ISO 23016-2:2026

• Abstract:

  This document specifies a method to test the promotion of the germination of barley seeds, using ultrafine bubble (UFB) water produced from an ultrafine bubble water generating system. The performance of the method is assessed by measuring the ratio of barley seed germination.

• Status: Published
• Publication Date: 30-Jun-2026
• ICS: 07.030 - Physics. Chemistry
• ICS: 65.020.20 - Plant growing
• Technical Committee: ISO/TC 281 - Fine bubble technology
• Drafting Committee: ISO/TC 281/WG 3 - Applications of fine bubble technology
• Current Stage: 6060 - International Standard published
• Start Date: 01-Jul-2026
• Due Date: 17-Aug-2026
• Completion Date: 01-Jul-2026

• Revises: ISO 23016-2:2019 - Fine bubble technology — Agricultural applications — Part 2: Test method for evaluating the promotion of the germination of barley seeds
• Effective Date: 22-Feb-2025

ISO 23016-2:2026 is an ISO International Standard that specifies a test method for evaluating whether ultrafine bubble (UFB) water promotes the germination of barley seeds. It is written for testing UFB generating systems and the UFB water they produce, with performance judged by the germination ratio of the seeds.

What does ISO 23016-2:2026 specify?

ISO 23016-2:2026 specifies a laboratory method for comparing barley seed germination in UFB water and control water made from the same raw water. The standard focuses on one measurable outcome - the germination ratio - so users can assess whether a UFB generating system changes germination behavior in a repeatable way.

The document is organized into clauses on scope, references, terms, testing principle, test subjects, apparatus, environment, procedure, and reporting. It also includes an informative example and a normative limit-sample annex used to judge whether seeds are germinated.

Annex	What it covers
Annex A	Informative example of a laboratory test result and S-curve analysis
Annex B	Normative barley seed limit samples for judging germination

What are the key requirements of ISO 23016-2:2026?

ISO 23016-2:2026 requires the test to use UFB water generated from an ultrafine bubble generating system and control water made from the same distilled raw water. In practice, this means the comparison is controlled, so the result reflects the effect of the UFB water rather than differences in starting water.

Test material and water quality

Clause 5 requires barley seed testing to use UFB water stored in bottles or other containers suitable for preservation and transport, and the UFB generating system must supply the water in the same manner to such containers. The raw water must be distilled water of A2 or higher quality, and the size, quantity, and concentration of UFB in the water shall be measured or given. This matters because the test report needs traceable water quality and UFB characteristics.

Seed preparation and inspection

Clause 8 requires 300 barley seeds per test, selected for uniform size, color, and surface condition using the limit sample in Annex B. The seeds are divided into two groups of 150, then into six bags of 50 seeds each, with three bags for UFB water and three for control water. In practice, this keeps the sample handling consistent and makes the two sections comparable.

Environment and test timing

Clause 7 requires the test water in the beakers to be kept between 20 °C and 30 °C, while the room temperature is maintained at room temperature and the beakers are covered to limit evaporation and contamination. Clause 8 also requires the test period to be set from seed-source information or a preliminary test, with inspection intervals frequent enough to give at least four inspections. That gives enough time points for a meaningful germination curve.

Measurement and result calculation

Clause 4 assesses performance through the germination ratio and a derived quantity called UFB enabled efficiency, P, based on the delay parameter T50 from an S-curve regression. Annex A shows the analysis approach. In practice, this means users do not just count sprouted seeds - they compare the timing of germination between UFB and control sections.

Reporting

Clause 9 requires the report to state the test institution, date, seed type, test subjects, user-adjustable operating parameters for a UFB generating system, environmental conditions, test parameters, UFB enabled efficiency, deviations, and the calculation reference. This makes the result auditable and easier to compare across laboratories.

What terms does ISO 23016-2:2026 define?

• Germination - the appearance of a radicle at least 1 mm long.
• Ultrafine bubble generating system (UFB generating system) - equipment that uses water and air to generate ultrafine bubbles by mechanical action.
• Ultrafine bubble water (UFB water) - water that includes UFB.
• Control water - water used as the control sample for the effect of UFB.
• Raw water - distilled water used as the starting water for both UFB water and control water.
• Germination ratio - the number of germinated seeds observed divided by the total number of seeds tested.
• UFB enabled efficiency, P - the quantity used to express the relative germination delay between UFB and control sections.

Who uses ISO 23016-2:2026?

ISO 23016-2:2026 is used by testing laboratories, developers and manufacturers of UFB generating systems, and organizations evaluating UFB water for agricultural applications. It is also relevant to quality managers and buyers who need a defined way to compare seed-germination performance under controlled conditions.

What changed in ISO 23016-2:2026 from the previous edition?

ISO 23016-2:2026 cancels and replaces ISO 23016-2:2019 as a second edition and states that it is a minor revision. The stated change is the insertion of Table 1 in Clause 5, giving water quality A2 according to JIS K 0557, with six items that were previously in a footnote.

Which standards are used with ISO 23016-2:2026?

• ISO 20480-1 - provides the terminology used for fine bubbles and defines UFB-related terms.
• ISO 20480-2 - gives the categorization of fine-bubble attributes used in the document.
• ISO 18763 - is the source for the germination definition, modified in this standard to refer to a radicle.
• JIS K 0557 - is the basis for the water-quality classification used in Table 1.

What does the ISO 23016-2:2026 document contain?

ISO 23016-2:2026 contains a general testing principle, equipment requirements, environmental conditions, and a step-by-step test procedure for barley seed germination in UFB water and control water. It also describes how to inspect seeds, how often to record results, and how to calculate germination ratio and UFB enabled efficiency.

The document includes a figure showing the test system principle, figures for seed bag arrangement and beaker setup, and a limit-sample figure in Annex B for judging germinated versus non-germinated seeds. Annex A gives an example of laboratory results with S-curve regression and T50-based comparison, which helps users understand the intended analysis and reporting format.

International
Standard
ISO 23016-2
Second edition
Fine bubble technology —
2026-07
Agricultural applications —
Part 2:
Test method for evaluating the
promotion of the germination of
barley seeds
Technologie des fines bulles — Applications agricoles —
Partie 2: Méthode d'essai pour l'évaluation de la promotion de la
germination des graines d'orge
Reference number
© ISO 2026
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
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or ISO’s member body in the country of the requester.
ISO copyright office
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Website: www.iso.org
Published in Switzerland
ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 General testing principle . 2
4.1 General overview of the test system .2
4.2 Assessment of test results .3
5 Test subjects . 4
6 Apparatus and test equipment . 4
6.1 Seeds for germination test .4
6.2 UFB generating system and UFB water .4
6.3 Measurement and observation equipment.5
6.4 Beakers .5
6.5 Constant-temperature water tank .5
6.6 Plastic bags .5
6.7 Test tray and filter paper .5
6.8 Limit sample for inspection .5
6.9 Maintenance of measurement devices and equipment .6
6.9.1 Maintenance .6
6.9.2 Calibration . . .6
7 Test environment . 6
7.1 Temperature conditions .6
7.2 Environmental parameters to be measured .6
8 Test procedure . 6
8.1 Test period and interval between inspections .6
8.2 Seed selection and packing into bags .6
8.3 Use of UFB water and control water .7
8.4 Tray preparation and seed sowing .8
8.5 Inspection and recording .9
9 Test report . 9
Annex A (informative) Example of test result at testing laboratory .10
Annex B (normative) Barley seed limit samples .12
Bibliography .13

iii
Foreword
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This document was prepared by Technical Committee ISO/TC 281, Fine bubble technology.
This second edition cancels and replaces the first edition (ISO 23016-2:2019), of which it constitutes a minor
revision. The changes are as follows:
— Table 1 has been inserted in Clause 5 indicating the water quality of A2, according to JIS K 0557, with six
items originally provided in the footnote.
A list of all parts in the ISO 23016 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
Introduction
Considering the increasing use of fine bubble technology in agriculture, this document has been developed
to establish standards in this area, with particular focus on promoting the germination and growth of barley
seeds.
The use of fine bubble technology in agriculture has been confirmed to benefit various types of agricultural
products and has attracted the interest of various countries. Application of the technology to leafy vegetables
in agriculture is already well-established, and this is being expanded to seed germination and growth as
well. Worldwide as well, standardization of fine bubble technology in the field of agriculture is not only being
spotlighted but is being conducted in practice at a rapid pace. The technology is expected to blossom rapidly.
Fine bubble technology has been applied successfully not only in agriculture but also in the fields of
environmental science, food, marine products, medicine, etc. Wide-ranging progress in standardizing the
technology is being made in these fields. The achievement of standardization in various fields is expected to
result in increased worldwide recognition of fine bubble technology in the future.

v
International Standard ISO 23016-2:2026(en)
Fine bubble technology — Agricultural applications —
Part 2:
Test method for evaluating the promotion of the germination
of barley seeds
1 Scope
This document specifies a method to test the promotion of the germination of barley seeds, using ultrafine
bubble (UFB) water produced from an ultrafine bubble water generating system. The performance of the
method is assessed by measuring the ratio of barley seed germination.
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 20480-1, Fine bubble technology — General principles for usage and measurement of fine bubbles — Part 1:
Terminology
ISO 20480-2, Fine bubble technology — General principles for usage and measurement of fine bubbles — Part 2:
Categorization of the attributes of fine bubbles
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 20480-1 and ISO 20480-2 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
germination
appearance of a radicle of at least 1 mm of length
[1]
[SOURCE: ISO 18763:2016, 3.7, modified — "root" has been replaced by " radicle".]
3.2
ultrafine bubble generating system
UFB generating system
equipment that uses water and air to generate ultrafine bubbles by mechanical action
Note 1 to entry: Ultrafine bubbles (UFB) are bubbles with a diameter of less than 1 µm. See ISO 20480-1.

3.3
ultrafine bubble water
UFB water
water that includes UFB
Note 1 to entry: UFB are defined in ISO 20480-1.
3.4
control water
water for use as a control sample for the effects of UFB
3.5
raw water
distilled water supplied as a raw material for both UFB water (3.3) and control water (3.4)
3.6
test water
either UFB water (3.3) or control water (3.4)
3.7
UFB section
test beaker containing UFB water (3.3) for use in germination tests of barley seeds in UFB water
3.8
control section
test beaker containing control water (3.4) for use in germination tests of barley seeds in control water
3.9
germination ratio
G
ratio of the seeds observed during inspection to have germinated to the total number of seeds provided for
the test
3.10
UFB enabled efficiency
P
quantity measuring the efficiency of UFB for its enhancement in the germinating period
Note 1 to entry: P is defined by Formula (1).
4 General testing principle
4.1 General overview of the test system
UFB water shall be generated through the supply of raw water to the ultrafine bubble generating system.
The UFB water shall be supplied to the UFB section to promote the germination of the barley seeds that
have been supplied to the UFB section. In addition, raw water for control purposes that does not contain
UFB shall be supplied directly to the control section. Figure 1 shows the constitutive principle of the growth
promotion performance test.
Figure 1 — General view of growth promotion performance test system
4.2 Assessment of test results
The germination ratio, G, is obtained by calculating the number of germinated seeds to the number of all
seeds tested for each inspection.
The development of the germination ratio is assumed to be expressed by a specified S-curve regression
[2],[3]
function and a parameter T related to the delay in the germination is to be inferred by the process as
[4]-[10]
described below for each section. The relative difference of the parameter for UFB section to control
section is the measure for the performance of the fine bubble enhanced performance, defined as UFB enabled
efficiency, P, to be reported.
Efficiency, P, is given by Formula (1):
PT controlUTTFB / control (1)
  
50 50 50
where
P is the efficiency;
T (control) is
...