EN ISO 8031:2009

SLOVENSKI STANDARD
01-februar-2010
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SIST EN ISO 8031:2000
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Rubber and plastics hoses and hose assemblies - Determination of electrical resistance
and conductivity (ISO 8031:2009)
Gummi- und Kunststoffschläuche und Schlauchleitungen - Bestimmung der elektrischen
Eigenschaften, des Widerstands und der Leitfähigkeit (ISO 8031:2009)
Tuyaux et flexibles en caoutchouc et en plastique - Détermination de la résistance et de
la conductivité électriques (ISO 8031:2009)
Ta slovenski standard je istoveten z: EN ISO 8031:2009
ICS:
23.040.70 Gumene cevi in armature Hoses and hose assemblies
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN ISO 8031
NORME EUROPÉENNE
EUROPÄISCHE NORM
October 2009
ICS 23.040.70 Supersedes EN ISO 8031:1997
English Version
Rubber and plastics hoses and hose assemblies - Determination
of electrical resistance and conductivity (ISO 8031:2009)
Tuyaux et flexibles en caoutchouc et en plastique - Gummi- und Kunststoffschläuche und Schlauchleitungen -
Détermination de la résistance et de la conductivité Bestimmung der elektrischen Eigenschaften, des
électriques (ISO 8031:2009) Widerstands und der Leitfähigkeit (ISO 8031:2009)
This European Standard was approved by CEN on 10 October 2009.

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, 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
© 2009 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 8031:2009: E
worldwide for CEN national Members.

Contents Page
Foreword .3

Foreword
This document (EN ISO 8031:2009) has been prepared by Technical Committee ISO/TC 45 "Rubber and
rubber products" in collaboration with Technical Committee CEN/TC 218 “Rubber and plastics hoses and
hose assemblies” the secretariat of which is held by BSI.
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 April 2010, and conflicting national standards shall be withdrawn at the
latest by April 2010.
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 8031:1997.
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, 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 8031:2009 has been approved by CEN as a EN ISO 8031:2009 without any modification.

INTERNATIONAL ISO
STANDARD 8031
Third edition
2009-10-15
Rubber and plastics hoses and hose
assemblies — Determination of electrical
resistance and conductivity
Tuyaux et flexibles en caoutchouc et en plastique — Détermination de
la résistance et de la conductivité électriques

Reference number
ISO 8031:2009(E)
©
ISO 2009
ISO 8031:2009(E)
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ii © ISO 2009 – All rights reserved

ISO 8031:2009(E)
Contents Page
Foreword .iv
Introduction.v
1 Scope.1
2 Normative references.1
3 Terms and definitions .1
4 Measurement of resistance of conductive, antistatic and non-conductive hoses.1
4.1 General .1
4.2 Apparatus.2
4.3 Preparation and cleaning for the test.3
4.4 Conditioning .4
4.5 Procedure for hoses with conducting lining (on full hose length).4
4.6 Procedure for hoses with conducting cover .5
4.7 Procedure for hoses with conducting compounds throughout.6
4.8 Hose assemblies fitted with metal end fittings .7
4.9 Test procedure to determine the electrical resistance through the wall of hoses and hose
assemblies .7
5 Measurement of electrical continuity between metal end fittings of hose assemblies .10
6 Measurement of electrical discontinuity of hose assemblies .10
7 Measurement of electrical resistance of a hose assembly lining (conductive or static
dissipating) or hose assembly cover (conductive or static dissipating) in contact with the
metal end fitting.11
7.1 General .11
7.2 Apparatus.11
7.3 Preparation and cleaning for the test.11
7.4 Conditioning .11
7.5 Test procedure.11
8 Test report.13
Annex A (informative) Recommended terminology and limits for electrical conductivity and
resistance.15

ISO 8031:2009(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 8031 was prepared by Technical Committee ISO/TC 45, Rubber and rubber products, Subcommittee
SC 1, Hoses (rubber and plastics).
This third edition cancels and replaces the second edition (ISO 8031:1993), which has been technically
revised (for details, see the Introduction).

iv © ISO 2009 – All rights reserved

ISO 8031:2009(E)
Introduction
This edition of ISO 8031 addresses the problems encountered in field testing and during product acceptance
tests in a production facility in following the test procedures specified in the previous edition (ISO 8031:1993)
and a more practical approach is suggested. Also, a test procedure for determining electrical continuity
between the end fittings of a hose assembly without actually measuring the resistance has been introduced.
This test is frequently carried out in the field and in the factory when the product standard does not require the
exact electrical resistance to be measured, but only requires verification of electric conductivity between both
metal end fittings.
Special test methods to determine the electrical resistance through the hose wall (now required in some
product standards for hoses used in explosive atmospheres) have been added.
Some test methods which have been standard practice in the hose industry for some time have now been
included, as have several new methods to determine the ability of a hose assembly (with metal end fittings) to
dissipate static electric charges when the metal end fitting is connected to earth. A total of four new
explanatory sketches are included. The hose and hose assembly product standard applicable will have to
specify which method is most suitable for the purpose of verification of the required property.
Annex A, an amended version of informative Annex A, “Recommended terminology and limits for electrical
resistance”, in ISO 8330:2007, has been included.

INTERNATIONAL STANDARD ISO 8031:2009(E)

Rubber and plastics hoses and hose assemblies —
Determination of electrical resistance and conductivity
1 Scope
This International Standard specifies electrical test methods for rubber and plastics hoses, tubing and hose
assemblies to determine the resistance of conductive, antistatic and non-conductive hoses and the electrical
continuity or discontinuity between metal end fittings.
NOTE All the test methods described for rubber hoses in this International Standard can also be applied to plastics
hoses.
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 2878, Rubber — Antistatic and conductive products — Determination of electrical resistance
ISO 8330, Rubber and plastics hoses and hose assemblies — Vocabulary
ISO 23529, Rubber — General procedure for preparing and conditioning test pieces for physical test methods
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 8330 apply.
4 Measurement of resistance of conductive, antistatic and non-conductive hoses
4.1 General
Rubber hoses may have a conducting lining only or a conducting cover only, or may be manufactured from
conducting rubber compounds throughout. A method of test is specified for each of the three possible types of
construction.
ISO 8031:2009(E)
4.2 Apparatus
The following apparatus is required and shall be basically as described in ISO 2878.
4.2.1 Test instruments
1)
4.2.1.1 To determine the resistance of conductive, antistatic and non-conductive hose , the test should
preferably be made with an instrument specifically designed for measuring insulation resistance, having a
nominal open-circuit voltage of 500 V d.c., or with any other instrument known to give comparable results. The
instrument shall be sufficiently accurate to determine the resistance to within ± 10 % unless specified
otherwise. During the test, not more than 3 W shall be dissipated in the specimen, to prevent erroneous
results due to effects of temperature. The power dissipated shall be determined by the square of the open-
circuit voltage divided by the measured resistance.
The resistance values obtained will vary with the applied voltage, and errors may occur when low test voltages
are involved. In cases of dispute, the voltage applied to the test piece shall be not less than 40 V, except
where this conflicts with the requirement not to dissipate more than 3 W in the test piece.
4.2.1.2 For tests requiring the measurement of the electrical continuity between end fittings or through
continuous internal or external bonded wires, the instrument used shall be an ohmmeter sufficiently accurate
to determine the resistance to within ± 10 %.
4.2.1.3 For tests where, according to the product standard, determination of the electrical continuity
between the end fittings of a hose assembly is required, without measurement of the actual electrical
resistance, a 4,5 V battery in combination with a 4 V (0,3 A) test lamp can be used.
4.2.1.4 For determination of the electrical resistance through the hose wall (required by some hose
product standards for hoses used in explosive atmospheres), the instrument used shall be an ohmmeter with
a capacity of 10 Ω and the measurement shall be made at 500 V d.c. The instrument shall be sufficiently
accurate to determine the resistance between the lining and the cover as measured through the hose wall to
within ± 5 %.
4.2.2 Electrodes and contacts
4.2.2.1 General
For tests conducted in a laboratory, the equipment described below shall be used. For field tests, and for
routine tests and product acceptance tests in a manufacturer's plant, this equipment is not practical, and
alternatives may be used as described in 4.6.1, 4.7.1.2 and 4.7.2.3.
+2
Electrodes shall be formed on the surface as bands 25 mm wide around the circumference by means of a
()−1
conductive silver lacquer, colloidal graphite or a conductive liquid.
When a conductive liquid is used, the electrode contact area shall be completely wetted and shall remain so
until the end of the test. Unless otherwise specified, the conductive liquid shall consist of
⎯ 800 parts by mass of anhydrous poly(ethylene glycol) of relative molecular mass 600;
⎯ 200 parts by mass of water;
⎯ 1 part by mass of wetting agent;
⎯ 10 parts by mass of potassium chloride.

1) See ISO 8330 and Annex A of this International Standard for details of construction.
2 © ISO 2009 – All rights reserved

ISO 8031:2009(E)
When a conductive silver lacquer or colloidal graphite is used, the surface resistance between any two points
Ω.
on a sample of the dried film shall not exceed 100
Clean metal contacts shall be applied to the electrodes so that the contact area is approximately the same
size as, but no greater than, the electrodes, except where otherwise stated.
In the case of hoses of less than 50 mm bore, it is difficult to apply the conducting liquid accurately to the hose
bore, and it is preferable to use a brass plug of external diameter equal to or greater than the hose internal
diameter (ID), coated with conducting liquid and then pushed 25 mm into the hose.
4.2.2.2 Special electrodes and contacts
The following special electrodes and contacts shall be used for the determination of the electrical resistance
through the hose wall, and other test methods:
a) Outer electrode: a copper sheet-metal band, of standard width 25 mm, clamped around the outer hose
wall (see Figure 1).
b) Inner electrode:
1) For hoses of less than 50 mm bore size, it is recommended that a tight-fitting brass plug (solid for
small bore sizes and hollow for larger sizes), of minimum length 2 × the pitch of the helical wire(s)
(for hoses incorporating helical wires) or 0,5 × ID (for hoses without helical wires), be used.
2) For hoses of more than 50 mm bore size, it is recommended that an adjustable copper sheet-metal
band, tightly fitting the bore of the hose (expanded against the lining by spring action), of minimum
width 25 mm, be used.
c) Contacts for connecting the electrodes to the ohmmeter should preferably be soldered or brazed to the
electrodes to minimize resistance between ohmmeter and electrode (see Figure 1).
d) Alternative to b): a 25-mm-wide conducting foam plug completely wetted with a suitable conductive liquid
(see 4.2.2.1) of outside diameter slightly larger than the inside diameter of the hose to ensure a snug fit
with good electric contact with the hose lining and connected to a suitable insulated conductor (see
Figure 3, items 1 and 3). This electrode is recommended for use with hoses with corrugated linings or
linings which are less flexible than rubber (i.e. PTFE).
e) In order to establish good electrical contact with the cover of a corrugated hose, it is recommended that a
conducting foam strip 25 mm wide, completely wetted in suitable conductive liquid (see 4.2.2.1), be
placed round the full outside circumference of the hose, underneath the electrode described in item a)
above.
4.3 Preparation and cleaning for the test
The surfaces of the hose or test piece shall be clean. If necessary, they may be cleaned by rubbing with
fuller's earth (magnesium aluminium silicate) and water, washing with distilled water and allowing to dry. Do
not use organic materials which attack the rubber or cause it to swell, and do not buff or abrade the test
surfaces.
The surface of the hose shall not become deformed either during the application of the contacts or during the
test. When using test pieces, the supports shall be outside the test length. When testing a long length of hose,
the hose shall be uncoiled and laid straight on polyethylene or another insulating material. Care shall be taken
to ensure that the hose is insulated from any leakage path along the length of hose.
ISO 8031:2009(E)
a) Outer electrode for all sizes b) Inner electrode for bore sizes > 50 mm
a
To ohmmeter.
Figure 1 — Examples of inner and outer electrodes as described in 4.2.2.2
4.4 Conditioning
Normally, the articles shall be conditioned for at least 16 h under one of the following sets of standard
conditions:
(23 ± 2) °C and (50 ± 5) % relative humidity;
(27 ± 2) °C and (65 ± 5) % relative humidity.
However, where very long lengths of hose are being tested, it is permissible, by agreement between supplier
and customer, to use the conditions prevailing in the factory, warehouse or laboratory, provided that the
relative humidity is not greater than 70 %. For testing in the field and for routine and product acceptance tests
in a manufacturer's factory of short lengths of hose and hose assemblies, this applies as well.
4.5 Procedure for hoses with conducting lining (on full hose length)
Apply suitable electrodes as specified in 4.2.2 on the inside surface at each end of the hose. The edge of the
electrode band shall be coincident with the end of the hose. When using a conductive liquid, care shall be
taken to avoid creating a leakage path between the lining and the reinforcement or cover of the hose.
Apply the metal contacts to the electrodes.
Apply the test voltage and measure the resistance (5 ± 1) s after the application of the voltage.
For field tests and routine and product acceptance tests in the factory, the equipment specified in 4.2.2.1 is
too complicated and impractical. Instead, clean copper or brass contacts at least 100 mm in area, shaped to
fit the inside surface of the hose lining and held in position manually, can be used. Alternatively, suitable
electrodes as described in 4.2.2.2 can be used.
4 © ISO 2009 – All rights reserved

ISO 8031:2009(E)
4.6 Procedure for hoses with conducting cover
4.6.1 Method for full hose lengths
Apply electrodes as specified in 4.2.2.1 on the outside surface at each end of the hose.
Apply the metal contacts.
Apply the test voltage and measure the resistance (5 ±
...