ISO 12101:2025

Industrial valves — Measurement, test and qualification procedures for fugitive emissions — Classification system and qualification procedures for type testing of stem seals for valves

This document covers the type testing of valve stem seals using a test fixture that is designed and fully defined to be representative of the performance of a valve using similar geometry. This document is applicable to stem seals for multi-turn, linear and quarter turn valves. It is intended to provide comparative type test results confirming the performance of seal manufacturers’ stem seal designs. This document is not intended to replace type testing of complete valve assemblies or valve production testing. Compliance with this document is not intended to be a mandatory qualification test to be completed for a stem seal design prior to testing a valve to the requirements of ISO 15848-1. Compressible seals with and without live loading, elastomers and pressure energized seals are in the scope of this document. Corrosion tests are not included in this document.

Robinetterie industrielle — Mesurage, essais et modes opératoires de qualification pour émissions fugitives — Système de classification et modes opératoires de qualification pour les essais de type des dispositifs d'étanchéité de la tige des appareils de robinetterie

General Information

• Status: Published
• Publication Date: 12-Jun-2025
• ICS: 23.060.01 - Valves in general
• Technical Committee: ISO/TC 153 - Valves
• Drafting Committee: ISO/TC 153 - Valves
• Current Stage: 6060 - International Standard published
• Start Date: 13-Jun-2025
• Due Date: 16-Jun-2025
• Completion Date: 13-Jun-2025

Standards Content (Sample)

International
Standard
ISO 12101
First edition
Industrial valves — Measurement,
2025-06
test and qualification procedures
for fugitive emissions —
Classification system and
qualification procedures for type
testing of stem seals for valves
Robinetterie industrielle — Mesurage, essais et modes
opératoires de qualification pour émissions fugitives — Système
de classification et modes opératoires de qualification pour les
essais de type des dispositifs d'étanchéité de la tige des appareils
de robinetterie
Reference number
© ISO 2025
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Published in Switzerland
ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Type test . 2
4.1 Test facility .2
4.2 Stem seal type .3
4.2.1 General .3
4.2.2 Adjustable sealing (compression) .3
4.2.3 Non-adjustable sealing stacks: spring and pressure energized seals .4
4.2.4 Non-adjustable sealing: elastomers .5
4.3 Test fixtures .6
4.3.1 General .6
4.3.2 Preparation of a valve stem seal to be tested .6
4.3.3 Test fluid .6
4.3.4 Test temperature . .7
4.3.5 Leakage measurement .8
4.4 Test procedures .9
4.4.1 Safety rules .9
4.4.2 Test equipment .9
4.4.3 Stem seal adjustment.9
4.4.4 Test description .10
5 Performance classes .12
5.1 Classification criteria . 12
5.2 Tightness classes . 13
5.2.1 Definition . 13
5.2.2 Helium as test fluid . 13
5.2.3 Methane as test fluid . 13
5.2.4 Correlations . 13
5.3 Endurance classes.14
5.3.1 Mechanical-cycle classes simulating isolating valves stem sealing .14
5.3.2 Mechanical-cycle classes for control valve stem sealing . 15
5.3.3 Stem movement .16
5.4 Temperature range .16
5.5 Stem seal performance class designation .17
6 Test report . 17
7 Extension of qualification to untested stem seals .20
Annex A (informative) Test fixture constructions example .21
Bibliography .24

iii
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
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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 document 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).
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This document was prepared by Technical Committee ISO/TC 153, Valves.
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
Introduction
The objective of this document is to establish test methods to evaluate the performance of different designs
and constructions of stem sealing for valves in order to reduce fugitive emissions.
The results from the testing provide a means of classification and qualification under various test conditions.
This classification will help valve manufacturers to choose a suitable stem seal system to allow valve testing
in accordance with ISO 15848-1.
The procedures of this document can only be used with the application of necessary precautions for testing
with flammable or inert gas at temperature and under pressure.

v
International Standard ISO 12101:2025(en)
Industrial valves — Measurement, test and qualification
procedures for fugitive emissions — Classification system and
qualification procedures for type testing of stem seals for valves
1 Scope
This document covers the type testing of valve stem seals using a test fixture that is designed and fully
defined to be representative of the performance of a valve using similar geometry.
This document is applicable to stem seals for multi-turn, linear and quarter turn valves. It is intended to
provide comparative type test results confirming the performance of seal manufacturers’ stem seal designs.
This document is not intended to replace type testing of complete valve assemblies or valve production
testing.
Compliance with this document is not intended to be a mandatory qualification test to be completed for a
stem seal design prior to testing a valve to the requirements of ISO 15848-1.
Compressible seals with and without live loading, elastomers and pressure energized seals are in the scope
of this document.
Corrosion tests are not included in this document.
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 15848-1:2015, Industrial valves — Measurement, test and qualification procedures for fugitive emissions —
Part 1: Classification system and qualification procedures for type testing of valves
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 15848-1 and the following apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
live loading
application of a load to the gland follower of adjustable compression stem seals using a stored energy device
such as a spring
3.2
quarter-turn
...