement. For a more detailed description of the scope, reference is made to ISO 5167-1:2022, Clause 1. Definitions and symbols applicable to this document are given in ISO 5167-1:2022, Clauses 3 and 4. Neither ISO 5167-1:2022 nor this document gives detailed theoretical background, for which reference is made to any general textbook on fluid flow.

This document defines the measurement of single phase fluid flow rate in closed conduits using radioactive tracer methods.

This document describes the geometry and method of use for conical-entrance orifice plates, quarter-circle orifice plates, eccentric orifice plates and Venturi tubes with 10,5° convergent angles. Information is also given for square-edged orifice plates and nozzles under conditions outside the scope of ISO 5167 series. NOTE The data on which this document is based are limited in some cases.

This document specifies the geometry and method of use (installation and operating conditions) of nozzles and Venturi nozzles when they are inserted in a conduit running full to determine the flowrate of the fluid flowing in the conduit. This document also provides background information for calculating the flowrate and is applicable in conjunction with the requirements given in ISO 5167‑1. This document is applicable to nozzles and Venturi nozzles in which the flow remains subsonic throughout the measuring section and where the fluid can be considered as single-phase. In addition, each of the devices can only be used within specified limits of pipe size and Reynolds number. It is not applicable to the measurement of pulsating flow. It does not cover the use of nozzles and Venturi nozzles in pipe sizes less than 50 mm or more than 630 mm, or where the pipe Reynolds numbers are below 10 000. This document deals with a) three types of standard nozzles: 1) ISA 1932[1] nozzle; 2) the long radius nozzle[2]; 3) the throat-tapped nozzle b) the Venturi nozzle. The three types of standard nozzle are fundamentally different and are described separately in this document. The Venturi nozzle has the same upstream face as the ISA 1932 nozzle, but has a divergent section and, therefore, a different location for the downstream pressure tappings, and is described separately. This design has a lower pressure loss than a similar nozzle. For all of these nozzles and for the Venturi nozzle direct calibration experiments have been made, sufficient in number, spread and quality to enable coherent systems of application to be based on their results and coefficients to be given with certain predictable limits of uncertainty. [1] ISA is the abbreviation for the International Federation of the National Standardizing Associations, which was superseded by ISO in 1946. [2] The long radius nozzle differs from the ISA 1932 nozzle in shape and in the position of the pressure tappings.

This document specifies the geometry and method of use (installation and operating conditions) of cone meters when they are inserted in a conduit running full to determine the flow rate of the fluid flowing in the conduit. As the uncertainty of an uncalibrated cone meter might be too high for a particular application, it might be deemed essential to calibrate the flow meter in accordance with Clause 7. This document also provides background information for calculating the flow rate and is applicable in conjunction with the requirements given in ISO 5167‑1. This document is applicable only to cone meters in which the flow remains subsonic throughout the measuring section and where the fluid can be considered as single-phase. Uncalibrated cone meters can only be used within specified limits of pipe size, roughness, β, and Reynolds number, Re. This document is not applicable to the measurement of pulsating flow. It does not cover the use of uncalibrated cone meters in pipes sized less than 50 mm or more than 500 mm, or where the pipe Reynolds numbers are below 8 × 104 or greater than 1,2 × 107. A cone meter is a primary device which consists of a cone-shaped restriction held concentrically in the centre of the pipe with the nose of the cone upstream. The design of cone meter defined in this document has one or more upstream pressure tappings in the wall, and a downstream pressure tapping positioned in the back face of the cone with the connection to a differential pressure transmitter being a hole through the cone to the support bar, and then up through the support bar. Alternative designs of cone meters are available; however, at the time of writing, there is insufficient data to fully characterize these devices, and therefore, these meters shall be calibrated in accordance with Clause 7.

This document specifies the geometry and method of use (installation and operating conditions) of wedge meters when they are inserted in a conduit running full to determine the flow rate of the fluid flowing in the conduit. NOTE 1 As the uncertainty of an uncalibrated wedge meter can be too large for a particular application, it could be deemed essential to calibrate the flow meter according to Clause 7. This document gives requirements for calibration which, if applied, are for use over the calibrated Reynolds number range. Clause 7 could also be useful guidance for calibration of meters of similar design but which fall outside the scope of this document. It also provides background information for calculating the flow rate and is applicable in conjunction with the requirements given in ISO 5167‑1. This document is applicable only to wedge meters in which the flow remains subsonic throughout the measuring section and where the fluid can be considered as single-phase. Uncalibrated wedge meters can only be used within specified limits of pipe size, roughness, β (or wedge ratio) and Reynolds number. It is not applicable to the measurement of pulsating flow. It does not cover the use of uncalibrated wedge meters in pipes whose internal diameter is less than 50 mm or more than 600 mm, or where the pipe Reynolds numbers are below 1 × 104. NOTE 2 A wedge meter has a primary element which consists of a wedge-shaped restriction of a specific geometry. Alternative designs of wedge meters are available; however, at the time of writing there is insufficient data to fully characterize these devices, and therefore these meters are calibrated in accordance with Clause 7.

This document defines terms and symbols and establishes the general principles for methods of measurement and computation of the flow rate of fluid flowing in a conduit by means of pressure differential devices (orifice plates, nozzles, Venturi tubes, cone meters, and wedge meters) when they are inserted into a circular cross-section conduit running full. This document also specifies the general requirements for methods of measurement, installation and determination of the uncertainty of the measurement of flow rate. ISO 5167 (all parts) is applicable only to flow that remains subsonic throughout the measuring section and where the fluid can be considered as single-phase. It is not applicable to the measurement of pulsating flow.

This document specifies the geometry and method of use (installation in a system and operating conditions) of critical flow nozzles (CFNs) used to determine the mass flow rate of a gas flowing through a system basically without the need to calibrate the CFN. It also gives the information necessary for calculating the flow rate and its associated uncertainty. This document is applicable to nozzles in which the gas flow accelerates to the critical velocity at the minimum flowing section, and only where there is steady flow of single-phase gas. When the critical velocity is attained in the nozzle, the mass flow rate of the gas flowing through the nozzle is the maximum possible for the existing inlet condition, while the CFN can only be used within specified limits, e.g. the CFN throat to inlet diameter ratio and Reynolds number. This document deals with the toroidal- and cylindrical-throat CFNs for which direct calibration experiments have been made in sufficient number to enable the resulting coefficients to be used with certain predictable limits of uncertainty.

This document specifies the geometry and method of use (installation and operating conditions) of Venturi tubes[1] when they are inserted in a conduit running full to determine the flow rate of the fluid flowing in the conduit. This document also provides background information for calculating the flow rate and is applicable in conjunction with the requirements given in ISO 5167-1. This document is applicable only to Venturi tubes in which the flow remains subsonic throughout the measuring section and where the fluid can be considered as single-phase. In addition, Venturi tubes can only be used uncalibrated in accordance with this standard within specified limits of pipe size, roughness, diameter ratio and Reynolds number, or alternatively they can be used across their calibrated range. This document is not applicable to the measurement of pulsating flow. It does not cover the use of uncalibrated Venturi tubes in pipes sized less than 50 mm or more than 1 200 mm, or where the pipe Reynolds numbers are below 2 × 105. This document deals with the three types of classical Venturi tubes: a) “as cast”; b) machined; c) fabricated (also known as “rough-welded sheet-iron”). A Venturi tube consists of a convergent inlet connected to a cylindrical throat which is in turn connected to a conical expanding section called the divergent section (or alternatively the diffuser). Venturi nozzles (and other nozzles) are dealt with in ISO 5167-3. NOTE In the USA the classical Venturi tube is sometimes called the Herschel Venturi tube. [1] In the USA the classical Venturi tube is sometimes called the Herschel Venturi tube.

This document specifies the geometry and method of use (installation and operating conditions) of orifice plates when they are inserted in a conduit running full to determine the flow rate of the fluid flowing in the conduit. This document also provides background information for calculating the flow rate and is applicable in conjunction with the requirements given in ISO 5167‑1. This document is applicable to primary devices having an orifice plate used with flange pressure tappings, or with corner pressure tappings, or with D and D/2 pressure tappings. Other pressure tappings such as “vena contracta” and pipe tappings are not covered by this document. This document is applicable only to a flow which remains subsonic throughout the measuring section and where the fluid can be considered as single phase. It is not applicable to the measurement of pulsating flow[1]. It does not cover the use of orifice plates in pipe sizes less than 50 mm or more than 1 000 mm, or where the pipe Reynolds numbers are below 5 000.

This document specifies a method for the determination in a closed conduit of the volume rate of flow of a regular flow a) of a fluid of substantially constant density or corresponding to a Mach number not exceeding 0,25, b) with substantially uniform stagnation temperature across the measuring cross-section, c) running full in the conduit, and d) under steady flow conditions. In particular, it deals with the technology and maintenance of Pitot static tubes, with the calculation of local velocities from measured differential pressures and with the computation of the flow rate by velocity integration.

This document specifies requirements and recommendations for ultrasonic gas flowmeters (USMs), which utilize the transit time of acoustic signals to measure the flow of single phase homogenous gases in closed conduits. This document applies to transit time ultrasonic gas flowmeters used for custody transfer and allocation metering, such as full-bore, reduced-area, high-pressure, and low-pressure meters or any combination of these. There are no limits on the minimum or maximum sizes of the meter. This document can be applied to the measurement of almost any type of gas, such as air, natural gas, and ethane. Included are flow measurement performance requirements for meters of two accuracy classes suitable for applications such as custody transfer and allocation measurement. This document specifies construction, performance, calibration, diagnostics for meter verification, and output characteristics of ultrasonic meters for gas flow measurement and deals with installation conditions. NOTE It is possible that national or other regulations apply which can be more stringent than those in this document.

This document gives guidelines for the specification, testing, inspection, installation, operation and calibration of thermal mass gas flowmeters for the metering of gases and gas mixtures. It is not applicable to measuring liquid mass flowrates using thermal mass flowmeters. This document is not applicable to hot wire and other hot film anemometers, also used in making point velocity measurements.

ISO/TR 3313:2018 defines pulsating flow, compares it with steady flow, indicates how it can be detected, and describes the effects it has on orifice plates, nozzles or Venturi tubes, turbine and vortex flowmeters when these devices are being used to measure fluid flow in a pipe. These particular flowmeter types feature in this document because they are amongst those types most susceptible to pulsation effects. Methods for correcting the flowmeter output signal for errors produced by these effects are described for those flowmeter types for which this is possible. When correction is not possible, measures to avoid or reduce the problem are indicated. Such measures include the installation of pulsation damping devices and/or choice of a flowmeter type which is less susceptible to pulsation effects. ISO/TR 3313:2018 applies to flow in which the pulsations are generated at a single source which is situated either upstream or downstream of the primary element of the flowmeter. Its applicability is restricted to conditions where the flow direction does not reverse in the measuring section but there is no restriction on the waveform of the flow pulsation. The recommendations within this document apply to both liquid and gas flows although with the latter the validity might be restricted to gas flows in which the density changes in the measuring section are small as indicated for the particular type of flowmeter under discussion.

ISO/TR 15377:2018 describes the geometry and method of use for conical-entrance orifice plates, quarter-circle orifice plates, eccentric orifice plates and Venturi tubes with 10,5° convergent angles. Recommendations are also given for square-edged orifice plates and nozzles under conditions outside the scope of ISO 5167. NOTE The data on which this document is based are limited in some cases.

ISO 20456:2017 applies to industrial electromagnetic flowmeters used for the measurement of flowrate of a conductive liquid in a closed conduit running full. It covers flowmeter types utilizing both alternating current (AC) and pulsed direct current (DC) circuits to drive the field coils and meters running from a mains power supply and those operating from batteries or other sources of power. ISO 20456:2017 is not applicable to insertion-type flowmeters or electromagnetic flowmeters designed to work in open channels or pipes running partially full, nor does it apply to the measurement of magnetically permeable slurries or liquid metal applications. ISO 20456:2017 does not specify safety requirements in relation to hazardous environmental usage of the flowmeter.

ISO 12764:2017 a) describes the use of vortex shedding flow meters for liquids, gases, and steam, including a glossary and a set of engineering equations used for specifying performance, b) provides technical information to assist the user in selecting, specifying and applying vortex shedding flowmeters, including influence effects, c) describes typical construction and provides recommendations for inspection, certification, and material traceability, d) describes availability of diagnostics associated with vortex shedding flowmeters, e) provides calibration guidance, f) does not apply to insertion type vortex shedding flowmeters, g) applies only to closed conduits running full, h) applies only to fluid flow that is steady or varies only slowly with time, and i) applies to fluids considered to be single-phase.

ISO 10790:2015 gives guidelines for the selection, installation, calibration, performance, and operation of Coriolis flowmeters for the measurement of mass flow and density. This International Standard also gives appropriate considerations regarding the type of fluids measured, as well as guidance in the determination of volume flow and other related fluid parameters. NOTE Fluids defined as air, natural gas, water, oil, LPG, LNG, manufactured gases, mixtures, slurries, etc.

ISO 4064-3:2014|OIML R 49-3:2013 specifies a test report format to be used in conjunction with ISO 4064-1:2014|OIML R 49-1:2013 and ISO 4064-2:2014|OIML R 49-2:2013 for water meters for cold potable water and hot water.

ISO 4064-1:2014|OIML R 49-1:2013 specifies metrological and technical requirements of water meters for cold potable water and hot water flowing through a fully charged, closed conduit. These water meters incorporate devices which indicate the integrated volume. In addition to water meters based on mechanical principles, ISO 4064-1:2014|OIML R 49-1:2013 applies to devices based on electrical or electronic principles, and mechanical principles incorporating electronic devices, used to measure the volume of cold potable water and hot water. ISO 4064-1:2014|OIML R 49-1:2013 also applies to electronic ancillary devices. Ancillary devices are optional. However, it is possible for national or regional regulations to make some ancillary devices mandatory in relation to the utilization of water meters.

ISO 4064-5:2014 applies to water meters used to meter the volume of cold potable water and hot water flowing through a fully charged, closed conduit. These water meters incorporate devices which indicate the integrated volume. ISO 4064-5:2014 specifies criteria for the selection of single, combination and concentric water meters, associated fittings, installation, special requirements for meters, and the first operation of new or repaired meters to ensure accurate constant measurement and reliable reading of the meter. In addition to meters based on mechanical principles, ISO 4064-5:2014 also applies to water meters based on electrical or electronic principles, and to water meters based on mechanical principles incorporating electronic devices, used to measure the volume of cold potable water and hot water. It also applies to electronic ancillary devices. Ancillary devices are optional. However, national or international regulations may make some ancillary devices mandatory in relation to the utilization of the water meter. The recommendations of ISO 4064-5:2014 apply to water meters, irrespective of technology, defined as integrating measuring instruments continuously determining the volume of water flowing through them.

ISO 4064-4:2014 applies to water meters used to meter the volume of cold potable water and hot water flowing through a fully charged, closed conduit. These water meters incorporate devices which indicate the integrated volume. ISO 4064-4:2014 specifies technical characteristics and pressure loss requirements for meters for cold potable water and hot water. It applies to water meters which can withstand: a) a maximum admissible working pressure (MAP) equal to at least 1 MPa [0,6 MPa for meters for use with pipe nominal diameters (DNs) ≥500 mm]; b) a maximum admissible temperature (MAT) for cold potable water meters of 30 °C; c) a MAT for hot water meters up to 180 °C, depending on class. In addition to meters based on mechanical principles, ISO 4064-4:2014 also applies to water meters based on electrical or electronic principles, and to water meters based on mechanical principles incorporating electronic devices, used to meter the volume flow of hot water and cold potable water. It also applies to electronic ancillary devices. As a rule ancillary devices are optional. However, national or international regulations may make some ancillary devices mandatory in relation to the utilization of the water meter.

ISO 4064-2:2014|OIML R 49-2:2013 is applicable to the type evaluation and initial verification testing of water meters for cold potable water and hot water as defined in ISO 4064‑1:2014|OIML R 49‑1:2013. OIML Certificates of Conformity can be issued for water meters under the scope of the OIML Certificate System, provided that ISO 4064-2:2014|OIML R 49-2:2013, ISO 4064‑1:2014|OIML R 49‑1:2013 and ISO 4064‑3:2014|OIML R 49‑3:2013 are used in accordance with the rules of the system. ISO 4064-2:2014|OIML R 49-2:2013 sets out details of the test programme, principles, equipment and procedures to be used for the type evaluation, and initial verification of a meter type. The provisions of ISO 4064-2:2014|OIML R 49-2:2013 also apply to ancillary devices, if required by national regulations. The provisions include requirements for testing the complete water meter and for testing the measurement transducer (including the flow or volume sensor) and the calculator (including the indicating device) of a water meter as separate units.

This part of ISO 17089 specifies requirements and recommendations for ultrasonic gas meters (USMs), which utilize acoustic signals to measure the flow in the gaseous phase in closed conduits. This part of ISO 17089 is applicable to transit time USMs and is focused towards industrial flow measurement. Included are meters comprising meter bodies as well as meters with field-mounted transducers. There are no limits on the size of the meter. It can be applied to the measurement of almost any type of gas; such as but not limited to air, hydrocarbon gases, and steam. This part of ISO 17089 specifies performance, calibration (when required), and output characteristics of USMs for gas flow measurement and deals with installation conditions. NOTE It is possible that national or other regulations apply which can be more stringent than those in this part of ISO 17089.

ISO 12242:2012 specifies requirements and recommendations for ultrasonic liquid flowmeters, which utilize the transit time of ultrasonic signals to measure the flow of single-phase homogenous liquids in closed conduits. There are no limits on the minimum or maximum sizes of the meter. ISO 12242:2012 specifies performance, calibration and output characteristics of ultrasonic meters (USMs) for liquid flow measurement and deals with installation conditions. It covers installation with and without a dedicated proving (calibration) system. It covers both in-line and clamp-on transducers (used in configurations in which the beam is non-refracted and in those in which it is refracted). Included are both meters incorporating meter bodies and meters with field-mounted transducers.

ISO/TR 11583:2012 describes the measurement of wet gas with differential pressure meters. It applies to two-phase flows of gas and liquid in which the flowing fluid mixture consist of gas in the region of 95 % volume fraction or more. ISO/TR 11583:2012 is an extension of ISO 5167. The ranges of gases and liquids from which the equations in ISO/TR 11583:2012 were derived are given. It is possible that the equations do not apply to liquids significantly different from those tested, particularly to highly viscous liquids. Although the over-reading equations presented in ISO/TR 11583:2012 apply for a wide range of gases and liquids at appropriate gas-liquid density ratios, evaluating gas flow rates depends on information in addition to that required in single-phase flow: a measurement of the pressure loss can be sufficient; measurement of the liquid flow using tracers can be possible; the total mass flow rate may be known (this is more likely in a wet-steam flow than in a natural gas/liquid flow); in a wet-steam flow a throttling calorimeter can be used. Wet-gas measurement using Venturi tubes or orifice plates is covered in ISO/TR 11583:2012.

ISO 22158:2011 specifies the minimum communication requirements for water meters which have the capability to exchange or provide data by means of an electronic interface. ISO 22158:2011 only specifies the interface conditions present at the electrical and electronic connections of water meters and does not prescribe any specific equipment such as transponders and inductive pads, which might be connected to the water meter for automatic meter reading or remote meter reading purposes.

ISO 7194:2008 specifies velocity-area methods for measuring flow in swirling or asymmetric flow conditions in circular ducts by means of current-meters of Pitot static tubes. ISO 7194:2008 specifies the measurements required, the precautions to be taken, the corrections to apply, and describes the additional uncertainties which are introduced when a measurement in asymmetric or swirling flow has to be made. Only flows with a negligible radial component are considered, however. Furthermore, it is not possible to make a measurement in accordance with ISO 7194:2008 if, at any point in the measuring cross-section, the local velocity makes an angle of greater than 40° with the axis of the duct, or where the index of asymmetry Y (defined within ISO 7194:2008) is greater than 0,15. ISO 7194:2008 deals only with instruments for measuring local velocity as defined in ISO 3354 and ISO 3966. If Pitot static tubes are used, ISO 7194:2008 applies only to flows where the Mach number corresponding to local velocities does not exceed 0,25.

ISO 3354:2008 specifies a method for the determination of the volume flow-rate in a closed conduit by means of the velocity-area method using propeller-type current-meters under the following conditions: a) the velocity distribution is regular; b) the fluid is water which is clean or considered to be clean; c) the conduit is full; d) the flow is steady. ISO 3354:2008 deals in particular with the technology and calibration of propeller-type current-meters, the measurement of local velocities and the calculation of the flow-rate by velocity integration.

ISO 2186:2007 sets out provisions for the design, lay-out and installation of a pressure signal transmission system, whereby a pressure signal from a primary fluid flow device can be transmitted by known techniques to a secondary device safely and in such a way that the value of the signal is not distorted or modified.

ISO 5168:2005 establishes general principles and describes procedures for evaluating the uncertainty of a fluid flow-rate or quantity. A step-by-step procedure for calculating uncertainty is given.

Specifies dimensions, ranges, construction, performance, calibration and output characteristics of the turbine meters. Also deals with installation conditions, leakage testing und pressure testing and provides a series of informative annexes A to E including recommendations for use, field checks, and perturbations of the fluid flowing. In many countries, some or all of the items covered are subject to mandatory regulations imposed by the laws of these countries. Where conflicts exist, the mandatory regulations shall prevail.

Corrects subclause 1.5 (Notation) and equation (1) of annex C.

Specifies methods of testing installations for flowrate measurement by the static weighing method. Table 1 lists the symbols of concern. The normative annexes A to E contain various examples for error estimation, assessment of the uncertainty and flowrate stability.

Describes the procedures for fitting a quadratic, cubic or higher degree polynomial expression to a non-linear set of calibration data, using the least-squares criterion, and of assessing the uncertainty associated with the resulting calibration curve. The method of fitting a straight line to flow measurement calibration data is dealt with in ISO 7066-1.

The specified measuring methods are built upon the determination of the volume of liquid collected in a volumetric tank in a known time interval. Deals in particular with the measuring apparatus, the procedure, the method for calculating the flow-rate and the assessment of uncertainties associated with the measurements.

Specifies a method of determining the liquid flow-rate by measuring the mass of liquid delivered into a weighing tank in a known time intervall. Deals in particular with the measuring apparatus, the procedure, the method for calculating the flow-rate and the uncertainties associated with the measurement. Does not cover the cases of corrosive or toxic liquids.

Tracer methods apply to flow measurement in conduits into which a solution can be injected and those cases where effective mixing of this solution with the water flowing in the conduit can be achieved, this last condition being fundamental. Describes the transit time method using radioactive tracers for the measurement of water flow rate in closed conduits.

Tracer methods apply to flow measurement in conduits into which a solution can be injected and those cases where effective mixing of this solution with the water flowing in the conduit can be achieved, this last condition being fundamental. Describes the transit time method using non-radioactive tracers for the measurement of water flow rate in closed conduits.

Tracer methods apply to flow measurement in conduits into which a solution can be injected and those cases where effective mixing of this solution with the water flowing in the conduit can be achieved, this last condition being fundamental. Describes the method of constant injection rate using radioactive tracers.

Tracer methods apply to flow measurement in conduits into which a solution can be injected and those cases where effective mixing of this solution with the water flowing in the conduit can be achieved, this last condition being fundamental. Describes the method of constant injection rate using non-radioactive tracers.

Tracer methods apply to flow measurement in conduits into which a solution can be injected and those cases where effective mixing of this solution with the water flowing in the conduit can be achieved, this last condition being fundamental. Covers choice of method, choice of tracer, choice of measuring length and adequate mixing distance, and possible errors.

This document specifies requirements and recommendations for non-intrusive (clamp-on) ultrasonic flowmeters (USMs), which utilize the transit time of ultrasonic signals to measure the flow of predominantly single-phase homogenous fluids (liquids and gases) in closed conduits. This document specifies performance, calibration, and output characteristics, and deals with installation conditions.

This document specifies the geometry and method of use (installation and operating conditions) of nozzles and Venturi nozzles when they are inserted in a conduit running full to determine the flowrate of the fluid flowing in the conduit. This document also provides background information for calculating the flowrate and is applicable in conjunction with the requirements given in ISO 5167‑1. This document is applicable to nozzles and Venturi nozzles in which the flow remains subsonic throughout the measuring section and where the fluid can be considered as single-phase. In addition, each of the devices can only be used within specified limits of pipe size and Reynolds number. It is not applicable to the measurement of pulsating flow. It does not cover the use of nozzles and Venturi nozzles in pipe sizes less than 50 mm or more than 630 mm, or where the pipe Reynolds numbers are below 10 000. This document deals with a) three types of standard nozzles: ISA 1932[1] nozzle; the long radius nozzle[2]; the throat-tapped nozzle b) the Venturi nozzle. The three types of standard nozzle are fundamentally different and are described separately in this document. The Venturi nozzle has the same upstream face as the ISA 1932 nozzle, but has a divergent section and, therefore, a different location for the downstream pressure tappings, and is described separately. This design has a lower pressure loss than a similar nozzle. For all of these nozzles and for the Venturi nozzle direct calibration experiments have been made, sufficient in number, spread and quality to enable coherent systems of application to be based on their results and coefficients to be given with certain predictable limits of uncertainty. [1] ISA is the abbreviation for the International Federation of the National Standardizing Associations, which was superseded by ISO in 1946. [2] The long radius nozzle differs from the ISA 1932 nozzle in shape and in the position of the pressure tappings.

This document specifies the geometry and method of use (installation and operating conditions) of wedge meters when they are inserted in a conduit running full to determine the flow rate of the fluid flowing in the conduit. NOTE 1 As the uncertainty of an uncalibrated wedge meter can be too large for a particular application, it could be deemed essential to calibrate the flow meter according to Clause 7. This document gives requirements for calibration which, if applied, are for use over the calibrated Reynolds number range. Clause 7 could also be useful guidance for calibration of meters of similar design but which fall outside the scope of this document. It also provides background information for calculating the flow rate and is applicable in conjunction with the requirements given in ISO 5167‑1. This document is applicable only to wedge meters in which the flow remains subsonic throughout the measuring section and where the fluid can be considered as single-phase. Uncalibrated wedge meters can only be used within specified limits of pipe size, roughness, beta (or wedge ratio) and Reynolds number. It is not applicable to the measurement of pulsating flow. It does not cover the use of uncalibrated wedge meters in pipes whose internal diameter is less than 50 mm or more than 600 mm, or where the pipe Reynolds numbers are below 1 × 104. NOTE 2 A wedge meter has a primary element which consists of a wedge-shaped restriction of a specific geometry. Alternative designs of wedge meters are available; however, at the time of writing there is insufficient data to fully characterize these devices, and therefore these meters are calibrated in accordance with Clause 7.

ISO 5167-5:2016 specifies the geometry and method of use (installation and operating conditions) of cone meters when they are inserted in a conduit running full to determine the flow rate of the fluid flowing in the conduit. As the uncertainty of an uncalibrated cone meter might be too high for a particular application, it might be deemed essential to calibrate the flow meter in accordance with Clause 7. ISO 5167-5:2016 also provides background information for calculating the flow rate and is applicable in conjunction with the requirements given in ISO 5167‑1. ISO 5167-5:2016 is applicable only to cone meters in which the flow remains subsonic throughout the measuring section and where the fluid can be considered as single-phase. Uncalibrated cone meters can only be used within specified limits of pipe size, roughness, β, and Reynolds number. This part of ISO 5167 is not applicable to the measurement of pulsating flow. It does not cover the use of uncalibrated cone meters in pipes sized less than 50 mm or more than 500 mm, or where the pipe Reynolds numbers are below 8 × 104 or greater than 1,2 × 107. A cone meter is a primary device which consists of a cone-shaped restriction held concentrically in the centre of the pipe with the nose of the cone upstream. The design of cone meter defined in this part of ISO 5167 has one or more upstream pressure tappings in the wall, and a downstream pressure tapping positioned in the back face of the cone with the connection to a differential pressure transmitter being a hole through the cone to the support bar, and then up through the support bar. Alternative designs of cone meters are available; however, at the time of writing, there is insufficient data to fully characterize these devices, and therefore, these meters shall be calibrated in accordance with Clause 7.

ISO 17089-1:2010 specifies requirements and recommendations for ultrasonic gas flowmeters (USMs), which utilize the transit time of acoustic signals to measure the flow of single phase homogenous gases in closed conduits. ISO 17089-1:2010 applies to transit time ultrasonic gas flowmeters used for custody transfer and allocation metering, such as full-bore, reduced-area, high-pressure, and low-pressure meters or any combination of these. There are no limits on the minimum or maximum sizes of the meter. ISO 17089-1:2010 can be applied to the measurement of almost any type of gas, such as air, natural gas, and ethane. Included are flow measurement performance requirements for meters of two accuracy classes suitable for applications such as custody transfer and allocation measurement. ISO 17089-1:2010 specifies construction, performance, calibration, and output characteristics of ultrasonic meters for gas flow measurement and deals with installation conditions.