Hydraulic fluid power -- Measurement techniques

This document establishes procedures for measuring the average steady-state pressure in a hydraulic fluid power conduit.
It is applicable to the measurement of average steady-state pressure in closed conduits with inside diameters greater than 3 mm, transmitting hydraulic fluid power with average fluid velocities less than 25 m/s and average steady-state static pressures less than 70 MPa.
It is not applicable to sensors which are flush mounted with, or an integral part of, the closed fluid conduit wall.
It provides the formulae for estimating the total uncertainty in a given pressure measurement.

Transmissions hydrauliques -- Techniques de mesurage

Fluidna tehnika - Hidravlika - Merilna tehnika

General Information

Status
Published
Publication Date
09-Jun-2021
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
01-Jun-2021
Due Date
06-Aug-2021
Completion Date
10-Jun-2021

RELATIONS

Buy Standard

Standard
SIST ISO 9110-2:2021
English language
15 pages
sale 10% off
Preview
sale 10% off
Preview

e-Library read for
1 day
Standard
ISO 9110-2:2020 - Hydraulic fluid power -- Measurement techniques
English language
10 pages
sale 15% off
Preview
sale 15% off
Preview

Standards Content (sample)

SLOVENSKI STANDARD
SIST ISO 9110-2:2021
01-julij-2021
Nadomešča:
SIST ISO 9110-2:1997
Fluidna tehnika - Hidravlika - Merilna tehnika
Hydraulic fluid power -- Measurement techniques
Transmissions hydrauliques -- Techniques de mesurage
Ta slovenski standard je istoveten z: ISO 9110-2:2020
ICS:
23.100.01 Hidravlični sistemi na splošno Fluid power systems in
general
SIST ISO 9110-2:2021 en

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
SIST ISO 9110-2:2021
---------------------- Page: 2 ----------------------
SIST ISO 9110-2:2021
INTERNATIONAL ISO
STANDARD 9110-2
Second edition
2020-05
Hydraulic fluid power — Measurement
techniques —
Part 2:
Measurement of average steady-state
pressure in a closed conduit
Transmissions hydrauliques — Techniques de mesurage —
Partie 2: Mesurage de la pression moyenne dans un conduit fermé en
régime permanent
Reference number
ISO 9110-2:2020(E)
ISO 2020
---------------------- Page: 3 ----------------------
SIST ISO 9110-2:2021
ISO 9110-2:2020(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2020

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may

be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting

on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address

below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2020 – All rights reserved
---------------------- Page: 4 ----------------------
SIST ISO 9110-2:2021
ISO 9110-2:2020(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

Introduction ..................................................................................................................................................................................................................................v

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

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

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

4 Measuring instrument selection .......................................................................................................................................................... 1

5 Pressure taps ............................................................................................................................................................................................................ 3

6 General procedure .............................................................................................................................................................................................. 6

7 Total measurement uncertainty ........................................................................................................................................................... 9

Bibliography .............................................................................................................................................................................................................................10

© ISO 2020 – All rights reserved iii
---------------------- Page: 5 ----------------------
SIST ISO 9110-2:2021
ISO 9110-2:2020(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 of the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO's adherence to the

World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see www .iso .org/

iso/ foreword .html.

This document was prepared by Technical Committee ISO/TC 131, Fluid power systems, Subcommittee

SC 8, Product testing.

This second edition cancels and replaces the first edition (ISO 9110-2:1990), which has been technically

revised. The main changes compared to the previous edition are as follows:
— the list of normative references has been revised;
— additional terms and definitions have been added;

— the evaluation of the readability of measuring instruments has been deleted and moved to ISO 9110-1;

— the calibration of working instruments has been deleted and moved to ISO 9110-1;

— the selection and installation of test equipment has been revised and combined and test data

acquisition has been renamed as measuring instrument selection;
— total measurement uncertainty has been added.
A list of all parts in the ISO 9110 series can be found on the ISO website.

Any feedback or questions on this document should be directed to the user’s national standards body. A

complete listing of these bodies can be found at www .iso .org/ members .html.
iv © ISO 2020 – All rights reserved
---------------------- Page: 6 ----------------------
SIST ISO 9110-2:2021
ISO 9110-2:2020(E)
Introduction

Universal and standardized techniques for the measurement of pressure are required for accurate and

repeatable evaluation of fluid power systems. The purpose of this document is to present recommended

practices for the measurement of average steady-state pressure in hydraulic fluid power systems. This

document is intended for use in conjunction with ISO 9110-1.
© ISO 2020 – All rights reserved v
---------------------- Page: 7 ----------------------
SIST ISO 9110-2:2021
---------------------- Page: 8 ----------------------
SIST ISO 9110-2:2021
INTERNATIONAL STANDARD ISO 9110-2:2020(E)
Hydraulic fluid power — Measurement techniques —
Part 2:
Measurement of average steady-state pressure in a
closed conduit
1 Scope

This document establishes procedures for measuring the average steady-state pressure in a hydraulic

fluid power conduit.

It is applicable to the measurement of average steady-state pressure in closed conduits with inside

diameters greater than 3 mm, transmitting hydraulic fluid power with average fluid velocities less than

25 m/s and average steady-state static pressures less than 70 MPa.

It is not applicable to sensors which are flush mounted with, or an integral part of, the closed fluid

conduit wall.

It provides the formulae for estimating the total uncertainty in a given pressure measurement.

2 Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements of this document. For dated references, only the edition cited applies. For

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

ISO 5598, Fluid power systems and components — Vocabulary

ISO 9110-1, Hydraulic fluid power — Measurement techniques — Part 1: General measurement principles

3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 5598 and the following apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
tare pressure differential

pressure loss between the pressure tapping points as generated by the test circuit exclusive of the

component under test
4 Measuring instrument selection
4.1 The following subclauses shall be evaluated in accordance with ISO 9110-1.
© ISO 2020 – All rights reserved 1
---------------------- Page: 9 ----------------------
SIST ISO 9110-2:2021
ISO 9110-2:2020(E)

4.2 A complete calibration on measuring instruments which have not been previously calibrated shall

be conducted. Gage or absolute pressure instruments are calibrated following established procedures

using a traceable reference standard. The reference standard used shall be recorded.

Differential pressure instruments should be calibrated at the line pressures corresponding to their

application by pressurizing both instrument ports simultaneously. If bidirectional pressures are to be

measured, calibration should encompass both the positive and negative measurement quadrants of the

instrument.

If this is not practical or the differential pressure instrument is subject to varying line pressures in the

measurement situation, include the maximum expected value of the line pressure effect as a standard

uncertainty contributing term in computing the total measurement uncertainty in Clause 7.

Perform an intermediate instrument calibration as required by the measurement class specified.

4.3 Evaluate the readability uncertainty of the readout device to which the measuring instrument is

connected or equipped.

4.4 Each measuring instrument shall be described by an uncertainty model, which is derived from the

calibration results. Evaluate the calibration uncertainty.

4.5 Each measuring instrument shall be supported by calibration records or calibration database and

should have a calibration label attached. See ISO 9110-1:2020, 6.2.12.

4.6 Consider influencing environmental factors in order to minimize their standard uncertainty

contribution. Environmental conditions usually limit the usefulness of instruments because they are

not designed to operate under diverse operating conditions of temperature, vibration or supply voltage

variations, for example. Consider environmental factors carefully since they often are the largest

uncertainty contributors.

With knowledge of the instrument operating environment and the instrument manufacturer’s

specifications, environmental factors can be minimized or evaluated. Either correct for or include the

uncertainty contribution of environmental factors in computing the total measurement uncertainty in

Clause 7.
2 © ISO 2020 – All rights reserved
---------------------- Page: 10 ----------------------
SIST ISO 9110-2:2021
ISO 9110-2:2020(E)
5 Pressure taps

5.1 Select and install one of the following types of pressure taps. Types 1 and 2 are constructed in

accordance with Figure 1 and Table 1. The Type 3 tap consists of a construction other than Type 1 or 2.

NOTE Drawing is not to scale.
Figure 1 — Pressure tap hole construction
Table 1 — Pressure tap hole construction
Characteristic Description Requirement
C1 Inside diameter Application Specific
C2 Fluid conductor wall thickness Application Specific
C3 Tap hole diameter C2 / C3 ≥ 1,5
C4 Centre line of tap hole diameter (C4) shall meet conductor
Tap hole centre line
centre line and be normal to it.
C5 Corner radius Corner radius R = 1/8 (C3).
max
C6 Corner break Break sharp edge

More than one pressure tap hole is permitted, but only one may be used in the measurement situation

(not a piezometer ring). The tap hole should not be situated on the lowest point of the fluid conductor

when fluid contamination effects are significant. The fabrication technique used for connecting the

fitting to the fluid conductor is optional provided the geometric requirements of Figure 1 are adhered to.

a) Type 1 – This tap is constructed by drilling a hole into a straight piece of the fluid conductor and

shall be free of all visible burrs.
b) Type 2 –
...

INTERNATIONAL ISO
STANDARD 9110-2
Second edition
2020-05
Hydraulic fluid power — Measurement
techniques —
Part 2:
Measurement of average steady-state
pressure in a closed conduit
Transmissions hydrauliques — Techniques de mesurage —
Partie 2: Mesurage de la pression moyenne dans un conduit fermé en
régime permanent
Reference number
ISO 9110-2:2020(E)
ISO 2020
---------------------- Page: 1 ----------------------
ISO 9110-2:2020(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2020

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may

be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting

on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address

below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2020 – All rights reserved
---------------------- Page: 2 ----------------------
ISO 9110-2:2020(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

Introduction ..................................................................................................................................................................................................................................v

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

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

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

4 Measuring instrument selection .......................................................................................................................................................... 1

5 Pressure taps ............................................................................................................................................................................................................ 3

6 General procedure .............................................................................................................................................................................................. 6

7 Total measurement uncertainty ........................................................................................................................................................... 9

Bibliography .............................................................................................................................................................................................................................10

© ISO 2020 – All rights reserved iii
---------------------- Page: 3 ----------------------
ISO 9110-2:2020(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 of the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO's adherence to the

World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see www .iso .org/

iso/ foreword .html.

This document was prepared by Technical Committee ISO/TC 131, Fluid power systems, Subcommittee

SC 8, Product testing.

This second edition cancels and replaces the first edition (ISO 9110-2:1990), which has been technically

revised. The main changes compared to the previous edition are as follows:
— the list of normative references has been revised;
— additional terms and definitions have been added;

— the evaluation of the readability of measuring instruments has been deleted and moved to ISO 9110-1;

— the calibration of working instruments has been deleted and moved to ISO 9110-1;

— the selection and installation of test equipment has been revised and combined and test data

acquisition has been renamed as measuring instrument selection;
— total measurement uncertainty has been added.
A list of all parts in the ISO 9110 series can be found on the ISO website.

Any feedback or questions on this document should be directed to the user’s national standards body. A

complete listing of these bodies can be found at www .iso .org/ members .html.
iv © ISO 2020 – All rights reserved
---------------------- Page: 4 ----------------------
ISO 9110-2:2020(E)
Introduction

Universal and standardized techniques for the measurement of pressure are required for accurate and

repeatable evaluation of fluid power systems. The purpose of this document is to present recommended

practices for the measurement of average steady-state pressure in hydraulic fluid power systems. This

document is intended for use in conjunction with ISO 9110-1.
© ISO 2020 – All rights reserved v
---------------------- Page: 5 ----------------------
INTERNATIONAL STANDARD ISO 9110-2:2020(E)
Hydraulic fluid power — Measurement techniques —
Part 2:
Measurement of average steady-state pressure in a
closed conduit
1 Scope

This document establishes procedures for measuring the average steady-state pressure in a hydraulic

fluid power conduit.

It is applicable to the measurement of average steady-state pressure in closed conduits with inside

diameters greater than 3 mm, transmitting hydraulic fluid power with average fluid velocities less than

25 m/s and average steady-state static pressures less than 70 MPa.

It is not applicable to sensors which are flush mounted with, or an integral part of, the closed fluid

conduit wall.

It provides the formulae for estimating the total uncertainty in a given pressure measurement.

2 Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements of this document. For dated references, only the edition cited applies. For

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

ISO 5598, Fluid power systems and components — Vocabulary

ISO 9110-1, Hydraulic fluid power — Measurement techniques — Part 1: General measurement principles

3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 5598 and the following apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
tare pressure differential

pressure loss between the pressure tapping points as generated by the test circuit exclusive of the

component under test
4 Measuring instrument selection
4.1 The following subclauses shall be evaluated in accordance with ISO 9110-1.
© ISO 2020 – All rights reserved 1
---------------------- Page: 6 ----------------------
ISO 9110-2:2020(E)

4.2 A complete calibration on measuring instruments which have not been previously calibrated shall

be conducted. Gage or absolute pressure instruments are calibrated following established procedures

using a traceable reference standard. The reference standard used shall be recorded.

Differential pressure instruments should be calibrated at the line pressures corresponding to their

application by pressurizing both instrument ports simultaneously. If bidirectional pressures are to be

measured, calibration should encompass both the positive and negative measurement quadrants of the

instrument.

If this is not practical or the differential pressure instrument is subject to varying line pressures in the

measurement situation, include the maximum expected value of the line pressure effect as a standard

uncertainty contributing term in computing the total measurement uncertainty in Clause 7.

Perform an intermediate instrument calibration as required by the measurement class specified.

4.3 Evaluate the readability uncertainty of the readout device to which the measuring instrument is

connected or equipped.

4.4 Each measuring instrument shall be described by an uncertainty model, which is derived from the

calibration results. Evaluate the calibration uncertainty.

4.5 Each measuring instrument shall be supported by calibration records or calibration database and

should have a calibration label attached. See ISO 9110-1:2020, 6.2.12.

4.6 Consider influencing environmental factors in order to minimize their standard uncertainty

contribution. Environmental conditions usually limit the usefulness of instruments because they are

not designed to operate under diverse operating conditions of temperature, vibration or supply voltage

variations, for example. Consider environmental factors carefully since they often are the largest

uncertainty contributors.

With knowledge of the instrument operating environment and the instrument manufacturer’s

specifications, environmental factors can be minimized or evaluated. Either correct for or include the

uncertainty contribution of environmental factors in computing the total measurement uncertainty in

Clause 7.
2 © ISO 2020 – All rights reserved
---------------------- Page: 7 ----------------------
ISO 9110-2:2020(E)
5 Pressure taps

5.1 Select and install one of the following types of pressure taps. Types 1 and 2 are constructed in

accordance with Figure 1 and Table 1. The Type 3 tap consists of a construction other than Type 1 or 2.

NOTE Drawing is not to scale.
Figure 1 — Pressure tap hole construction
Table 1 — Pressure tap hole construction
Characteristic Description Requirement
C1 Inside diameter Application Specific
C2 Fluid conductor wall thickness Application Specific
C3 Tap hole diameter C2 / C3 ≥ 1,5
C4 Centre line of tap hole diameter (C4) shall meet conductor
Tap hole centre line
centre line and be normal to it.
C5 Corner radius Corner radius R = 1/8 (C3).
max
C6 Corner break Break sharp edge

More than one pressure tap hole is permitted, but only one may be used in the measurement situation

(not a piezometer ring). The tap hole should not be situated on the lowest point of the fluid conductor

when fluid contamination effects are significant. The fabrication technique used for connecting the

fitting to the fluid conductor is optional provided the geometric requirements of Figure 1 are adhered to.

a) Type 1 – This tap is constructed by drilling a hole into a straight piece of the fluid conductor and

shall be free of all visible burrs.

b) Type 2 – It is constructed in the same manner as Type 1, but either has visible burrs or the interior

edge of hole C3 cannot be verified as being free of all visible burrs.

c) Type 3 – It is a tap consisting of a construction other than that described in a) and b). For example,

a tap which consists of a commercial type straight fitting, tee, or cross, often used in applications

utilizing hose or steel tube conduits to implement a tap, would be
...

Questions, Comments and Discussion

Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.