Measurement of fluid flow in closed conduits — Guidance to the selection, installation and use of Coriolis flowmeters (mass flow, density and volume flow measurements)

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.

Mesure de débit des fluides dans les conduites fermées — Lignes directrices pour la sélection, l'installation et l'utilisation des mesureurs à effet Coriolis (mesurages de débit-masse, masse volumique et débit-volume)

General Information

Status
Published
Publication Date
01-Apr-2015
Current Stage
9093 - International Standard confirmed
Start Date
23-Nov-2020
Completion Date
23-Nov-2020
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INTERNATIONAL ISO
STANDARD 10790
Third edition
2015-04-01
Measurement of fluid flow in closed
conduits — Guidance to the selection,
installation and use of Coriolis
flowmeters (mass flow, density and
volume flow measurements)
Mesure de débit des fluides dans les conduites fermées — Lignes
directrices pour la sélection, l’installation et l’utilisation des
mesureurs à effet Coriolis (mesurages de débit-masse, masse
volumique et débit-volume)
Reference number
ISO 10790:2015(E)
ISO 2015
---------------------- Page: 1 ----------------------
ISO 10790:2015(E)
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© ISO 2015

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ii © ISO 2015 – All rights reserved
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ISO 10790:2015(E)
Contents Page

Foreword ..........................................................................................................................................................................................................................................v

Introduction ................................................................................................................................................................................................................................vi

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 1

3.1 Definitions specific to this Coriolis flowmeter standard .................................................................................... 1

3.2 Definitions from VIM, ISO/IEC Guide 99 (JCGM:2012) ........................................................................................ 3

3.3 Symbols ......................................................................................................................................................................................................... 4

3.4 Abbrevations ............................................................................................................................................................................................. 5

4 Coriolis flowmeter selection criteria .............................................................................................................................................. 5

4.1 General ........................................................................................................................................................................................................... 5

4.2 Physical installation ............................................................................................................................................................................ 5

4.2.1 General...................................................................................................................................................................................... 5

4.2.2 Installation criteria ........................................................................................................................................................ 6

4.2.3 Full-pipe requirement for liquids ...................................................................................................................... 6

4.2.4 Orientation ............................................................................................................................................................................ 6

4.2.5 Flow conditions and straight length requirements ........................................................................... 6

4.2.6 Valves ......................................................................................................................................................................................... 6

4.2.7 Cleaning ................................................................................................................................................................................... 6

4.2.8 Hydraulic and mechanical vibrations ............................................................................................................ 7

4.2.9 Pipe stress and torsion ............................................................................................................................................... 7

4.2.10 Crosstalk between sensors ..................................................................................................................................... 7

4.3 Effects due to process conditions and fluid properties ........................................................................................ 7

4.3.1 General...................................................................................................................................................................................... 7

4.3.2 Application and fluid properties ........................................................................................................................ 7

4.3.3 Multiphase flow ................................................................................................................................................................ 8

4.3.4 Influence of process fluid ......................................................................................................................................... 8

4.3.5 Temperature effects ...................................................................................................................................................... 8

4.3.6 Pressure effects ................................................................................................................................................................. 9

4.3.7 Pulsating flow effects ................................................................................................................................................... 9

4.3.8 Viscosity effects ................................................................................................................................................................ 9

4.3.9 Flashing and/or cavitation ...................................................................................................................................... 9

4.4 Pressure loss ............................................................................................................................................................................................. 9

4.5 Safety ............................................................................................................................................................................................................... 9

4.5.1 General...................................................................................................................................................................................... 9

4.5.2 Hydrostatic pressure test ......................................................................................................................................... 9

4.5.3 Mechanical stress .........................................................................................................................................................10

4.5.4 Erosion...................................................................................................................................................................................10

4.5.5 Corrosion .............................................................................................................................................................................10

4.5.6 Housing design ...............................................................................................................................................................10

4.5.7 Cleaning ................................................................................................................................................................................10

4.6 Transmitter (secondary device) ...........................................................................................................................................10

4.7 Diagnostics ..............................................................................................................................................................................................11

5 Inspection and compliance .....................................................................................................................................................................11

6 Mass flow measurement ............................................................................................................................................................................12

6.1 Apparatus .................................................................................................................................................................................................12

6.1.1 Principle of operation ...............................................................................................................................................12

6.1.2 Coriolis sensor ................................................................................................................................................................14

6.1.3 Coriolis transmitter ....................................................................................................................................................15

6.2 Mass flow measurement ..............................................................................................................................................................15

6.3 Factors affecting mass flow measurement...................................................................................................................17

6.3.1 Density and viscosity ................................................................................................................................................17

© ISO 2015 – All rights reserved iii
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ISO 10790:2015(E)

6.3.2 Multiphase flow .............................................................................................................................................................17

6.3.3 Temperature .....................................................................................................................................................................18

6.3.4 Pressure ................................................................................................................................................................................18

6.3.5 Installation .........................................................................................................................................................................18

6.4 Zero adjustment ..................................................................................................................................................................................18

6.5 Calibration of mass flow measurement ..........................................................................................................................18

7 Density measurement ..................................................................................................................................................................................19

7.1 General ........................................................................................................................................................................................................19

7.2 Principle of operation ....................................................................................................................................................................20

7.3 Specific gravity of fluids ...............................................................................................................................................................21

7.4 Density measurement uncertainty .....................................................................................................................................21

7.5 Factors affecting density measurement .........................................................................................................................21

7.5.1 Temperature .....................................................................................................................................................................21

7.5.2 Pressure ................................................................................................................................................................................22

7.5.3 Multiphase (Two phase).........................................................................................................................................22

7.5.4 Flow effect ..........................................................................................................................................................................22

7.5.5 Corrosion and erosion ........................................................................................................................................... ...22

7.5.6 Coatings ................................................................................................................................................................................22

7.5.7 Installation .........................................................................................................................................................................22

7.6 Density calibration and adjustment ..................................................................................................................................22

7.6.1 General...................................................................................................................................................................................22

7.6.2 Manufacturer’s density calibration ...............................................................................................................22

7.6.3 Field density calibration and adjustment................................................................................................23

8 Volume flow measurement at metering conditions ......................................................................................................23

8.1 General ........................................................................................................................................................................................................23

8.2 Volume calculation ...........................................................................................................................................................................23

8.3 Gas as a process fluid ......................................................................................................................................................................24

8.4 Volume measurement uncertainty .....................................................................................................................................24

8.5 Special influences ..............................................................................................................................................................................24

8.5.1 General...................................................................................................................................................................................24

8.5.2 Empty pipe effect ..........................................................................................................................................................24

8.5.3 Multiphase fluids ..........................................................................................................................................................24

8.6 Factory calibration ............................................................................................................................................................................24

8.6.1 Mass flow and density ..............................................................................................................................................24

8.7 Volume check .........................................................................................................................................................................................25

Annex A (informative) Calibration techniques .......................................................................................................................................26

Annex B (informative) Safety guidelines for the selection of Coriolis flowmeters ............................................29

Annex C (informative) Considerations for multi-component liquid systems .........................................................31

Annex D (informative) Miscible liquids containing chemically non-interacting components ..............34

Bibliography .............................................................................................................................................................................................................................37

iv © ISO 2015 – All rights reserved
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ISO 10790:2015(E)
Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards

bodies (ISO member bodies). The work of preparing International Standards is normally carried out

through ISO technical committees. Each member body interested in a subject for which a technical

committee has been established has the right to be represented on that committee. International

organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.

ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of

electrotechnical standardization.

The procedures used to develop this document and those intended for its further maintenance are

described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the

different types of ISO documents should be noted. This document was drafted in accordance with the

editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of any

patent rights identified during the development of the document will be in the Introduction and/or on

the ISO list of patent declarations received (see www.iso.org/patents).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation on the meaning of ISO specific terms and expressions related to conformity

assessment, as well as information about ISO’s adherence to the WTO principles in the Technical Barriers

to Trade (TBT), see the following URL: Foreword — Supplementary information.

The committee responsible for this document is ISO/TC 30, Measurement of fluid flow in closed conduits,

Subcommittee SC 5, Velocity and mass methods.

This third edition cancels and replaces the second edition (ISO 10790:1999), which has been technically

revised. It also incorporates the Amendment ISO 10790:1999/Amd 1:2003.
© ISO 2015 – All rights reserved v
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ISO 10790:2015(E)
Introduction

This International Standard has been prepared as a guide for those concerned with the selection, testing,

inspection, operation, and calibration of Coriolis flowmeters (Coriolis flowmeter assemblies). A list of

related International Standards is in the Bibliography.
This International Standard provides the following:
a) description of the Coriolis operating principle;
b) guideline to expected performance characteristics of Coriolis flowmeters;
c) description of calibration, verification, and checking procedures;
d) description of potential error sources;
e) common set of terminology, symbols, definitions, and specifications.

The next paragraphs contain an explanation of when to use the measurement terminology, uncertainty,

and accuracy.

The VIM definition (see 3.2) of accuracy: closeness of agreement between a measured quantity value

and a “true quantity value” of a measurand. Per the VIM, accuracy is a quality and should not be given a

numerical value.

To understand the preceding paragraph, one needs to understand that a “true quantity value” does

not exist. The best that can be done is to determine the measured quantity value with measurement

instrumentation calibrated with a very good but imperfect reference. Therefore, the measurement is an

estimate. Uncertainty is used to define these measurement estimates (see 3.2.2).

Many Coriolis manufacturers use accuracy and zero stability as part of their published performance

specifications. The manufacturer’s accuracy specification includes repeatability, hysteresis, and

linearity but can also include other items that might be different for each manufacturer.

This International Standard will use uncertainty to quantify the results of a flow measurement system.

This International Standard will only use accuracy when it is very clear that it is referring to or using all

or part of the manufacturers published specifications.
vi © ISO 2015 – All rights reserved
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INTERNATIONAL STANDARD ISO 10790:2015(E)
Measurement of fluid flow in closed conduits — Guidance
to the selection, installation and use of Coriolis flowmeters
(mass flow, density and volume flow measurements)
1 Scope

This International Standard 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.

2 Normative references

The following documents, in whole or in part, are normatively referenced in this document and are

indispensable for its application. For dated references, only the edition cited applies. For undated

references, the latest edition of the referenced document (including any amendments) applies.

ISO 5168, Measurement of fluid flow — Procedures for the evaluation of uncertainties

ISO/IEC 17025, General requirements for the competence of testing and calibration laboratories

ISO/IEC Guide 99:2007 (JCGM 200:2012), International vocabulary of metrology — Basic and general

concepts and associated terms (VIM)
3 Terms and definitions
3.1 Definitions specific to this Coriolis flowmeter standard
For the purposes of this document, the following terms and definitions apply.
3.1.1
Coriolis flowmeter

device consisting of a flow sensor (primary device) and a transmitter (secondary device) which measures

mass flow and density by means of the interaction between a flowing fluid and the oscillation of a tube

or tubes
Note 1 to entry: This can also provide measurement of the tube(s) temperature.
3.1.2
flow sensor (primary device)

mechanical assembly consisting of an oscillating tube(s), drive system, measurement sensor(s),

supporting structure, and housing
3.1.3
transmitter (secondary device)

electronic control system providing the drive electrical supply and transforming the signals from the

flow sensor to give output(s) of measured and inferred parameters

Note 1 to entry: It also provides corrections derived from parameters such as temperature.

Note 2 to entry: The transmitter (secondary device) is either integrally mounted (compact device) on the flow

sensor (primary device) or remotely installed away from the primary device and connected by a cable.

© ISO 2015 – All rights reserved 1
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ISO 10790:2015(E)
3.1.4
oscillating tube
tube through which the fluid to be measured flows
3.1.5
drive system
means for inducing the oscillation of the tube(s)
3.1.6
sensing device

sensor to detect the effect of the Coriolis force and to measure the frequency of the tube oscillations

3.1.7
supporting structure
support for the oscillating tube(s)
3.1.8
housing
environmental protection of the flow sensor and/or transmitter
3.1.9
secondary containment

housing designed to provide protection to the environment in the event of tube failure

3.1.10
calibrating factor
numerical factor unique to each sensor derived during sensor calibration

Note 1 to entry: The calibrating factor is programmed into the transmitter to enable flowmeter operation.

3.1.11
zero offset
indicated flow when there are zero flow conditions present at the meter

Note 1 to entry: This could be due to mechanical or electrical noise superimposed on the sensor output but equally

could be due to installation effects such as torsional loading caused by improper torqueing of the flange bolts or

temperature extremes creating deflection of the pipeline.
3.1.12
zero stability

variation of the flowmeter output at zero flow after the zero adjustment procedure has been completed,

expressed by the manufacturer as an absolute value in mass per unit time
3.1.13
flashing

phenomenon, which occurs when the line pressure drops to, or below, the vapour pressure of the liquid

Note 1 to entry: This is often due to pressure drops caused by an increase in liquid velocity.

Note 2 to entry: Flashing is not applicable to gases.
3.1.14
cavitation

phenomenon related to and following flashing of liquids if the pressure recovers causing the vapour

bubbles to collapse (implode)
3.1.15
flow rate

quotient of the quantity of fluid passing through the cross-section of the conduit and the time taken for

this quantity to pass through this section
2 © ISO 2015 – All rights reserved
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ISO 10790:2015(E)
3.1.16
mass flow rate
flow rate in which the quantity of fluid is expressed as mass
3.1.17
volume flow rate
flow rate in which the quantity of fluid is expressed as volume
3.2 Definitions from VIM, ISO/IEC Guide 99 (JCGM:2012)
3.2.1
repeatability (condition of measurement)

condition of measurement, out of a set of conditions that includes the same measurement procedure,

same operators, same measuring system, same operating conditions, and same location, and replicate

measurements on the same or similar objects over a short period of time

Note 1 to entry: A condition of measurement is a repeatability condition only with respect to a specified set of

repeatability conditions environmental protection of the flow sensor and/or transmitter.

3.2.2
measurement uncertainty

non-negative parameter characterizing the dispersion of the quantity values being attributed to a

measurand, based on the information used

Note 1 to entry: Measurement uncertainty includes components arising from systematic effects, such as

components associated with corrections and the assigned quantity values of measurement standards, as well as

the definitional uncertainty. Sometimes estimated systematic effects are not corrected for but, instead, associated

measurement uncertainty components are incorporated.

Note 2 to entry: Measurement uncertainty comprises, in general, many components. Some of these can be evaluated

by Type A evaluation of measurement uncertainty from the statistical distribution of the quantity values from

series of measurements and can be characterized by standard deviations. The other components, which can be

evaluated by Type B evaluation of measurement uncertainty, can also be characterized by standard deviations,

evaluated from probability density functions based on experience or other information.

3.2.3
error
measured quantity value minus a reference quantity value

Note 1 to entry: The concept of “measurement error” can be used both a) when there is a single reference quantity

value to refer to, which occurs if a calibration is made by means of a measurement standard with a measured

quantity value having a negligible measurement uncertainty or if a conventional quantity value is given, in which

case the measurement error is known, and b) if a measurand is supposed to be represented by a unique true

quantity value or a set of true quantity values of negligible range, in which case the measurement error is not

known.
3.2.4
cali
...

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