ISO/PRF TR 20342-7

TECHNICAL ISO/TR
REPORT 20342-7
First edition
Assistive products for tissue integrity
when lying down —
Part 7:
Foam properties, characteristics and
performance
PROOF/ÉPREUVE
Reference number
ISO/TR 20342-7:2021(E)
ISO 2021
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ISO/TR 20342-7:2021(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2021

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Foreword ........................................................................................................................................................................................................................................iv

Introduction ..................................................................................................................................................................................................................................v

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 2

3 Terms and definitions ..................................................................................................................................................................................... 2

4 Test samples and foam properties ..................................................................................................................................................... 4

4.1 General ........................................................................................................................................................................................................... 4

4.2 Test samples .............................................................................................................................................................................................. 4

4.3 Presale literature ................................................................................................................................................................................... 5

4.4 Composite APTIs ................................................................................................................................................................................... 5

4.5 Foam density and hardness ......................................................................................................................................................... 5

4.6 Aging effects .............................................................................................................................................................................................. 5

5 Test methods ............................................................................................................................................................................................................. 6

5.1 General ........................................................................................................................................................................................................... 6

5.2 Determination of foam type ......................................................................................................................................................... 6

5.2.1 Resilience (ball rebound) ......................................................................................................................................... 6

5.2.2 Hysteresis ............................................................................................................................................................................... 6

5.2.3 Support/SAG factor ....................................................................................................................................................... 6

5.3 Characterization of foam durability ...................................................................................................................................... 6

5.3.1 Density (core or apparent)...................................................................................................................................... 6

5.3.2 Tensile strength and elongation ......................................................................................................................... 7

5.3.3 Tear strength ....................................................................................................................................................................... 7

5.3.4 Compression set (wet and/or dry) .................................................................................................................. 7

5.4 Characterization of foam hardness ........................................................................................................................................ 7

5.4.1 General...................................................................................................................................................................................... 7

5.4.2 Indentation hardness ................................................................................................................................................... 8

5.4.3 Compression hardness ............................................................................................................................................... 8

5.5 Characterization of other properties ................................................................................................................................... 8

5.5.1 Dynamic Fatigue Test (Pounding) ..................................................................................................................... 8

5.5.2 Dynamic Fatigue Test (Roller) .............................................................................................................................. 8

5.5.3 Air flow/permeability ................................................................................................................................................. 8

5.5.4 Flammability ....................................................................................................................................................................... 8

5.5.5 Microbial resistance ...................................................................................................................................................... 9

5.5.6 Restricted substances .................................................................................................................................................. 9

Annex A (informative) Cross-reference guide between related ISO, ASTM, and JIS standards .............10

Bibliography .............................................................................................................................................................................................................................11

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 has been established has the right to be represented on that committee. International

organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.

ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of

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 documents 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).

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

patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of

any patent rights identified during the development of the document will be in the Introduction and/or

Any trade name used in this document is information given for the convenience of users and does not

For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO's adherence to the

World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www .iso .org/

This document was prepared by Technical Committee ISO/TC 173 Assistive products, in collaboration

with the European Committee for Standardization (CEN) Technical Committee CEN/TC 293, Assistive

products and accessibility, in accordance with the Agreement on technical cooperation between ISO and

Any feedback or questions on this document should be directed to the user’s national standards body. A

Although the phrase ‘high specification foam mattress’ has been common in the industry for several

The first ‘high specification foam mattresses’ were introduced around the 1990s. These incorporated

multiple construct layers of different foams, some of which might be castellated and/or shaped, and

then enveloped in stretch covers to provide improved pressure reducing properties when compared

with the then, ‘standard hospital mattress’, which was essentially a single rectangular block of foam

protected by a non-stretch cover. Over time these more advanced, complicated multi-layer constructs

have themselves now become the norm, completely replacing the old product in most modern hospitals.

Continued use of the ‘high specification’ terminology creates the risk of confusion and allows

manufacturers to lay claim to providing a ‘high specification foam mattress’ without an agreed

benchmark against which to justify this claim. The continued use of this phrase also takes the focus

away from the principles of holistic care and the correct risk assessment leading hopefully to the

selection of the mattress that will most likely deliver the desired outcome depending on the needs of

Looking at the different clinical requirements and physical properties for foam mattresses, different

properties and their values come into play depending on the identified needs. A single property that

might be considered ‘high’ specification or highly desirable in relation to one patient or healthcare

environment could well be deemed ‘low’ or somewhat unimportant when considered against the needs

of the next patient in a different environment. Ultimately, it is the performance of the mattress as a

whole, within its environment, rather than any individual component part of it, that is important.

Understanding the characteristics of foam can help inform and potentially aid in the choice when

several products are available. However, it is the performance of the complete product, based on the

Without knowing the current (and often evolving) clinical needs of every particular user, it is not

possible to define clearly a nominal or minimal/maximal performance specification that needs to be

Additional safety standards, such as fire resistance at a component and/or final product level, exist

in relation to the foam product addressed in this document. The minimum level of resistance legally

required potentially differs depending on the application environment, for example domestic versus

hospital use. The flammability requirements and test methods used currently differ depending on the

The manufacturer is required to explain and corroborate any claims made concerning the important

features of their product and how these features assure the clinical efficiency of their product over its

Based on this information and/or local, national or international requirements, it remains, however,

the responsibility of the user to determine if the foam proposed provides merely adequate behaviour or

Not all of the proposed tests need to be carried out to give an indication of a foam's performance and

some of the proposed tests will not be considered relevant for some types of foam.

These test methods can be used to identify differing performance characteristics between products

It is emphasized that the test methods specified in this document do not necessarily simulate conditions

of use in practice. The use of resulting data is therefore restricted to a broad comparative assessment

It is recommended that no single result be taken in isolation. The clinical efficiency of the final product

will also be the result of many different contributory factors, a large number of which will not be related

The type of cover (fabric or other) used on the APTI can have a significant effect on overall clinical

performance of the final product. An incorrectly fitted cover, or changing the cover to a product other

than that specified by the manufacturer, will possibly affect product safety, performance and durability.

Continued use of a damaged cover can result in penetration of liquids into the foam, not only potentially

The type of bedframe, or support, onto which the APTI is placed potentially affects the performance of

the final product. Overall product dimensions need to be taken into account not only to ensure that the

APTI can function correctly, but also to ensure that no entrapment hazards are created between the

This document lists the terminology and common test methods used by manufacturers and laboratories

to quantify the performance of a foam material. It also and gives information to users or buyers of these

products to make an educated assessment of the relevance of the physical characteristics between

— polyurethane foams – typically polyether (polyether polyurethane foam) or polyester based

(polyester polyurethane foam) – produced by either slabstock (slabstock foam) or moulded foam

NOTE The test methods presented in this document do not necessarily simulate conditions of use in practice.

The use of resulting data is therefore restricted to a broad comparative assessment between different foam

This document addresses only the characterization and performance of foam materials used in APTIs. It

does not address the design, construction method or other factors relating to the final clinical efficiency

Test methods for characterizing the physical properties of any coverings, or the effects of any coverings

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 20342-1, Assistive products for tissue integrity when lying down — Part 1: General requirements

For the purposes of this document, the terms and definitions given in ISO 20342-1 and the following

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

surface intended to protect body tissue, designed to interface with the body when lying down or in

insufficient support provided by an assistive product for tissue integrity (3.1) for the mass of patient

concerned, at the place where the assistive product for tissue integrity is no longer capable of

Note 1 to entry: Localized pressure risks are now placed onto the patient by the bed frame or support surface

Note 1 to entry: The preparation of this test part renders an assistive product for tissue integrity (3.1) unsuitable

action where foamed liquid latex is poured into a mould before vulcanization (3.10)

Note 1 to entry: Continuous production [see slabstock foam (3.11.6)] using the Dunlop process is also possible.

chemical reaction in which the interaction of a compound with water results in the gradual

Note 1 to entry: An assistive product for tissue integrity (3.1) is not significantly altered by the test and is deemed

action where foamed liquid latex is poured into a mould then placed under vacuum before vulcanization

chemical cross linking of rubber-based polymers to increase product rigidity and durability

flexible cellular material in which the cells are all or partly intercommunicating

foam (3.11) characterized by higher elasticity, measured by ball rebound or comfort factor (SAG factor),

Note 1 to entry: Special high resilience polyols are used frequently in combination with methylene diphenyl di-

Note 2 to entry: The higher elasticity is attributed to a more irregular cell structure than that present in standard

flexible cellular material made from natural or synthetic latex (3.11.2.2), in which the cells are all or