ISO/TR 19884-3:2026

Technical
Report
ISO/TR 19884-3
First edition
Gaseous hydrogen — Pressure
2026-08
vessels for stationary storage —
Part 3:
Pressure cycle test data to
demonstrate partial pressure cycle
estimation methods
Reference number
© ISO 2026
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ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Goodman diagram based method . 2
4.1 S-N diagram .2
4.2 Equivalent pressure cycling .3
4.3 Goodman diagram .4
5 Exponential formula based method . 5
5.1 Formula of cycle life extension by partial pressure cycle .5
5.2 Pressure-cycle test data to determine index .6
5.2.1 General .6
5.2.2 Specification of vessel .6
5.2.3 Hydraulic cycle test conditions .6
5.2.4 Cycle tests results .7
5.2.5 Determination of index .7
5.2.6 Finite element analysis .8
Bibliography .10

iii
Foreword
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This document was prepared by Technical Committee 197, Hydrogen technologies.
A list of all parts in the ISO 19884 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
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iv
Introduction
A much higher level of long-term reliability is required for a pressure vessel in stationary use compared
to on-board use, as the risk of a serious incident in the event of a vessel rupture is significantly higher.
Reliability is ensured through full-pressure cycle testing in accordance with the performance-based
[1]
standard, ISO 19884-1 . One of the primary objectives of utilizing stationary vessels is to accumulate
hydrogen pressure quickly prior to refuelling vehicles. That is why the pressure of a stationary vessel never
decreases to zero in actual use. The expected pressurizing time-history is between the design pressure and
70% of the design pressure, that is, a partial pressure cycle, for which a longer cycle life is expected than
the full pressure cycle life. The cycle life extension by the partial pressure cycle seems applicable to other
high-pressure hydrogen equipment, such as tubes. Cycle life extension is rather a matter of maintenance for
reliable performance. The authority with jurisdiction needs to be convinced that the vessel can be relied
upon for a period longer than the nameplate life. This document presents candidate methods for estimating
cycle life extension through partial pressure cycling for authorities and users, enabling hydrogen stations
to be operated and managed efficiently and safely. This document presents the currently available methods
and the test data to support them. However, this document is not intended to inhibit the advancement of new
technologies that are presently being developed or used in the market, or those yet to emerge. As these new
technologies mature, they will be added in future revisions of this document.

v
Technical Report ISO/TR 19884-3:2026(en)
Gaseous hydrogen — Pressure vessels for stationary
storage —
Part 3:
Pressure cycle test data to demonstrate partial pressure cycle
estimation methods
1 Scope
This document describes detailed methods for evaluating cycle life extension by partial pressure cycles with
necessary conditions and example data of their application.
Two methods for evaluating cycle life extension by partial pressure cycles based on the Goodman diagram
[1]
and exponential formula are presented in ISO 19884-1 . These methods do not rely on fracture mechanical
[1]
methodology but on pressurizing cycle test data, since the framework of ISO 19884-1 is constructed on
performance demonstrated by pressurizing cycle test data in hydrogen.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions 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
Class A material
material known to have no significant or unanticipated changes in its performance or mechanical properties
when exposed to gaseous hydrogen under the listed service conditions
3.2
design pressure
pressure used in the design of the vessel for the purposes of establishing the minimum thickness of the
pressure shell for the stated cycle life and service conditions
3.3
full pressure cycle
cycle of pressure amplitude greater than 100% of the design pressure (3.2) to less than 10% of the design
pressure (3.2)
3.4
full pressure cycle life
maximum number of full pressure cycles in hydrogen service that the pressure vessel is designed to
withstand in service
3.5
mean stress
average of the maximum value and the minimum value of repeated stress
3.6
partial pressure cycle
cycle of pressure amplitude smaller than full pressure cycle (3.3) keeping the maximum pressure lower than
or equal to the design pressure (3.2)
3.7
partial pressure cycle life
maximum number of partial pressure cycles (3.6) that the pressure vessel is designed to withstand in
hydrogen service
3.8
pressure differential
difference between the maximum value and the minimum value of repeated pressure
3.9
stress amplitude
half (1/2) of the difference between the maximum value and the minimum value of repeated stress
4 Goodman diagram based method
4.1 S-N diagram
The S-N diagram has been commonly used for the prediction of fatigue life of metallic specimens. The
Goodman diagram has also been employed to take into account the effect of the mean stress of the stress
cycle on the fatigue life of the specimen. The Miner’s rule has been regarded as valid for the fatigue life
prediction of the specimen in the case of variational stress amplitude. These methods have been developed
in the research of fatigue life of metals, especially of steel. In line with the research and development history
of fatigue life, these methods seem fit for Type 1 pressure vessels, Type 2 pressure vessels, and Type 3
pressure vessels, where the critical failure modes are fatigue crack penetration in the metallic shell. The
merit of these methods can be applied to Type 4 pressure vessels, which consist of a metallic boss, a plastic
liner, and a composite.
The pressure vessel manufacturer is responsible for developing the S-N diagram using the same materials
and manufacturing approach used for the Type 4 pressure vessels. As this is an S-N diagram to evaluate
fatigue characteristics of the composite, the failure mode needs to be consistent, e.g. always composite
failure for a Type 4 pressure vessel (i.e. burst, not liner leakage).
The following steps must be used for a Type 4 vessel:
a) Establish the mean burst pressure of a vessel for which an S -N diagram is to be developed. A minimum
of 4 units of the vessel is required to achieve this. Plot this point as 100 % stress, 1 cycle on the S-N
diagram.
b) Cycle a minimum of 4 units from no more than 10 % of the design pressure to a first specified pressure
level for which the stress is known. Plot this point on the S-N diagram. The S value will be a stress
relative to the mean burst, and the
...