FprEN IEC 63203-401-1:2026

• Status: Not Published
• Publication Date: 03-Mar-2027
• ICS: 31.020 - Electronic components in general
• Technical Committee: CLC/SR 124 - Wearable Electronic Devices and Technologies
• Current Stage: 5020 - Vote circulated - Formal Approval
• Start Date: 23-Oct-2026
• Completion Date: 23-Oct-2026
• Ref Project: kSIST FprEN IEC 63203-401-1:2026 - Wearable electronic devices and technologies - Part 401-1: Devices and systems: functional elements - Measurement method of the stretchable resistive strain sensor

• Revises: EN IEC 63203-401-1:2023 - Wearable electronic devices and technologies - Part 401-1: Devices and systems: functional elements - Evaluation method of the stretchable resistive strain sensor
• Effective Date: 12-Dec-2023

FprEN IEC 63203-401-1:2026 is a CLC document based on IEC 63203-401-1 for wearable electronic devices and technologies. It specifies a measurement method for stretchable resistive strain sensors, including how to determine the linear area, strain limits, and gauge factor for sensors that undergo large deformations. The document is aimed at engineers, test laboratories, and suppliers who need a common way to measure and compare sensor-device performance.

What does FprEN IEC 63203-401-1:2026 specify?

FprEN IEC 63203-401-1:2026 specifies how to measure stretchable resistive strain sensors for large deformations. The focus is on sensor devices, not sensor materials, and the method is not intended for conventional thin-metal-film strain gauges.

The document is organized into clauses on scope, normative references, terms and definitions, test environments, test specimen, test equipment, test procedure, and report, followed by a bibliography. That structure tells the reader where to find the test conditions, how to run the measurement, and what to record at the end.

What are the key requirements of FprEN IEC 63203-401-1:2026?

FprEN IEC 63203-401-1:2026 is built around a controlled tensile test that relates strain to both mechanical response and resistance change. In practice, the user measures the sensor under defined conditions, identifies the usable linear range, and reports the result in a consistent format.

Test environment and specimen preparation

Clause 4 requires the test to be carried out at 23 °C ± 2 °C and 50 % ± 10 % relative humidity, matching ISO 291 class 2. This matters because stretchable materials and resistance measurements can shift with temperature and humidity.

Clause 5 requires the sensor device to have at least one terminal or lead wire for resistance measurement and an externally visible marking of the gauge length. The sensor may be a standalone device or may be integrated on the object being measured, so the same method can be used for both product forms.

Clause 5 also warns that the conductive filler network must not be changed irreversibly by stretching. In practice, that means the test must avoid overextension and repeated stretching beyond the sensor’s limit, because permanent changes can invalidate the result.

Test equipment

Clause 6 allows either a horizontal or vertical tensile testing machine, provided the sensor can be deformed longitudinally in a controlled way. For linear-area testing, the machine must be able to measure the elastic deformation area, because the method depends on knowing where reversible behavior ends.

Clause 6 requires a resistance measurement device using either a 2-terminal or 4-terminal method. If the resistance is below 1 kΩ, the 4-terminal method is recommended, which helps reduce measurement error. If response characteristics are being measured, the device needs data recording, with time resolution agreed between the user and supplier.

Clause 6 also requires a non-invasive way to measure gauge length change. A certified ruler or mechanical extensometer is the normal choice, while optical methods such as laser, interference light, camera systems, or digital image correlation can be used when higher accuracy is needed.

How the linear area, strain limit, and gauge factor are determined

Clause 7 says to measure both the stress-strain (S-S) curve and the resistance-versus-strain curve. The mechanical linear region comes from the straight-line part of the S-S curve, and the electrical linear region comes from the straight-line part of the resistance curve.

Clause 7 defines the strain limit from the point where the curve departs from linear behavior by 1.0 %, unless user and supplier agree otherwise. The document then takes the narrower of the mechanical and electrical linear regions as the sensor’s linear area, and the smaller of the two strain limits as the sensor’s strain limit.

Clause 7 also uses the slope in the electrically linear region as the gauge factor. In practice, this gives the user one sensitivity value tied to the part of the curve where the sensor behaves predictably.

The informative text in Clause 7 notes that response delay, creep, and hysteresis can occur in this type of sensor. The document recommends treating these effects in the same way as errors are treated for metal thin-film strain gauges, and suggests keeping later testing within 50 % or less of the strain limit.

What terms does FprEN IEC 63203-401-1:2026 define?

FprEN IEC 63203-401-1:2026 defines a small set of terms that matter for interpretation of the test method.

• Gauge factor - the ratio of resistance change to original resistance, divided by engineering strain along the stretching axis; it expresses sensor sensitivity.
• Gauge length - the length of the strain-sensing area in the measurement direction; it defines the active sensing span.
• Stretchable resistive strain sensor - a sensor that uses resistance change in a conductive material dispersed in a stretchable polymer; it is the device type this method measures.
• Mechanical linear region - the part of the stress-strain behavior that remains straight within the method’s error criterion; it marks reversible mechanical use.
• Electrical linear region - the part of the resistance-versus-strain behavior that remains straight within the method’s error criterion; it marks the range where output tracks strain predictably.
• Strain limit - the smaller of the mechanical and electrical limits; it is the practical upper boundary for the test range.

Who uses FprEN IEC 63203-401-1:2026?

FprEN IEC 63203-401-1:2026 is used by wearables engineers, sensor developers, test laboratories, quality teams, and suppliers of electronic components and wearable systems. They use it to verify sensor behavior, compare products, set test conditions, and document linear range, strain limit, and gauge factor in a common way.

What changed in FprEN IEC 63203-401-1:2026 from the previous edition?

FprEN IEC 63203-401-1:2026 is identified as identical to prEN IEC 63203-401-1:2025. The introduction says that ED2 is a fundamental review of the test method and that it was revised to resolve earlier confusion between evaluation of sensor devices and evaluation of sensor materials.

Which standards are used with FprEN IEC 63203-401-1:2026?

FprEN IEC 63203-401-1:2026 cites ISO 291:2008 as a normative reference, and uses it to set the standard atmosphere for conditioning and testing. The bibliography also points to IEC 63203-101-1:2021 for terminology in wearable electronic devices and technologies, and ASTM E251-92 for metallic bonded resistance strain gage performance characteristics.

What does the FprEN IEC 63203-401-1:2026 document contain?

FprEN IEC 63203-401-1:2026 contains the test environment, specimen requirements, equipment requirements, test procedure, and report items needed to measure a stretchable resistive strain sensor. It includes two example figures showing typical sensor construction, with substrate, sensing material, electrode, lead wire, sensing area, and gauge length.

The procedure explains how to build the S-S curve, how to identify the mechanical and electrical linear regions, and how to determine the strain limits and gauge factor. The informative part discusses response delay, creep, and hysteresis, which are important when judging real sensor behavior under repeated deformation.

The report clause lists the results that should be recorded: sensor identification, environment, mechanical and electrical linear regions and strain limits, overall linear range and strain limit, and gauge factor. That makes the document useful for testing, comparison, and technical reporting.

SLOVENSKI STANDARD
oSIST prEN IEC 63203-401-1:2026
01-februar-2026
Nosljive elektronske naprave in tehnologije - 401-1. del: Naprave in sistemi:
Funkcionalni elementi - Merilna metoda raztegljivega uporovnega senzorja
napetosti
Wearable electronic devices and technologies - Part 401-1: Devices and systems:
Functional elements - Measurement method of the stretchable resistive strain sensor
Technologies et dispositifs électroniques prêt-à-porter - Partie 401-1: Dispositifs et
systèmes: éléments de fonctionnement - Méthode de mesure du capteur de déformation
extensible de type résistif
Ta slovenski standard je istoveten z: prEN IEC 63203-401-1:2025
ICS:
31.020 Elektronske komponente na Electronic components in
splošno general
oSIST prEN IEC 63203-401-1:2026 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

oSIST prEN IEC 63203-401-1:2026

oSIST prEN IEC 63203-401-1:2026
124/359/CDV
COMMITTEE DRAFT FOR VOTE (CDV)

PROJECT NUMBER:
IEC 63203-401-1 ED2
DATE OF CIRCULATION: CLOSING DATE FOR VOTING:
2025-12-05 2026-02-27
SUPERSEDES DOCUMENTS:
124/336/CD, 124/352/CC
IEC TC 124 : WEARABLE ELECTRONIC DEVICES AND TECHNOLOGIES
SECRETARIAT: SECRETARY:
Korea, Republic of Mr Jae Yeong Park
OF INTEREST TO THE FOLLOWING COMMITTEES: HORIZONTAL FUNCTION(S):
SC 47F
ASPECTS CONCERNED:
SUBMITTED FOR CENELEC PARALLEL VOTING NOT SUBMITTED FOR CENELEC PARALLEL VOTING
Attention IEC-CENELEC parallel voting
The attention of IEC National Committees, members of
CENELEC, is drawn to the fact that this Committee Draft
for Vote (CDV) is submitted for parallel voting.
The CENELEC members are invited to vote through the
CENELEC online voting system.
This document is still under study and subject to change. It should not be used for reference purposes.
Recipients of this document are invited to submit, with their comments, notification of any relevant patent rights of
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Recipients of this document are invited to submit, with their comments, notification of any relevant “In Some
Countries” clauses to be included should this proposal proceed. Recipients are reminded that the CDV stage is
the final stage for submitting ISC clauses. (SEE AC/22/2007 OR NEW GUIDANCE DOC).

TITLE:
Wearable electronic devices and technologies - Part 401-1: Devices and systems: functional
elements - Measurement method of the stretchable resistive strain sensor

PROPOSED STABILITY DATE: 2031
NOTE FROM TC/SC OFFICERS:
download this electronic file, to make a copy and to print out the content for the sole purpose of preparing National
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oSIST prEN IEC 63203-401-1:2026
IEC CD 63203-401-1 ED2 © IEC 2025
1 CONTENTS
3 FOREWORD . 2
4 1 Scope . 5
5 2 Normative references . 5
6 3 Terms and definitions . 5
7 4 Test environments . 6
8 5 Test specimen . 6
9 5.1 Principle and precaution . 6
10 5.2 Sensor device to be measured . 6
11 6 Test equipment . 7
12 6.1 Tensile testing machine . 7
13 6.2 Resistance measurement device . 8
14 6.3 Length measurement means . 8
15 7 Test procedure . 8
16 7.1 Outline . 8
17 7.2 Linear region, strain limit, gauge factor . 9
18 7.2.1 Tensile test . 9
19 7.2.2 Mechanical linear region and mechanical strain limit . 9
20 7.2.3 Electrical linear region and mechanical strain limit . 9
21 7.2.4 Linear area and strain limit of strain sensor . 9
22 7.2.5 Gauge factor . 9
23 7.3 Error (informative) . 9
24 8 Report . 10
25 Bibliography . 11
oSIST prEN IEC 63203-401-1:2026
IEC CD 63203-401-1 ED2 © IEC 2025
28 INTERNATIONAL ELECTROTECHNICAL COMMISSION
29 ____________
31 WEARABLE ELECTRONIC DEVICES AND TECHNOLOGIES –
33 Part 401-1: Devices and systems: functional elements –
34 Measurement method of the stretchable resistive strain sensor
36 FOREWORD
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69 IEC 63203-401-1 has been prepared by IEC technical committee 124: Wearable electronic
70 devices and technologies. It is an International Standard.
71 The text of this International Standard is based on the following documents:
Draft Report on voting
124/223/FDIS 124/239/RVD
73 Full information on the voting for its approval can be found in the report on voting indicated in
74 the above table.
75 The language used for the development of this International Standard is English.
oSIST prEN IEC 63203-401-1:2026
IEC CD 63203-401-1 ED2 © IEC 2025
76 This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
77 accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
78 at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
79 described in greater detail at www.iec.ch/publications.
80 A list of all parts in the IEC 63203 series, published under the general title Wearable electronic
81 devices and technologies, can be found on the IEC website.
82 The committee has decided that the contents of this document will remain unchanged until the
83 stability date indicated on the IEC website under webstore.iec.ch in the data related to the
84 specific document. At this date, the document will be
85 • reconfirmed,
86 • withdrawn, or
87 • revised.
IMPORTANT – The "colour inside" logo on the cover page of this document indicates
that it contains colours which are considered to be useful for the correct understanding
of its contents. Users should therefore print this document using a colour printer.
oSIST prEN IEC 63203-401-1:2026
IEC CD 63203-401-1 ED2 © IEC 2025
91 Introduction
92 Generally, strain sensors (strain gauges) utilize changes in the electrical resistance of a thin
93 copper-nickel alloy coating formed on a polymer film such as PET film. The strain sensor is
94 bonded to the object to be measured, and the strain in the strain sensor caused by the strain in
95 the object to be measured is detected as a change in resistance of the thin metal film.
96 As is obvious from the sensor’s material and structure, the object to be measured is mainly a
97 high elastic modulus member such as a metal material, the amount of strain detected is very
98 small, and the resistance change that is the output is also small. Therefore, it is common to
99 detect resistance changes as voltage changes using a Wheatstone bridge circuit, without
100 directly measuring resistance values. In the range where the relationship between strain change
101 and resistance value change is linear, the proportionality constant between the two is called
102 the gauge factor. Several existing standards are known for gauge factor measurement and are
103 listed in Bibliography.
104 On the other hand, the strain sensor covered by this standard utilizes the change in resistance
105 caused by the deformation of a conductive material in which conductive filler is dispersed in a
106 stretchable polymer material (such as an elastomer).
107 However, compared to the strain sensor using thin metal film described above, the target strain
108 range and resistance value change range are significantly different, so new testing methods for
109 this type of strain sensor are needed. ED1 of this standard was published with unresolved
110 technical issues such as the confusion between evaluation of sensor devices and evaluation of
111 sensor materials.
112 In ED2, the test method has been fundamentally reviewed and revised as a measurement
113 method for sensor devices.
oSIST prEN IEC 63203-401-1:2026
IEC CD 63203-401-1 ED2 © IEC 2025
116 WEARABLE ELECTRONIC DEVICES AND TECHNOLOGIES –
118 Part 401-1: Devices and systems: functional elements –
119 Measurement method of the stretchable resistive strain
...