prEN ISO 7231

Polymeric materials, cellular, flexible - Determination of air flow value at constant pressure-drop (ISO/DIS 7231:2022)

Weich-elastische Polymerschaumstoffe – Bestimmung der Luftdurchlässigkeit bei konstantem Differenzdruck(ISO/DIS 7231:2022)

Matériaux polymères alvéolaires souples - Détermination de l'indice d'écoulement d'air à chute de pression constante (ISO/DIS 7231:2022)

Polimerni materiali - Penjeni polimeri - Mehke pene - Določanje vrednosti zračnega pretoka pri konstantni razliki tlakov (ISO/DIS 7231:2022)

General Information

• Status: Not Published
• Publication Date: 15-Jul-2024
• ICS: 83.100 - Cellular materials
• Technical Committee: CEN/TC 249 - Plastics
• Drafting Committee: CEN/TC 249 - Plastics
• Current Stage: 4599 - Dispatch of FV draft to CMC - Finalization for Vote
• Start Date: 15-May-2023
• Completion Date: 31-Mar-2023
• Ref Project: oSIST prEN ISO 7231:2022 - Polymeric materials, cellular, flexible - Determination of air flow value at constant pressure-drop (ISO/DIS 7231:2022)

Relations

• Revises: EN ISO 7231:2010 - Polymeric materials, cellular, flexible - Determination of air flow value at constant pressure-drop (ISO 7231:2010)
• Effective Date: 18-Jan-2023

Standards Content (Sample)

SLOVENSKI STANDARD
oSIST prEN ISO 7231:2022
01-september-2022

Polimerni materiali - Penjeni polimeri - Mehke pene - Določanje vrednosti zračnega

pretoka pri konstantni razliki tlakov (ISO/DIS 7231:2022)

Polymeric materials, cellular, flexible - Determination of air flow value at constant

pressure-drop (ISO/DIS 7231:2022)
Weich-elastische Polymerschaumstoffe – Bestimmung der Luftdurchlässigkeit bei
konstantem Differenzdruck(ISO/DIS 7231:2022)

Matériaux polymères alvéolaires souples - Détermination de l'indice d'écoulement d'air à

chute de pression constante (ISO/DIS 7231:2022)
Ta slovenski standard je istoveten z: prEN ISO 7231
ICS:
83.100 Penjeni polimeri Cellular materials
oSIST prEN ISO 7231:2022 en,fr,de

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

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oSIST prEN ISO 7231:2022
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oSIST prEN ISO 7231:2022
DRAFT INTERNATIONAL STANDARD
ISO/DIS 7231
ISO/TC 45/SC 4 Secretariat: DSM
Voting begins on: Voting terminates on:
2022-06-21 2022-09-13
Polymeric materials, cellular, flexible — Determination of
air flow value at constant pressure-drop

Matériaux polymères alvéolaires souples — Détermination de l'indice d'écoulement d'air à chute de

pression constante
ICS: 83.100
This document is circulated as received from the committee secretariat.
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENT AND APPROVAL. IT IS
ISO/CEN PARALLEL PROCESSING
THEREFORE SUBJECT TO CHANGE AND MAY
NOT BE REFERRED TO AS AN INTERNATIONAL
STANDARD UNTIL PUBLISHED AS SUCH.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL,
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
STANDARDS MAY ON OCCASION HAVE TO
BE CONSIDERED IN THE LIGHT OF THEIR
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
Reference number
NATIONAL REGULATIONS.
ISO/DIS 7231:2022(E)
RECIPIENTS OF THIS DRAFT ARE INVITED
TO SUBMIT, WITH THEIR COMMENTS,
NOTIFICATION OF ANY RELEVANT PATENT
RIGHTS OF WHICH THEY ARE AWARE AND TO
PROVIDE SUPPORTING DOCUMENTATION. © ISO 2022
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oSIST prEN ISO 7231:2022
ISO/DIS 7231:2022(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2022

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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Published in Switzerland
© ISO 2022 – All rights reserved
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oSIST prEN ISO 7231:2022
ISO/DIS 7231:2022(E)
Contents Page

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

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

2 Normative references ..................................................................................................................................................................................... 1

3 Terms and definitions .................................................................................................................................................................................... 1

4 Principle ........................................................................................................................................................................................................................ 1

5 Method A ....................................................................................................................................................................................................................... 2

5.1 Apparatus .................................................................................................................................................................................................... 2

5.1.1 General ........................................................................................................................................................................................ 2

5.1.2 Flow meters ............................................................................................................................................................................ 2

5.1.3 Manometer ............................................................................................................................................................................... 2

5.1.4 Air supply or suction equipment .......................................................................................................................... 2

5.1.5 Test piece mounting ........................................................................................................................................... .............. 2

5.1.6 Vacuum chamber operated at below atmosphere pressure ........................................................ 2

5.2 Test pieces ................................................................................................................................................................................................... 3

5.3 Test conditions ........................................................................................................................................................................................ 3

5.4 Procedure .................................................................................................................................................................................................... 3

5.5 Test report .................................................................................................................................................................................................. 3

6 Method B ....................................................................................................................................................................................................................... 5

6.1 Method B1 with manual measurement ............................................................................................................................ 5

6.1.1 Apparatus ................................................................................................................................................................................. 5

6.1.2 Test pieces ................................................................................................................................................................................ 6

6.1.3 Test conditions ..................................................................................................................................................................... 6

6.1.4 Procedure ................................................................................................................................................................................. 6

6.1.5 Precision .................................................................................................................................................................................... 9

6.1.6 Test report ................................................................................................................................................................................ 9

6.2 Method B2 with automatic measurement ...................................................................................................................... 9

6.2.1 Apparatus ................................................................................................................................................................................. 9

6.2.2 Test pieces ............................................................................................................................................................................. 11

6.2.3 Test conditions .................................................................................................................................................................. 11

6.2.4 Procedure .............................................................................................................................................................................. 12

6.2.5 Test report .............................................................................................................................................................................12

Annex A (informative) Precision of Method B1 .....................................................................................................................................13

Bibliography .............................................................................................................................................................................................................................15

iii
© ISO 2022 – All rights reserved
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oSIST prEN ISO 7231:2022
ISO/DIS 7231:2022(E)
Foreword

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

electrotechnical standardization.

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

on the ISO list of patent declarations received (see www.iso.org/patents).

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

constitute an endorsement.

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/iso/foreword.html.

This document was prepared by Technical Committee ISO/TC45, Rubber and rubber products,

Subcommittee SC 4, Products (other than hoses).

This third edition cancels and replaces the second edition (ISO 7231:2010), which has been technically

revised.
The main changes compared to the previous edition are as follows:
— Annex A has been included into the body text as method B2.

— Subclause 6.5, the precision of method B1 has been moved to Annex A as informative.

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.
© ISO 2022 – All rights reserved
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oSIST prEN ISO 7231:2022
DRAFT INTERNATIONAL STANDARD ISO/DIS 7231:2022(E)
Polymeric materials, cellular, flexible — Determination of
air flow value at constant pressure-drop

WARNING — Persons using this document should be familiar with normal laboratory practice.

This document does not purport to address all of the safety problems, if any, associated with its

use. It is the responsibility of the user to establish appropriate safety and health practices and to

ensure compliance with any national regulatory conditions.
1 Scope

This document specifies two methods for determining the air flow value of flexible cellular polymeric

materials:
— method A, for conventional types of flexible cellular polymeric material;

— method B, for all types of flexible cellular polymeric material, but especially for materials with a low

permeability to air.
For method B two methods are specified in this document:
— Method B1: with manual measurement
— Method B2: with automatic measurement

NOTE 1 Air flow values can be used to give an indication of the effects of formulation and production variables

on the cellular structure.

NOTE 2 In this document, the expression “conventional type of flexible cellular polymeric material” means

types which are unsuitable for sealing purposes.
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 terminological 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
air flow value

volume flow rate required to maintain a constant pressure differential across a flexible foam test piece.

4 Principle

A specified constant air pressure differential is created across a standard flexible foam specimen. The

rate of flow of air required to maintain this pressure differential is measured as the air flow value.

© ISO 2022 – All rights reserved
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oSIST prEN ISO 7231:2022
ISO/DIS 7231:2022(E)
5 Method A
5.1 Apparatus
5.1.1 General

Diagrams of suitable apparatus are shown in Figure 1 (using an air pressure below atmospheric) and

Figure 2 (using an air pressure above atmospheric). The essential parts are described in 5.1.2 to 5.1.5.

5.1.2 Flow meters

Low-pressure-drop flow meters with an accuracy of up to ±2 % are required for air flow measurements.

The actual air flow shall be adjusted by a combination of valve restriction, as shown in Figures 1 and 2,

and blower or vacuum pump speed, so that the required pressure difference across the specimen [see

5.4 c)] is maintained constant.

Air flow meters with at least 250 mm scales are recommended. Flow-meters measuring in the range

3 3
0 dm /s to 10 dm /s will cover a wide variety of cellular polymeric materials.
5.1.3 Manometer

A manometer graduated in the 0 Pa to 250 Pa range and with an accuracy of ±2 % is required. Traps to

prevent manometer fluid being drawn into the test chamber by accidental pressure changes shall be

provided. A plunger in the fluid reservoir is used to set the zero point after levelling the manometer.

The use of an inclined manometer with 2 Pa graduations is recommended. A level mounted on the

manometer should be used to ensure that the proper degree of inclination from the horizontal is

maintained.
5.1.4 Air supply or suction equipment

The air supply or suction may be such that positive or negative pressure differences from atmospheric

pressure are obtained across the test piece, using compressed air, an exhaust blower or a vacuum pump,

etc.

NOTE A particular apparatus can be constructed to use only positive or negative pressure.

5.1.5 Test piece mounting
A chamber of nominal dimensions 140 mm diameter × 150 mm depth (see Figure 1) or

75 mm diameter × 1 000 mm length (see Figure 2), incorporating a test piece mounting and

fittings for the manometer and exhaust, shall be provided. The test piece cavity shall be

(50 ± 0,05) mm × (50 ± 0,05) mm × (25 ± 0,05) mm.

The test piece shall be supported by suitable means, for example by the use of vanes, wires or a

perforated support. The support shall provide a minimum open proportion of 70 % of the overall area,

evenly distributed over its area (see Figures 1 and 2 for the positioning of the supports). Manometer

and exhaust fittings shall be as shown in Figures 1 and 2.
5.1.6 Vacuum chamber operated at below atmosphere pressure

The apparatus, shown in Figure 1, shall be checked for leaks in the following manner:

a) Seal the test piece mounting cavity with masking tape.

b) With all the flow-meter valves closed, turn the air supply to approximately one-third of the

maximum setting and observe any movement of the manometer. The manometer reading shall not

exceed 1 Pa after 30 s.
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oSIST prEN ISO 7231:2022
ISO/DIS 7231:2022(E)

c) Open the valve on the lowest-range flow-meter very slightly. The flow shall be essentially zero, as

shown by a movement of less than 3 mm of the flow-meter float from its static position.

5.2 Test pieces

The test pieces shall normally be in the form of a right parallelepiped of dimensions

(51,0 ± 0,3) mm × (51,0 ± 0,3) mm × (25,0 ± 0,3) mm. If test pieces of a different thickness are used, the

thickness shall be stated in the test report. Any test pieces with le
...