Polymeric materials, cellular, flexible - Determination of air flow value at constant pressure-drop (ISO 7231:2010)

ISO 7231:2010 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.

Weich-elastische Polymerschaumstoffe - Bestimmung der Luftdurchlässigkeit bei konstantem Druck (ISO/FDIS 7231:2010)

weich-elastischen Polymerschaumstoffen fest.
 Verfahren A, für die herkömmlichen Typen weich-elastischer Polymerschaumstoffe;
 Verfahren B, für alle Arten weich-elastischer Polymerschaumstoffe, jedoch insbesondere für Materialien
mit geringer Luftdurchlässigkeit.
ANMERKUNG 1 Luftdurchlässigkeitswerte können als Anhaltspunkt für den Einfluss von Rezeptur und Herstellungsvariablen
auf die Zellenstruktur verwendet werden.
ANMERKUNG 2 In dieser Internationalen Norm steht der Ausdruck „herkömmlicher Typ weich-elastischer Polymerschaumstoffe“
für Typen, die nicht zum Abdichten geeignet sind.

Matériaux polymères alvéolaires souples - Détermination de l'indice d'écoulement d'air à chute de pression constant (ISO 7231:2010)

L'ISO 7231:2010 spécifie deux méthodes de détermination de l'indice d'écoulement d'air des matériaux polymères alvéolaires souples:
méthode A, pour les matériaux polymères alvéolaires souples classiques;
méthode B, pour tous types de matériaux polymères alvéolaires souples, mais essentiellement pour les matériaux ayant une faible perméabilité à l'air.

Polimerni materiali - Penjeni polimeri - Mehke pene - Določanje vrednosti zračnega pretoka pri konstantni razliki tlakov (ISO 7231:2010)

Ta mednarodni standard določa dve metodi za določanje vrednosti zračnega pretoka mehkih penjenih polimernih materialov: - metoda A za konvencionalne vrste mehkih penjenih polimernih materialov; - metoda B za vse vrste mehkih penjenih polimernih materialov, predvsem pa za materiale z nizko prepustnostjo zraka.

General Information

Status
Published
Publication Date
30-Jun-2010
Technical Committee
Current Stage
6060 - Definitive text made available (DAV) - Publishing
Due Date
01-Jul-2010
Completion Date
01-Jul-2010

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Standards Content (sample)

SLOVENSKI STANDARD
SIST EN ISO 7231:2010
01-september-2010
1DGRPHãþD
SIST EN ISO 7231:1999

3ROLPHUQLPDWHULDOL3HQMHQLSROLPHUL0HKNHSHQH'RORþDQMHYUHGQRVWL]UDþQHJD

SUHWRNDSULNRQVWDQWQLUD]OLNLWODNRY ,62

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

pressure-drop (ISO 7231:2010)
Weich-elastische Polymerschaumstoffe - Bestimmung der Luftdurchlässigkeit bei
konstantem Druck (ISO 7231:2010)

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

chute de pression constante (ISO 7231:2010)
Ta slovenski standard je istoveten z: EN ISO 7231:2010
ICS:
83.100 Penjeni polimeri Cellular materials
SIST EN ISO 7231:2010 en,fr

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

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SIST EN ISO 7231:2010
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SIST EN ISO 7231:2010
EUROPEAN STANDARD
EN ISO 7231
NORME EUROPÉENNE
EUROPÄISCHE NORM
July 2010
ICS 83.100 Supersedes EN ISO 7231:1997
English Version
Polymeric materials, cellular, flexible - Determination of air flow
value at constant pressure-drop (ISO 7231:2010)

Matériaux polymères alvéolaires souples - Détermination Weich-elastische Polymerschaumstoffe - Bestimmung der

de l'indice d'écoulement d'air à chute de pression constant Luftdurchlässigkeit bei konstantem Druck (ISO 7231:2010)

(ISO 7231:2010)
This European Standard was approved by CEN on 2 June 2010.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European

Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national

standards may be obtained on application to the CEN Management Centre or to any CEN member.

This European Standard exists in three official versions (English, French, German). A version in any other language made by translation

under the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as the

official versions.

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

© 2010 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 7231:2010: E

worldwide for CEN national Members.
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SIST EN ISO 7231:2010
EN ISO 7231:2010 (E)
Contents Page

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

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SIST EN ISO 7231:2010
EN ISO 7231:2010 (E)
Foreword

This document (EN ISO 7231:2010) has been prepared by Technical Committee ISO/TC 45 “Rubber and

rubber products” in collaboration with Technical Committee CEN/TC 249 “Plastics” the secretariat of which is

held by NBN.

This European Standard shall be given the status of a national standard, either by publication of an identical

text or by endorsement, at the latest by January 2011, and conflicting national standards shall be withdrawn at

the latest by January 2011.

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.

This document supersedes EN ISO 7231:1997.

According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following

countries are bound to implement this European Standard: 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 the United Kingdom.
Endorsement notice

The text of ISO 7231:2010 has been approved by CEN as a EN ISO 7231:2010 without any modification.

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SIST EN ISO 7231:2010
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SIST EN ISO 7231:2010
INTERNATIONAL ISO
STANDARD 7231
Second edition
2010-07-01
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
Reference number
ISO 7231:2010(E)
ISO 2010
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SIST EN ISO 7231:2010
ISO 7231:2010(E)
PDF disclaimer

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COPYRIGHT PROTECTED DOCUMENT
© ISO 2010

All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,

electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or

ISO's member body in the country of the requester.
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Published in Switzerland
ii © ISO 2010 – All rights reserved
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SIST EN ISO 7231:2010
ISO 7231:2010(E)
Contents Page

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

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

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

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

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

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

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

Annex A (informative) Automatic measurements in method B......................................................................9

© ISO 2010 – All rights reserved iii
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SIST EN ISO 7231:2010
ISO 7231:2010(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.

International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.

The main task of technical committees is to prepare International Standards. Draft International Standards

adopted by the technical committees are circulated to the member bodies for voting. Publication as an

International Standard requires approval by at least 75 % of the member bodies casting a vote.

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.

ISO 7231 was prepared by Technical Committee ISO/TC 45, Rubber and rubber products, Subcommittee

SC 4, Products (other than hoses).

This second edition cancels and replaces the first edition (ISO 7231:1984), which has been technically revised.

Major modifications in this revision are:
a) the inclusion of a warning statement;

b) the inclusion of a new method (method B) particularly suitable for materials with a low permeability to air;

c) the inclusion of precision data for method B;

d) the inclusion of an example showing how a computer-controlled apparatus could be used to carry out

method B.
iv © ISO 2010 – All rights reserved
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SIST EN ISO 7231:2010
INTERNATIONAL STANDARD ISO 7231:2010(E)
Polymeric materials, cellular, flexible — Determination of air
flow value at constant pressure-drop

WARNING — Persons using this International Standard should be familiar with normal laboratory

practice. This standard 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 International Standard 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.

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 International Standard, the expression “conventional type of flexible cellular polymeric material” means

types which are unsuitable for sealing purposes.
2 Normative references

The following referenced documents are indispensable for the application 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/TR 9272, Rubber and rubber products — Determination of precision for test method standards

3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
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 the air flow value.

© ISO 2010 – All rights reserved 1
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SIST EN ISO 7231:2010
ISO 7231:2010(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 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 Test chamber operated at below atmospheric 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.

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.

2 © ISO 2010 – All rights reserved
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SIST EN ISO 7231:2010
ISO 7231:2010(E)
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 piec
...

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