Textiles and textile products - Smart textiles - Definitions, categorisation, applications and standardization needs

This Technical Report provides definitions in the field of "smart" textiles and textile products as well as a categorisation of different types of smart textiles. It describes briefly the current stage of development of these products and their application potential and gives indications on preferential standardization needs.

Textilien und textile Produkte - Intelligente Textilien - Definitionen, Klassifizierung, Anwendungen und Normungsbedarf

Der vorliegende Technische Bericht enthält Begriffe aus dem Bereich der „intelligenten“ Textilien und textilen Erzeugnisse, sowie eine Kategorisierung verschiedener Typen von intelligenten Textilien. In Kurzform werden der aktuelle Entwicklungsstand dieser Erzeugnisse und deren Anwendungsmöglichkeit beschrieben, und es werden Angaben zu vorrangigen Normungsergebnissen gemacht.

Textiles et produits textiles - Textiles intelligents - Définitions, catégorisation, applications et besoins de normalisation

Le présent Rapport technique fournit des définitions dans le domaine des textiles et produits textiles « intelligents », ainsi qu’une catégorisation des différents types de textiles intelligents. Il décrit brièvement l’état actuel de développement de ces produits et leur application potentielle et fournit des indications sur les besoins de normalisation préférentiels.

Tekstilije - Inteligentne tekstilije - Definicije, kategorizacija, uporaba in standardizacijske potrebe

To tehnično poročilo vsebuje definicije na področju »inteligentnih« tekstilij in kategorizacijo različnih vrst inteligentnih tekstilij. Na kratko opisuje trenutno stopnjo razvoja teh izdelkov in potencial za uporabo ter navaja prednostne standardizacijske potrebe.

General Information

Status
Withdrawn
Publication Date
09-Jan-2012
Withdrawal Date
23-Dec-2020
Current Stage
9900 - Withdrawal (Adopted Project)
Start Date
23-Dec-2020
Due Date
15-Jan-2021
Completion Date
24-Dec-2020

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SLOVENSKI STANDARD
SIST-TP CEN/TR 16298:2012
01-februar-2012
Tekstilije - Inteligentne tekstilije - Definicije, kategorizacija, uporaba in
standardizacijske potrebe

Textiles and textile products - Smart textiles - Definitions, categorisation, applications

and standardization needs

Textilien und textile Produkte - Intelligente Textilien - Definitionen, Klassifizierung,

Anwendungen und Normungsbedarf
Ta slovenski standard je istoveten z: CEN/TR 16298:2011
ICS:
59.080.01 Tekstilije na splošno Textiles in general
SIST-TP CEN/TR 16298:2012 en,de

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

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SIST-TP CEN/TR 16298:2012
TECHNICAL REPORT
CEN/TR 16298
RAPPORT TECHNIQUE
TECHNISCHER BERICHT
November 2011
ICS 59.080.99
English Version
Textiles and textile products - Smart textiles - Definitions,
categorisation, applications and standardization needs

Textiles et produits textiles - Textiles intelligents - Textilien und textile Produkte - Intelligente Textilien -

Définitions, catégorisation, applications et besoins de Definitionen, Klassifizierung, Anwendungen und

normalisation Normungsbedarf

This Technical Report was approved by CEN on 24 October 2011. It has been drawn up by the Technical Committee CEN/TC 248.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,

Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland,

Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.

EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: Avenue Marnix 17, B-1000 Brussels

© 2011 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN/TR 16298:2011: E

worldwide for CEN national Members.
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Contents Page

Foreword ..............................................................................................................................................................3

Introduction .........................................................................................................................................................4

1 Scope ......................................................................................................................................................6

2 Terms and definitions ...........................................................................................................................6

3 Functional and smart textile materials ................................................................................................7

3.1 Functional textile materials ..................................................................................................................7

3.2 Intelligent (smart) textile materials ......................................................................................................9

4 Smart textile systems ......................................................................................................................... 14

4.1 Categories ........................................................................................................................................... 15

4.2 Examples of “intelligent textile systems” and their functional analysis ...................................... 16

5 Recommendations for standardization ............................................................................................ 21

5.1 General ................................................................................................................................................. 21

5.2 Verification of claimed performances .............................................................................................. 22

5.3 Innocuousness .................................................................................................................................... 22

5.4 Durability of properties ...................................................................................................................... 22

5.5 Product information............................................................................................................................ 22

5.6 Environmental aspects ...................................................................................................................... 23

5.7 Examples of possible standardization of intelligent textile materials and systems ................... 24

Annex A (informative) Regulations, standards and conformity assessment ............................................ 28

Bibliography ..................................................................................................................................................... 32

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Foreword

This document (CEN/TR 16298:2011) has been prepared by Technical Committee CEN/TC 248 “Textiles and

textile products”, the secretariat of which is held by BSI.

Attention is drawn to the possibility that some of the elements of this document may be the subject of patent

rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.

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Introduction

Terms like “smart textile” and “intelligent textile” mean different things to different people. However, there is

some common agreement that these are textiles or textile products that possess additional intrinsic and

functional properties not normally associated with traditional textiles.

Although adjectives such as "smart" or "intelligent" are mainly intended for marketing purposes, more

technically correct definitions will not prevent the use of this terminology by textile manufacturers or by the

general public. Nor will the unintended inclusion of “non-smart” products make products any less safe or fit for

purpose.

The standardization of smart textiles or smart textile products or systems is not straightforward because it

involves an overlap between the standardization of the "traditional" textile product, e.g. a fire fighter's jacket,

and the standardization of the additional intrinsic functional properties of the "smart product", whatever they

may be. This overlap can manifest itself in a number of areas that may include:

 Legislation: all textile products should comply with the requirements of the general product safety

directive, which stipulates that only safe products should be put on the European market. Certain textile

product groups, e.g. protective clothing, geotextiles or textile floor coverings, are in addition subject to

specific national and European legislation and it may even be necessary to simultaneously address the

requirements of more than one EU Directive. A "classic" fire fighter's suit should comply with the

requirements of the PPE Directive, usually supported by EN 469, whereas a "smart" fire fighter's suit with

built-in electronic features should e.g. also comply with the applicable provisions of ICT and ATEX

regulations. Conformity assessment will also need to follow the conformity assessment schemes for both

regulations.

 Expertise: the knowledge and experience of standardization for the textile properties and for the

additional properties (temperature sensing, variable thermal insulation properties) may come from

different unrelated standardization groups. To take the above example, there will need to be input from

standardization groups working in the areas of textiles, medical devices and electric or electronic devices.

 Testing: there will be a need to test the additional functional properties to specific textile test standards

and vice versa. Again, with the same example, the electronic elements might have to be assessed for

their resistance to cleaning and the textile elements may need to be tested for electrical safety.

 Unexpected and/or unintended synergies: these might result from the combination of technologies in

smart textiles and should be recognised and addressed by standardization, wherever possible. For

example, the presence of conductive fibres to incorporate a personal stereo into a smart raincoat might

increase the risk of the wearer suffering a lightning-strike in a thunderstorm. This is despite the fact that

neither rainwear nor personal stereos, when separate, need to be assessed against this risk.

The purpose of this technical report is to give advice and information on the considerations that need to be

addressed when writing standards for smart textiles, or applying existing standards to them. This information

may be of use to:
 end-users, in determining whether a product has indeed been fully assessed;

 conformity assessment bodies, as a guide towards assessing products according to the appropriate

standards;

 specification writers, as a guide to writing new specific standards for smart textiles;

 manufacturers of smart textiles, to advise them on appropriate product testing and on suitable ways to

substantiate product claims;
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 market surveillance authorities, to help in the assessment of product claims, product safety and fitness for

purpose.

The factual information in this report is available elsewhere in a more comprehensive form and each individual

item will inevitably be common knowledge to at least one group of readers. The aim of this technical report is

to guide readers through those areas, with which they are not familiar, and to direct them towards further,

more specialised reading. In accordance with CEN rules, this Technical Report will be reviewed regularly to

keep it in line with technical and market evolutions.
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1 Scope

This Technical Report provides definitions in the field of "smart" textiles and textile products as well as a

categorisation of different types of smart textiles. It describes briefly the current stage of development of these

products and their application potential and gives indications on preferential standardization needs.

2 Terms and definitions
For the purposes of this document, the following terms and definitions apply.

In literature, both the terms ‘smart’ and ‘intelligent’ are used. In this text the two terms are considered

equivalent and hence exchangeable.

NOTE European Directive 2008/121-EC provides definitions of "textile products" and "textile fibres", but these

definitions are not suitable for the purpose of this Technical Report, since they do not distinguish between "textile

products" and "textile materials".

According to the Directive "textile products" are "raw, semi-worked, worked, semi-manufactured,

manufactured, semi-made-up or made-up products which are exclusively composed of textile fibres,

regardless of the mixing or assembly process employed" or
 (a) products containing at least 80 % by weight of textile fibres;

 (b) furniture, umbrella and sunshade coverings containing at least 80 % by weight of textile components;

similarly, the textile components of multi-layer floor coverings, of mattresses and of camping goods, and

warm linings of footwear, gloves, mittens and mitts, provided such parts or linings constitute at least 80 %

by weight of the complete article;

 (c) textiles incorporated in other products and forming an integral part thereof, where their composition is

specified.
2.1
textile material

material made of textile fibres and intended to be used, as such or in conjunction with other textile or non-

textile items, for the production of textile products
2.2
functional textile material

textile material to which a specific function is added by means of material, composition, construction and/or

finishing (applying additives, etc.)
2.3
smart textile material (intelligent textile material)

functional textile material, which interacts actively with its environment, i.e. it responds or adapts to changes in

the environment

NOTE The term "smart textile" may refer to either a "smart textile material" or a "smart textile system". Only the

context, in which the term is used, will determine which one of the two is intended.

2.4
environment (surroundings)

the circumstances, objects, or conditions, which surround a textile material or textile product or the user of that

material or product
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2.5
textile system

an assemblage of textile and non-textile components integrated into a product that still retains textile

properties, e.g. a garment, a carpet or a mattress

NOTE The terms "textile system" and "textile product" may be interchangeable in many cases.

2.6
smart textile system

a textile system which exhibits an intended and exploitable response as a reaction either to changes in its

surroundings/environment or to an external signal/input
3 Functional and smart textile materials
3.1 Functional textile materials
3.1.1 General

Functional textile materials can be components of intelligent textile systems and hence functional textile

materials, which are relevant for these intelligent textile systems, will be discussed here. This is illustrated by

the following examples:
Example 1: A textile resistance heater

 Functional textile material: a conductive material forming the basis of a resistance heater in a textile

system.

 Smart textile system: a textile resistance heater as (part of) a textile system, connected to an electrical

power supply which can only be switched on and off manually or a resistance heater as part of a textile

system, connected to an electrical power supply with a regulated power output and equipped with a

temperature sensor as to maintain a constant temperature around the heater.
Example 2: Optical fibres
 Functional textile material: optical fibres used as part of a textile system

 Smart textile system: optical fibres as (part of) a textile system, connected to a light source which can

only be switched on and off manually or optical fibres as part of a textile system, connected to a light

source with a regulated power output and equipped with a sensor to adjust the illumination level to the

amount of light present due to other light sources in the surroundings of the textile system.

3.1.2 Electrically conductive textile materials

Electrically conductive textile materials conduct an electrical current or supply an electric field to a device.

Electrical conduction is the movement of electrically charged particles through an electrical conductor, called

an electric current. The charge transport may result as a response to an electric field or as a result of a

concentration gradient in carrier density, i.e. by diffusion.

A material is considered 'electrically conductive' if it has a specific conductivity (resistivity) of > 10 S/m

4 2

(<10 Ω·cm). A material is considered to have a 'metallic conductivity' if it has a specific resistivity of > 10 S/m

(<10 Ω·cm). The materials with the highest specific conductivity are metals. Some polymers and ceramics can

also have metallic conductivity, e.g. intrinsically conductive polymers (e.g. doped polyaniline) or indium tin

oxide (ITO).
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3.1.3 Thermally conductive textile materials

Thermally conductive textile materials conduct heat. The transfer of thermal energy in a substance is due to a

temperature gradient, i.e. from a region of higher temperature to a region of lower temperature, acting to

equalize temperature differences.

Metals have thermal conductivities above approximately 20 W/(m·K) and are considered to be very good

thermal conductors. Their thermal conductivity increases with their electrical conductivity. There are also non-

metallic elements and compounds that are (very) good thermal conductors (e.g. carbon and boron nitride).

Applications in intelligent textile systems can be as a heat sink, e.g. for cooling electronic components.

3.1.4 Thermally radiative (emissive) textile materials

Thermally radiative (emissive) textile materials radiate heat, i.e. they emit electromagnetic radiation in the

infra-red range of 750 nm to 100 µm from their surface due to their temperature.

Thermal radiation (emission) can be utilized in the form of a resistance heater, where the resistance of a

conductor is used to heat the conductor to a sufficiently high temperature to generate heat radiation or as a

heat exchanger, e.g. a pipe with hot air or hot water flowing through it.

Applications in intelligent textile materials are as thermal heaters, as described in 3.1.1.

3.1.5 Optically conductive textile materials

Optically conductive textile materials transport (visible) light, i.e. electromagnetic radiation in the range of

400 nm to 750 nm.

Optical fibres from glass or plastic keep the light in their core by total internal reflection, i.e. the fibre acts as a

waveguide. Optical fibres are widely used in fibre-optic communications, which permits transmission over

longer distances and at higher bandwidths (data rates) than other forms of communications. Fibres are used

instead of metal wires because signals travel along them with less loss, and they are also immune to

electromagnetic interference.

Fibres are also used for illumination, and are wrapped in bundles so they can be used to carry images, thus

allowing viewing in tight spaces. Specially designed fibres are used for a variety of other applications,

including sensors and fibre lasers.
3.1.6 Fluorescent textile materials

Fluorescence is the molecular absorption of a photon, followed almost instantaneously by the emission of a

less energetic photon. As the emitted photon is of lower energy than the absorbed photon, the emitted light

will be of longer wavelength than the absorbed light, which allows e.g. to turn UV radiation into visible light.

Fluorescence is used in high visibility clothing for safety purposes. Fluorescent textile materials are available

in a variety of colours from red to blue-violet. A variety of organic and inorganic materials show fluorescence.

3.1.7 Phosphorescent textile materials

Phosphorescence is the molecular absorption of a photon, resulting in the formation of an excited state,

followed by the emission of a less energetic photon. Since the emitted photon is of lower energy than the

absorbed photon the emitted light will be of longer wavelength. The lifetime of the excited state in

phosphorescent materials can be very long, in the order of hours. This means that once activated,

phosphorescent materials will continue to emit light for hours without any external power supply. This makes

them suitable for emergency lighting in the case of power interruptions or for watches, toys, apparel, giving a

'glow in the dark' effect.
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Examples of phosphorescent materials are e.g. doped (mixed) sulphides (ZnS, (Cd, Zn)S, (Ca, Sr)S) or doped

(mixed) oxides (SrAl O ) but can also be organic molecules.
2 4
3.1.8 Textile materials releasing substances

These textile materials release substances at a molecular level under the influence of an external stimulus.

The substances used for this purpose are pharmaceuticals, cosmetics, fragrances, etc. They are bonded to

the textile structure by micro-encapsulation or by surface bonding.

The micro-encapsulation technique makes use of small capsules, in which the substance to be released is

enclosed. When the shell of these capsules is pierced due to an external stimulus, the substance is released.

The different stimuli that can cause piercing of the shell include mechanical force, heat, pH and contact with

water.

The surface bonding technique makes use of substances (loosely) bonded to the surface of the textile

material and released during the use of this material. The nature of the bonding and the surroundings of the

material will determine the release rate.
3.2 Intelligent (smart) textile materials
3.2.1 General

In this subclause, different intelligent (smart) textile materials will be described. Some of the textile materials

may already be composite systems. The described textile materials may be used on their own or in

combination with other (non)smart textile materials or used in textile systems. The latter is described in

clause 4.

NOTE Some of the smart functionalities may also be achieved by non-textile materials. Therefore, we will be referring

to textile materials to clearly make the distinction.
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Table 1 provides an overview of the most common stimulus-response pairs and the corresponding effect

materials or structures can exhibit.
Table 1 — Overview of stimulus-response effects (adapted from [1])
Stimulus Response
Optical Mechanical Chemical Electrical Thermal
Optical
Photochromism Photovoltaic/
photoelectric
effect
Mechanical Piezochromic Dilatant, Controlled Piezo-electricity Friction
Thixotropic, release
Auxetic
Chemical Chemiluminescence, Shape memory, Controlled Exo/endotherm
Solvatochromism, Super-absorbing release reactions
Halochromisms polymers,
Sol/hydrogel
Joule/coulombic
Electrical Electrochromism, Inverse piezo- Electrolysis
heating
Electroluminescence, electricity,
Peltier effect
Electro-optic electrostriction
Electro-osmosis
shape memory
Thermal Thermochromism, Shape memory Seebeck effect, Phase change
Thermo-opacity Pyroelectric
Shape memory
Magnetic
magnetrostriction
3.2.2 Chromic textile material

Chromic materials is the general term referring to materials whose absorption, transmission and/or reflection

of light changes due to an external stimulus. The result is a different colour impression.

Chromic materials can be classified depending on the external induction stimulus, e.g. light (photochromic),

heat (thermochromic), pressure (piezochromic), enzymes (biochromic). It goes beyond the scope of this report

to list all possible chromic effects or to discuss them in detail.

One commercial application of a thermochromic textile material is baby clothing which shows a change in

colour when the baby has developed a fever. Other applications envisioned for safety clothing are the use of

chromic textile materials for indicating exposure to chemicals or radiation.
3.2.3 Phase change textile material

A phase change material (PCM) is a substance which is capable of storing and releasing large amounts of

energy in the form of latent heat, at a specified temperature range (range of phase transformation) during

which the material changes phase or state (from solid to liquid or from liquid to solid). This energy (heat) is

absorbed or released when the material changes from solid to liquid (or the other way around), thus buffering

any external temperature change by evoking a phase transition in the material.

Classic PCMs are water, hydrated salt complexes and saturated hydrocarbons (where the length of the chain

will determine the melting point). Depending on the nature of the phase change, e.g. when formation of a

liquid phase is involved, micro-encapsulation will be required. The choice of material or composite will depend

on the temperature to be buffered.
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The most common method today to produce phase change textile materials is by coating or impregnating

fibres or fabrics with a polymeric binder containing micro-encapsulated PCMs. Alternatively, micro-

encapsulated PCMs may be incorporated into fibres during the fibre spinning or filling of hollow fibres. They

may also be laminated as a PCM containing polymeric film onto a textile structure.

Space suits and gloves were the first application of phase change materials (PCM), but nowadays PCMs are

also used for consumer products to improve the thermal comfort of active-wear garments and clothing textiles.

During a sports activity, the thermal stress is mainly due the disequilibrium between the heat produced by the

human body during an effort, and the heat released into the environment. When PCMs are encapsulated on

underwear, during the same activity a larger amount of the human heat will be released to the environment.

3.2.4 Shape change (shape memory) textile materials

These materials change in shape, size or internal structure upon an external stimulus, e.g. temperature, UV

light, moisture, magnetic field, pH value. The shape change can have a one-way or a two-way effect.

A one-way material has a preformed structure, which returns in a non-reversible way to its original, not-

preformed state after receiving an external stimulus.

A two-way material or composite can be cycled between two different preformed states by receiving opposing

external stimuli, e.g. a higher and lower temperature.
Shape memory materials can be:

 polymers with a combination of permanent physical or chemical cross-links, integrated into a mobile

matrix, which is able to store mechanical deformation energy until recovery is activated by an external

stimulus;

 metal alloys switching between two different crystal structures upon a thermal impulse, e.g. Nitinol, or

 composites of shape-memory-materials and materials providing an elastically restoring force in one unit

(e.g. artificial muscles).

Shape memory materials can be implemented in textile systems in the form of yarns, i.e. in the bulk of the

textile structure or as a coating on a fabric, e.g. creating a membrane. Applications can be textile systems

adjusting their shape, e.g. a garments reducing its length when exposed to heat; or a membrane adjusting its

porosity, e.g. to adjust the water vapour transmission rate.
3.2.5 Super-absorbing polymers and gels

Super-absorbing polymers and gels absorb and retain extremely large amounts of liquid relative to their own

mass resulting in strong swelling and gel formation. Water absorbing polymers (hydrogels) absorb aqueous

solutions through hydrogen bonding with water molecules. The ability to absorb water depends on the

presence of ions in the water, being 500 times its weight (30 to 60 times its volume) for distilled or deionised

water, but only 50 times its weight for a 0.9 % saline solution.

The total absorbency and swelling capacity are controlled by the type and degree of cross-linking in the

polymer. A low-density cross-linked polymer has a higher absorbent capacity and a softer and more cohesive

gel is formed. High cross-link density polymers exhibit lower absorption capacity but the gel strength is firmer,

maintaining its shape under low pressure.

Examples of the use of super-absorbing polymers are hygiene products, blockage of water penetration in

underground power communication cables, horticultural water retention agents, spill and waste control,

artificial snow for motion picture and stage production and filtration.
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3.2.6 Auxetic textile materials

Auxetic materials or composites harden and laterally expand upon elongation. This phenomenon is caused by

the macro-structure or micro-structure of the material and not by its chemical composition. Such materials

have a so-called negative Poisson ratio.

Some auxetic textile materials contain on a micro-scale both temporary, relatively weak bonds (e.g. hydrogen

bonds), which can be broken and restored (slipping from one to the other) under a low shear force and stable

bonds, which, under a high shear force, will counter the full load of the force, resulting in a 'stiff' behaviour.

Other auxetic textile materials are based on the use of materials with diverging properties, e.g. a textile yarn

comprising a thicker, elastic cord entwined with a thinner, stiffer cord. When tensioned the system will change

to the thin, stiff cord being entwined by the thicker, elastic cord and the total diameter will be increased as

compared to the relaxed state.

Auxetic textile materials are intended for improved energy absorption and fracture resistance. Examples of

auxetic textile applications are blast resistance, window covering, military tents, and hurricane defence.

Examples of auxetic foam materials are found in sound and shock absorption, medical engineering, filtration

of biological fluids and process engineering.
3.2.7 Dilating and shear-thickening textile material

These materials show an increase in viscosity with increasing shear rate, i.e. they will become hard upon

impact and remain soft under low force movement.

A dilatant effect occurs when closely packed particles are combined with enough liquid to fill the gaps between

them. At low flow velocities, the liquid acts as a lubricant, and the dilatant flows easily. At higher flow

velocities, the liquid is unable to fill the gaps created between particles, friction

...

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