EN 27326:1993

SLOVENSKI STANDARD
01-december-2000
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,62
Rubber and plastics hoses - Assessment of ozone resistance under static conditions
(ISO 7326:1991)
Gummi- und Kunststoffschläuche - Bestimmung der Ozonbeständigkeit unter statischen
Bedingungen (ISO 7326:1991)
Tuyaux en caoutchouc et en plastique - Evaluation de la résistance a l'ozone dans des
conditions statiques (ISO 7326:1991)
Ta slovenski standard je istoveten z: EN 27326:1993
ICS:
23.040.70
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

ISO
INTERNATIONAL
STANDARD
Second edition
199 1-02-15
Rubber and plastics hoses - Assessment of
ozone resistance under static conditions
Tuyaux en caoutchouc et en plastique - Evaluation de la rkistance &
I’ozone dans des conditions statiques
Reference number
ISO 7326:1991(E)
ISO 7326:1991(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. Esch 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, govern-
mental 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.
Draft International Standards adopted by the technical committees are
circulated to the member bodies for voting. Publication as an Inter-
national Standard requires approval by at least 75 % of the member
bodies casting a vote.
International Standard ISO 7326 was prepared by Technical Committee
ISO/TC 45, Rubber and rubber products.
This second edition cancels and replaces the first edition
(ISO 7326:1984), clause 1 of which has been technically revised.
0 ISO 1991
All rights reserved. No part of this publication may be reproduced or utiiized in any form
or by any means, electronie or mechanical, including photocopying and microfilm, without
permission in writing from the publisher.
International Organization for Standardkation
Case Postale 56 l CH-121 1 Geneve 20 l Switzeriand
Printed in Switzeriand
ii
ISO 7326:1991(E)
Introduction
The methods described in this international Standard provide a means
of assessing the resistance of hoses to the deleterious effects of at-
mospheric ozone under static conditions.
. . .
Ill
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ISO 7326:1991(E)
INTERNATIONAL STANDARD
Rubber and plastics hoses - Assessment of ozone resistance
under static conditions
agreements based on this International Standard
1 Scope
are encouraged to investigate the possibility of ap-
plying the most recent editions of the Standards in-
This international Standard specifies three methods
dicated below. Members of IEC and ISO maintain
for determining the resistance of the outer covers
registers of currently valid International Standards.
of hoses to ozone:
Standard temperatures, hu-
ISO 471:1983, Rubber -
method 1 - for bore sizes up to and including
midities and times for the conditioning and testing
25 mm carried out on the hose itself;
of test pieces.
method 2 - for bore sizes greater than 25 mm
ISO 143%1:1989, Rubber, vulcanized or thermoplas-
carried out on a test piece from the hose Wall;
tic - Resistance to ozone cracking - Part 1: Static
strain test.
method 3 - for bore sizes greater than 25 mm
carried out on a test piece from the cover.
ISO 1826: 1981, Rubber, vulcanized - Time-interval
Method 1 or 2 shall normally be used. Method 3 between vulcanization and testing - Specification.
shall be used only if it is not possible to carry out the
test in accordance with method 2. ISO 466%1:1986, Rubber, vulcanized - Preparation
of samples and test pieces - Part 1: Physical tests.
The results of tests carried out in accordance with
method 1 may not be comparable with the results
obtained when tests are carried out in accordance
3 Apparatus
with methods 2 and 3, notwithstanding that the cover
compounds of the hoses under test are identical in
composition and are cured to the Same degree. The
3.1 Ozone cabinet, with apparatus for generating
test method to be used shall be as specified in the
ozone and monitoring and controlling the ozone
product Standard.
concentration, as described in ISO 1431-1.
NOTE 1 For hoses with built-in fittings from which it is
not possible to take test pieces, the ozone resistance may
3.2 Test piece holder, as shown in figure 1 (for
be assessed on slabs in accordance with ISO 1431-1, us-
method 1).
ing test sheets of the appropriate polymeric compound
vulcanized to the same degree.
3.3 Test piece holder, as shown in figure 2 (for
method 2), made, for example, of wood coated with
paint or aluminium.
3.4 Jig, for elongation of test pieces (for method 3).
2 Normative references
Details given in ISO 1431-1:1989, sub-clause 5.6,
The following Standards conta
...