CLC/TS 61112:2006

SLOVENSKI STANDARD
01-marec-2007
Pregrinjala iz izolacijskega materiala za uporabo v elektrotehniki (IEC 61112:1992 +
A1:2002 + popravek maj 2000 + A1:2002)
Blankets of insulating material for electrical purposes (IEC 61112:1992 + A1:2002 +
corrigendum May 2000 + A1:2002)
Abdecktcher aus isolierendem Material zum Arbeiten unter Spannung
Nappes en matriau isolant pour travaux lectriques
Ta slovenski standard je istoveten z: CLC/TS 61112:2006
ICS:
13.260 9DUVWYRSUHGHOHNWULþQLP Protection against electric
XGDURP'HORSRGQDSHWRVWMR shock. Live working
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

TECHNICAL SPECIFICATION
CLC/TS 61112
SPÉCIFICATION TECHNIQUE
December 2006
TECHNISCHE SPEZIFIKATION
ICS 13.260; 29.240.20; 29.260.99

English version
Blankets of insulating material for electrical purposes
(IEC 61112:1992 + corrigendum May 2000 + A1:2002)

Nappes en matériau isolant  Abdecktücher aus isolierendem Material
pour travaux électriques zum Arbeiten unter Spannung
(CEI 61112:1992 (IEC 61112:1992
+ corrigendum mai 2000 + A1:2002) + Corrigendum Mai 2000 + A1:2002)

This Technical Specification was approved by CENELEC on 2006-09-02.

CENELEC members are required to announce the existence of this TS in the same way as for an EN and to
make the TS available promptly at national level in an appropriate form. It is permissible to keep conflicting
national standards in force.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Cyprus, the Czech
Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain,
Sweden, Switzerland and the United Kingdom.

CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung

Central Secretariat: rue de Stassart 35, B - 1050 Brussels

© 2006 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. CLC/TS 61112:2006 E
Foreword
The text of the International Standard IEC 61112:1992 + corrigendum May 2000 + A1:2002, prepared by
IEC TC 78, Live working, was submitted to the formal vote and was approved by CENELEC as
CLC/TS 61112 on 2006-09-02.
The following date was fixed:
– latest date by which the existence of the CLC/TS
has to be announced at national level (doa) 2007-03-01
Annex ZA has been added by CENELEC.
___________
Endorsement notice
The text of the International Standard IEC 61112:1992 + corrigendum May 2000 + A1:2002 was approved
by CENELEC as a Technical Specification without any modification.
___________
- 3 - CLC/TS 61112:2006
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications

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.

NOTE  When an international publication has been modified by common modifications, indicated by (mod), the relevant EN/HD
applies.
Publication Year Title EN/HD Year

IEC 60050-121 1978 International Electrotechnical vocabulary - -
(IEV)
Chapter 121: Electromagnetism
IEC 60050-151 1978 International Electrotechnical Vocabulary - -
(IEV)
Part 151: Electrical and magnetic devices

IEC 60050-601 1985 International Electrotechnical Vocabulary - -
(IEV)
Chapter 601: Generation, transmission and
distribution of electricity - General

IEC 60060-1 1989 High-voltage test techniques
+ corr. March 1990 Part 1: General definitions and test HD 588.1 S1 1991
requirements
IEC 60060-3 1976 High-voltage test techniques - -
Part 3: Measuring devices
IEC 60160 1963 Standard atmospheric conditions for test - -
purposes
IEC 60212 1971 Standard conditions for use prior to and HD 437 S1 1984
during the testing of solid electrical insulating
materials
IEC 60417 Data Graphical symbols for use on equipment - -
base
IEC 61318 1994 Live working - Guidelines for quality - -
assurance plans
ISO 472 1988 Plastics - Vocabulary - -

1)
ISO 2592 1973 Petroleum products - Determination of EN 22592 1993
flash and fire points - Cleveland open cup
method
1)
EN 22592 is superseded by EN ISO 2592:2001, which is based on ISO 2592:2000.

Publication Year Title EN/HD Year
ISO 2859-1 1999 Sampling procedures for inspection by - -
attributes
Part 1: Sampling schemes indexed by
acceptance quality limit (AQL) for lot-by-lot
inspection
2)
ISO 2977 1989 Petroleum products and hydrocarbon - -
solvents - Determination of aniline point and
mixed aniline point
3)
ISO 3104 1976 Petroleum Products - Transparent and - -
opaque liquids - Determination of kinematic
viscosity and calculation of dynamic viscosity

4)
ISO/IEC 9000 1987 Quality management and quality assurance EN 29000 1987
standards - Guidelines for selection and use

5)
ISO/IEC 9001 1987 Quality systems - Model for quality EN 29001 1987
assurance in design/development,
production, installation and servicing

6)
ISO/IEC 9002 1987 Quality systems - Model for quality EN 29002 1987
assurance in production and installation

7)
ISO/IEC 9003 1987 Quality systems - Model for quality EN 29003 1987
assurance in final inspection and test

2)
ISO 2977 is superseded by ISO 2977:1997.
3)
ISO 3104 is superseded by ISO 3104:1994, which is harmonized as EN ISO 3104:1996.
4)
EN 29000 is superseded by EN ISO 9000:2005, which is based on ISO 9000:2005.
5)
EN 29001 is superseded by EN ISO 9001:2000, which is based on ISO 2001:2000.
6)
EN 29002 is superseded by EN ISO 9002:1994, which is based on ISO 9002:1994.
7)
EN 29003 is superseded by EN ISO 9003:1994, which is based on ISO 9003:1994.

NORME CEI
INTERNATIONALE IEC
INTERNATIONAL
Edition 1.1
STANDARD
2002-06
Edition 1:1992 consolidée par l'amendement 1:2002
Edition 1:1992 consolidated with amendment 1:2002
Nappes en matériau isolant
pour travaux électriques
Blankets of insulating material
for electrical purposes
 IEC 2002 Droits de reproduction réservés  Copyright - all rights reserved
Aucune partie de cette publication ne peut être reproduite ni No part of this publication may be reproduced or utilized in
utilisée sous quelque forme que ce soit et par aucun procédé, any form or by any means, electronic or mechanical,
électronique ou mécanique, y compris la photocopie et les including photocopying and microfilm, without permission in
microfilms, sans l'accord écrit de l'éditeur. writing from the publisher.
International Electrotechnical Commission 3, rue de Varembé Geneva, Switzerland
Telefax: +41 22 919 0300 e-mail: inmail@iec.ch IEC web site http://www.iec.ch
CODE PRIX
Commission Electrotechnique Internationale
CH
PRICE CODE
International Electrotechnical Commission
Pour prix, voir catalogue en vigueur
For price, see current catalogue

61112 © IEC:1992+A1:2002 – 3 –
CONTENTS
FOREWORD.7
1 Scope .9
1.1 Classes .9
1.2 Categories.9
2 Normative references.9
3 Definitions.11
4 Composition.13
5 Classification .13
6 Physical requirements.15
6.1 Shape .15
6.2 Dimensions .15
6.3 Thickness.15
6.4 Workmanship and finish .17
6.5 Marking .17
6.6 Packaging .19
7 Tests on blankets.19
7.1 General .19
7.2 Visual inspection and measurements.21
7.3 Mechanical tests .23
7.4 Dielectric tests .27
7.5 Ageing tests .35
7.6 Thermal tests .37
8 Tests on blankets with special properties .39
8.1 General .39
8.2 Category A: Acid resistance .39
8.3 Category H: Oil resistance.39
8.4 Category Z: Ozone resistance .41
8.5 Category M: Mechanical (higher level resistance).41
8.6 Category S: Oil and ozone resistance.43
8.7 Category C: Extreme low temperature .43
9 Quality assurance plan and acceptance test .43
Annex A (normative) Marking symbol double triangle .45
Annex B (normative) List and classification of tests.47
Annex C (normative) Oil for tests on category H blankets
Oil resistance.49
Annex D (normative) Sampling plans and procedures .51
Annex E (informative) Guidelines for the selection of the class of blankets in relation
to nominal voltage of a system.55
Annex F (informative) Acceptance tests .57
Annex G (informative) In-service recommendations .59

61112 © IEC:1992+A1:2002 – 5 –
Figure A.1 – Symbols and symbol location.45
Figure 1 – Plain design .61
Figure 2 – Slotted design .61
Figure 3 – Dumb-bell test piece (see 7.3.2).63
Figure 4 – Mechanical puncture (see 7.3.3) .65
Figure 5 – Tear resistance test .67
Figure 6 – Test electrode for blankets of classes 3 and 4.69
Figure 7 – Electrode for plastomers .71
Figure 8 – Polyethylene plates for extreme low temperatures (see 7.2.2 or 8.7).71
Figure 9 – Test set-up – Method B (see 8.4.2) .73
Table 1 – Designation of special properties.15
Table 2 – Recommended dimensions and tolerances.15
Table 3 – Maximum thickness .15
Table 4 – Electrode clearance for proof tests .27
Table 5 – Test voltage .35
Table B.1 – General test procedure .47
Table C.1 – Characteristics of oil .49
Table D.1 – Classification of defects .51
Table D.2 – Sampling plan for minor defects.53
Table D.3 – Sampling plan for major defects.53
Table E.1 – Designation maximum use voltage .55

61112 © IEC:1992+A1:2002 – 7 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
BLANKETS OF INSULATING MATERIAL FOR ELECTRICAL PURPOSES

FOREWORD
1) The IEC (International Electrotechnical Commission) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of the IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, the IEC publishes International Standards. Their preparation is
entrusted to technical committees; any IEC National Committee interested in the subject dealt with may
participate in this preparatory work. International, governmental and non-governmental organizations liaising
with the IEC also participate in this preparation. The IEC collaborates closely with the International
Organization for Standardization (ISO) in accordance with conditions determined by agreement between the
two organizations.
2) The formal decisions or agreements of the IEC on technical matters express, as nearly as possible, an
international consensus of opinion on the relevant subjects since each technical committee has representation
from all interested National Committees.
3) The documents produced have the form of recommendations for international use and are published in the form
of standards, technical specifications, technical reports or guides and they are accepted by the National
Committees in that sense.
4) In order to promote international unification, IEC National Committees undertake to apply IEC International
Standards transparently to the maximum extent possible in their national and regional standards. Any
divergence between the IEC Standard and the corresponding national or regional standard shall be clearly
indicated in the latter.
5) The IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with one of its standards.
6) Attention is drawn to the possibility that some of the elements of this International Standard may be the subject
of patent rights. The IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 61112 has been prepared by IEC technical committee 78: Tools
for live working.
This consolidated version of IEC 61112 consists of the first edition (1992) [documents
78(CO)64/FDIS and 78(CO)68/RVD], its corrigendum May 2000 and its amendment 1 (2002)
[documents 78/437/FDIS and 78/458/RVD].
The technical content is therefore identical to the base edition and its amendment and has
been prepared for user convenience.
It bears the edition number 1.1.
A vertical line in the margin shows where the base publication has been modified by
corrigendum and amendment 1.
Annexes A, B, C and D form an integral part of this International Standard.
Annexes E, F and G are for information only.
The committee has decided that the contents of the base publication, its corrigendum and its
amendment will remain unchanged until 2004. At this date, the publication will be
• reconfirmed;
• withdrawn;
• replaced by a revised edition, or
• amended.
61112 © IEC:1992+A1:2002 – 9 –
BLANKETS OF INSULATING MATERIAL FOR ELECTRICAL PURPOSES
1 Scope
This International Standard is applicable to insulating blankets for the protection of workers
from accidental contact with live or earthed electrical conductors, apparatus or circuits and
avoidance of short circuits on a.c. and d.c. installations.
1.1 Classes
Five classes of blankets, differing in electrical characteristics, are provided and designated as
class 0, class 1, class 2, class 3 and class 4.
1.2 Categories
Six categories of blankets different in properties related to acid, oil, ozone, mechanical
puncture and a combination of oil and ozone are provided and designated categories A, H, Z,
M, S respectively, and also extreme low temperature designated category C.
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.
IEC 60050(121):1978, International Electrotechnical Vocabulary (IEV) Chapter 121: Electro-
magnetism
IEC 60050(151):1978, International Electrotechnical Vocabulary (IEV) Chapter 151:
Electrical and magnetic devices
IEC 60050(601):1985, International Electrotechnical Vocabulary (IEV) Chapter 601: Gener-
ation, transmission and distribution of electricity – General
IEC 60060-1:1989, High-voltage test techniques – Part 1: General definitions and test
requirements
IEC 60060-3:1976, High-voltage test techniques – Part 3: Measuring devices
IEC 60160:1963, Standard atmospheric conditions for test purposes
IEC 60212:1971, Standard conditions for use prior to and during the testing of solid elec-
trical insulating materials
IEC 60417 (all parts), Graphical symbols for use on equipment
IEC 61318:1994, Live working – Guidelines for quality assurance plans

61112 © IEC:1992+A1:2002 – 11 –
ISO 472:1988, Plastics – Vocabulary. Bilingual edition
ISO 2592:1973, Petroleum products – Determination of flash and fire points – Cleveland
open cup method
ISO 2859-1:1999, Sampling procedures for inspection by attributes – Part 1: Sampling
schemes indexed by acceptance quality limit (AQL) for lot-by-lot inspection
ISO 2977:1989, Petroleum products and hydrocarbon solvents – Determination of aniline
point and mixed aniline point
ISO 3104:1976, Petroleum products – Transparent and opaque liquids – Determination of
kinematic viscosity and calculation of dynamic viscosity
ISO 9000:1987, Quality management and quality assurance standards – Guidelines for
selection and use
ISO 9001:1987, Quality systems – Model for quality assurance in design/development,
production, installation and servicing
ISO 9002:1987, Quality systems – Model for quality assurance in production and installation
ISO 9003:1987, Quality systems – Model for quality assurance in final inspection and test
3 Definitions
For the purpose of this International Standard, the following definitions apply.
3.1
elastomer
a generic term that includes rubbers, latex and elastomeric compounds that may be natural,
or synthetic, or a mixture, or a combination of both
3.2
plastic
a material which contains as an essential ingredient a high polymer and which at some stage
of its processing into finished products can be shaped by flow
[ISO 472]
3.3
electrode clearance
the shortest path from the energized electrode to the ground electrode
3.4
electrical puncture
a disruptive breakdown through a solid insulant
[IEV 121-03-13]
3.5
flashover
an arc by-passing an insulating body [IEV 121-03-14] and occurring between electrodes and
over or around, but not through, the equipment being tested

61112 © IEC:1992+A1:2002 – 13 –
3.6
nominal voltage
a suitable approximate value of voltage used to designate or identify a system
[IEV 601-01-21]
3.7
acceptance test
a contractual test to prove to the customer that the device meets certain conditions of its
specification
[IEV 151-04-20]
3.8
proof test voltage
the specified voltage that is applied to a device for the time defined under specified conditions
to assure that the electrical strength of the insulation is above a specified value
3.9
type test
a test of one or more devices made to a certain design to show that the design meets certain
specifications
[IEV 151-04-15]
3.10
routine test
a test to which each individual device is subjected during or after manufacture to ascertain
whether it complies with certain criteria
[IEV 151-04-16]
3.11
sampling test
a test performed on a number of devices taken at random from a batch
[IEV 151-04-17]
3.12
withstand test voltage
the voltage that the device must withstand without flashover, disruptive discharge, puncture or
other electric failure when voltage is applied under specified conditions
4 Composition
The blankets shall be manufactured of elastomer or plastics and produced by seamless
process. Where eyelets are provided in blankets they shall be non-conductive and shall be
nominally 8 mm in diameter.
5 Classification
The blankets covered under this standard shall be designated as follows:
– by class as class 0, class 1, class 2, class 3 and class 4;
– by category by the addition of a suffix as shown in table 1.
Guidance as to use of blankets in relation to nominal voltage of a system is given in annex E.
Guidance as to temperature range at which blankets can be used is given in annex G.

61112 © IEC:1992+A1:2002 – 15 –
Table 1 – Designation of special properties
Category Characteristics
A Resistant to acid
H Resistant to oil
Z Resistant to ozone
M Resistant to mechanical puncture (higher level reinforced)
S Resistant to oil and ozone
C Resistant to extreme low temperatures
NOTE 1 Category S combines the characteristics of categories H and Z.
NOTE 2 Any combination of categories may be used.
6 Physical requirements
6.1 Shape
Blankets may be either of specific shapes or in rolls to be cut for individual requirements.
Those of specific shapes may be plain (see figure 1) or of the slotted design (see figure 2).
6.2 Dimensions
Dimensions and tolerances are indicated in table 2.
Table 2 – Recommended dimensions and tolerances
Dimensions**
Plain Slotted Rolls
Length Width Length Width Width
mm mm mm mm mm
910 305 – – 60*, 90*, 1 000,
560 560  560  560 1 300, 2 000
910 690  910  910
910 910 – –
2 280 910 1 160 1160
* To be produced in class 0 only.
** Permissible variations in length and width shall be ±15 mm except for the 1 160 mm × 1 160 mm slotted size
for which the permissible variation shall be ±25 mm. Permissible variations for rolls of 60 mm and 90 mm in
width shall be ±2 mm.
6.3 Thickness
6.3.1 The maximum thickness of a blanket shall be as given in table 3 in order to obtain
appropriate flexibility.
Table 3 – Maximum thickness
Maximum Maximum
Class Elastomere Plastic
mm mm
0 2,2 1,0
1 3,6 1,5
2 3,8 2,0
1)
3 4,0
1)
4 4,3
1)
Under consideration.
61112 © IEC:1992+A1:2002 – 17 –
6.3.2 The minimum thickness shall be determined only by the ability to pass the tests
defined in clauses 7 and 8.
6.3.3 Blankets of categories A, H, M, S and Z may require additional thickness which shall
not exceed 0,6 mm.
6.4 Workmanship and finish
Blankets shall be free on both surfaces from harmful physical irregularities that can be
detected by thorough test and inspection.
Harmful physical irregularities shall be defined as any feature that disrupts the uniform,
smooth surface contour, such as pinholes, cracks, blisters, cuts, conductive embedded
foreign matter, creases, pinch marks, voids (entrapped air), prominent ripples and prominent
mould marks.
Non-harmful physical irregularities shall be defined as surface irregularities present on either
surface of the blanket due to imperfections on forms or moulds or other imperfections inherent
to the manufacturing process. These irregularities appear as mould marks that look like cuts
even though they are actually a raised ridge of elastomer, indentations, or protuberances that
are acceptable provided that:
a) the depression is not larger than 1,6 mm in diameter, has rounded edges and no visible
break in the surface, and cannot be seen on the opposite side when stretching over the
thumb;
b) there are not more than five depressions as described in a) anywhere on the blanket or on
the roll section under test and any two are separated by at least 15 mm;
c) the indentations, protuberances or mould marks tend to blend into a smooth surface upon
stretching of the material;
d) the small projections or protuberances represent only a small amount of excess material
that cannot be readily removed with the finger and these projections do not appreciably
affect the stretching of the material.
6.5 Marking
6.5.1 Each blanket which is claimed to comply with the requirements of this standard shall
be marked with the following:
a) symbol IEC-60417-5216 – Suitable for live working; double triangle (see annex A);
b) number of the relevant IEC standard immediately adjacent to the symbol;
c) name, trademark, or identification of the manufacturer;
d) category, if applicable;
e) size (length and width);
f) class;
g) month and year of manufacture.
In addition each blanket shall have a group of rectangles or other suitable means to identify
when the blanket was put into service and the dates of periodic inspection and testing.
In the case of rolls and sheets, they shall be marked on one border at least every metre with
the category and class.
61112 © IEC:1992+A1:2002 – 19 –
6.5.2 The marking shall be clearly visible, durable and shall not impair the quality of the
blanket.
The durability of the marking is checked by rubbing the marking for 15 s with a piece of lint-
free cloth soaked in soapy water and then rubbing it for further 15 s with a piece of lint-free
cloth soaked in ethylated alcohol. At the end of the test, the marking must remain legible.
6.5.3 Any additional marking shall be subject to agreement between the manufacturer and
the customer.
6.5.4 When a colour code is used, the colour of the symbol (double triangle) shall corres-
pond to the following code:
Class 0 – red
Class 1 – white
Class 2 – yellow
Class 3 – green
Class 4 – orange
6.6 Packaging
Blankets shall be packaged in an individual container or package of sufficient strength to
properly protect the blankets from damage. The outside of the container or package shall be
marked with the name of the manufacturer or supplier, classification, category, size and
quantity.
At the request of the customer, information contained in annex G and any additional or
amended instructions shall be included in the package.
7 Tests on blankets
7.1 General
There are four kinds of tests: type, routine, sampling and acceptance. These are defined in
clause 3.
Each of the following clauses defines whether type, routine or sampling tests are required.
In order to carry out the type tests, it is necessary to have:
– eight blankets to cover all tests common to all categories of blankets and those for
categories C and M;
– four additional blankets for those of category A;
– four additional blankets for those of category H;
– one additional blanket for those of category Z;
– thirteen blankets to cover all tests of those of category S.
The allotment of these blankets in various testing lots and the order in which these tests are
carried out are given in annex B.
The test location conditions shall be in accordance with IEC 60160, clause 4.

61112 © IEC:1992+A1:2002 – 21 –
Unless otherwise specified, blankets shall be preconditioned for a period of 2 h ± 0,5 h at a
temperature of 23 °C ± 2 °C and relative humidity of 50 % ± 5 % (IEC 60212, Standard
atmosphere B).
In the case of blankets in rolls, the minimum size of each unit shall be 1 m × 1 m. For rolls
of 60 mm and 90 mm in width, the manufacturer shall provide test pieces of 1 m × 1 m.
7.2 Visual inspection and measurements
7.2.1 Shape
Type test and sampling test (see 6.1)
The shape shall be verified by visual inspection.
7.2.2 Dimensions
Type test and sampling test (see 6.2 and figures 1 and 2)
The dimensions as specified in table 2 shall be verified with the blanket in a flattened
condition.
7.2.3 Thickness
Type test and sampling test (see 6.3)
Thickness measurements shall be made at five or more points uniformly distributed over the
total area of the blanket.
Measurements shall be made with a micrometer or any alternative instrument giving sub-
stantially the same results. The micrometer shall be graduated to within 0,02 mm, have an
anvil of 6 mm in diameter, and a flat presser foot 3,17 mm ± 0,25 mm in diameter. The
presser foot shall exert a total force of 0,83 N ± 0,03 N. Sufficient support shall be given to
the blanket so that it will present an unstressed flat surface between the anvil faces of the
micrometer.
In case of dispute, the micrometer method described above shall be used.
7.2.4 Workmanship and finish
Type test and sampling test (see 6.4)
The workmanship and finish shall be verified by visual inspection.
7.2.5 Marking
Type test and routine test (see 6.5)
The marking shall be verified by visual inspection and durability test (see 6.5.2) for type test.
No durability test is required for routine test.
7.2.6 Packaging
Type test and sampling test (see 6.6)
The packaging shall be verified by visual inspection.

61112 © IEC:1992+A1:2002 – 23 –
7.3 Mechanical tests
7.3.1 General
All mechanical tests shall be performed on test pieces which have been conditioned by storing
each blanket separately in a horizontal position for 24 h at a temperature of 23 °C ± 2 °C and
relative humidity of 50 % ± 5 % (see IEC 60212, Standard atmosphere B). The test pieces
shall be cut from samples in two perpendicular directions.
NOTE  The properties of vulcanized elastomeric material change continuously with time, these changes being
particularly rapid in the period immediately following vulcanization.
7.3.2 Tensile strength and elongation at break
Type test and sampling test
Dumb-bell test pieces shall have the outline shown in figure 3 and four shall be cut from the
blanket under test, one near each corner. Two test-pieces shall be cut in length and two in
width.
Reference lines, 20 mm apart, shall be marked on these test pieces, symmetrically placed on
the narrow part of the dumb-bell (see figure 3).
The test pieces shall be tested in a tensile testing machine which shall be power driven at
a sufficient speed to maintain the rate of traverse of the driven grip substantially constant
up to the maximum force capacity of the machine. The rate of traverse shall be 500 mm/min ±
50 mm/min.
The tensile strength shall be calculated by dividing the force at break by the initial area of the
cross section under test. The average of the four test pieces shall not be less than 12 MPa.
The elongation at break shall be calculated by subtracting the initial distance between the
reference lines on the test piece from the distance between the lines at breaking point and
expressing the result as a percentage of the initial distance.
The average of the four test pieces shall not be less than 300 % for elastomers and 150 % for
plastics.
NOTE 1 The machine shall be equipped to give a continuous indication of the force applied to the test piece and
a graduated scale to measure the elongation.
NOTE 2 After the test piece has been broken, the machine shall give a permanent indication of the maximum
force and where possible the maximum elongation.
7.3.3 Mechanical puncture resistance
Type test and sampling test
Two circular test pieces 50 mm in diameter shall be cut from the blanket and each shall be
clamped between two flat 50 mm diameter test plates. The top plate shall have a circular
opening 6 mm in diameter and the bottom plate a 25 mm diameter circular opening. The
edges of both openings shall be rounded to a radius of 0,8 mm (see figure 4).
A needle shall be produced from 5 mm diameter metallic rod and one end shall be machined
to produce a taper with an included angle of 12° and with the tip rounded to a radius of
0,8 mm (see figure 4). The needle shall be clean at the time of use.

61112 © IEC:1992+A1:2002 – 25 –
The needle shall be positioned perpendicularly above the test piece (clamped between
the plates) and shall be driven into and through the specimen. The rate of traverse shall be
500 mm/min ± 50 mm/min. The force required to perform the puncture shall be measured.
The puncture resistance shall be greater than 45 N except for class 0 blankets in which case
it shall be greater than 30 N.
7.3.4 Tension set
Type test and sampling test
This test applies to blankets of elastomer and not to blankets of plastic.
Three test pieces, having the outline shown in figure 3 shall be cut from each blanket under
test. The test pieces shall be fitted in a straining device consisting of a metal rod or other
suitable guide fitted with a pair of holders, one fixed and one moveable, for the ends of the
test piece. The measurement of the unstrained reference length (shown as l in figure 3) shall
o
be checked to the nearest 0,1 mm and the test piece shall be placed in the holder. The test
piece shall be extended at a speed of between 2 mm/s and 20 mm/s to a 200 % ± 10 %
elongation and held for 10 min. After this time the strain shall be released at a speed of
between 2 mm/s and 10 mm/s, and the test piece shall be removed from the holders and laid
free on a flat surface. After a 10 min recovery time the reference length shall be measured
again. The tension set is calculated as a percentage of the initial strain as follows:
I − I
1 o
Tension set = 100 ×
I − I
s o
where
l is the original unstrained reference length
o
l is the strained reference length
s
l is the reference length after recovery
The tension set shall not exceed 15 %.
7.3.5 Tear resistance test
Type test and sampling test
This test applies only to blankets made of plastic.
Four rectangular test pieces, having the outline shown in figure 5, shall be cut, two in length
and two in width. They shall be pre-conditioned at a temperature of 23 °C ± 2 °C and relative
humidity 50 % ± 5 % (see IEC 60212, Standard atmosphere B).
A slit 25 mm ± 0,5 mm long is made in the middle of each test piece beginning the incision at
the centre of the test piece, and two lines drawn with a soft-lead pencil at the location shown
in figure 5. Angle shall be within ±1°.
The test pieces are tested in a tensile testing machine. Two holders larger than the test piece
are set flush with the lines and tightened in order to avoid any slippage.
The testing machine is power driven at a constant speed of 100 mm/min ± 10 mm/min, and
the tensile strength recorded as a function of time.

61112 © IEC:1992+A1:2002 – 27 –
The tensile pressure is increased until the material tears, and the test continued until
complete separation of the two halves.
The maximum tear resistance is taken from the strength/time curve and an average calculated
for all the test pieces. This value shall be greater than 30 N.
7.4 Dielectric tests
7.4.1 General
Dielectric testing shall be carried out either at a.c. or d.c. voltage. The choice of a.c. or d.c.
shall be made between manufacturer and customer.
For type tests three blankets are used. For routine tests one blanket is sufficient. For
sampling tests the number is given in annex D (sample size).
The peak (crest) or r.m.s. value of the a.c. voltage and the arithmetic mean value of the d.c.
voltage shall be measured with an error of not more than 3 % (IEC 60060-3).
For type and sampling tests the blankets shall be conditioned for moisture absorption by
immersion in water for a period of 16 h ± 0,5 h. For routine tests such conditioning is not
required.
Electrodes shall be of such design so as to apply the electrical stress uniformly over the test
area without producing corona at any point or mechanical strain in the material.
The electrodes used in proof tests shall be of such dimensions that the clearances specified
in table 4 are not exceeded.
NOTE  Both a.c. and d.c. test procedures are included in the following clauses. It is intended that one mounting
method and one testing procedure be selected for the electrical acceptance test.
Table 4 – Electrode clearance for proof tests
Clearance for tests
Elastomere Plastic
Class of blankets
For a.c. test For d.c. test For d.c. test
mm mm mm
1)
0 80 80
1)
1 80 80
1)
2 150 250
1) 1)
3 200
1) 1)
4 300
1)
Under consideration.
NOTE  In cases where high humidity (above 55 %) or low barometric pressure (below 99,3 kPa – see IEC 60160)
is encountered, the specified clearances may be increased by a maximum of 50 mm.

61112 © IEC:1992+A1:2002 – 29 –
7.4.2 Electrodes
The different types of electrodes to be employed are described as follows:
7.4.2.1 For a.c. voltage proof test
For classes 0, 1 and 2
Rectangular metal sheets approximately 5 mm thick, having smoothly rounded edges and
corners, of a suitable size, taking into account the clearances shown in table 4. Wet sponges
or conductive foam approximately 6 mm thick are placed between each electrode (rectangular
metal sheet) and the blanket under test. Other electrode designs may be used to achieve the
same results.
For classes 3 and 4
A 1 270 mm × 1 270 mm sheet of insulating material 3 mm to 5 mm thick which has a
762 mm × 762 mm opening in the centre, shall be placed on a grounded metal plate. This
mask, which has a "picture frame" appearance, shall have the opening filled with a conductive
material of such thickness as to bring the ground electrode to approximately the same level as
the mask in order to maintain direct contact with the blanket to be tested.
The blanket is placed over the ground electrode and a wet pad, such as a wet sponge,
approximately the same size as the ground electrode is placed on top of the blanket. The wet
pad is energized with the test voltage (see figure 6)
NOTE 1 This method will test a 762 mm × 762 mm area of a 914 mm × 914 mm blanket at 40 kV a.c. as the mask
prevents flashover.
NOTE 2 For continuous testing of blanket material in roll form, testing may be performed dry.
7.4.2.2 For d.c. voltage proof test
The d.c. proof test may be made with dry electrodes that consist of two flat metallic plates, at
least one of which is sized so that the clearances given in table 4 are not exceeded, or with
the wet electrode. The edges of these plates should be rounded so as to eliminate sharp
nicks and protuberances. Other electrode designs may be used to achieve the same results.
7.4.2.3 For a.c. and d.c. voltage withstand tests
The electrode shall consist of two metal cylinders with the sharp edges removed to give a
radius of 3 mm. One electrode shall be approximately 25 mm in diameter and approximately
25 mm high. The other electrode shall be 75 mm in diameter and approximately 15 mm high.
These electrodes shall be arranged coaxially as in figure 7.
7.4.3 Test equipment
The test equipment used shall be capable of supplying an essentially stepless and contin-
uously variable voltage to the test piece. Motor-driven regulating equipment is convenient and
tends to provide uniform rate-of-rise to the test voltage. The test apparatus shall be protected
by an automatic circuit-breaking device designed to open promptly on the current produced by
failure of the test piece under test. This circuit-breaking device shall be designed to protect
the test equipment under any conditions of short circuit.
NOTE  It is recommended that the test equipment system be inspected and calibrated at least annually.

61112 © IEC:1992+A1:2002 – 31 –
7.4.4 Failure indicators
Blanket failure indicators or accessory circuits shall be designed to give positive indication of
failure.
7.4.5 A.C. voltage test
7.4.5.1 Test equipment
The desired a.c. test voltage can be most readily obtained from a step-up transformer
energized from a variable low voltage source. The transformer and its control equipment shall
be of such size and design that, with the test piece in the circuit, the crest factor or the test
voltage (ratio of maximum to mean effective) shall not differ by more than 5 % from that of the
sinusoidal wave over the upper half of the range of test voltage. Voltage control may be
secured in one of several ways:
a) generator field regulation;
b) variable ratio autotransformer;
c) induction regulator.
NOTE  Voltage controlling equipment should not give rise to voltage distortion and should have an approximately
straight line voltage to time characteristic.
The correct r.m.s. value of the actual sinusoidal voltage waveform applied to the blanket
measured by one of the following methods:
1) a voltmeter used in conjunction with a calibrated instrument transformer connected directly
across the high voltage circuit;
2) a calibrated electrostatic voltmeter connected across the high voltage circuit with a
capacitive divider;
3) a voltmeter connected to a tertiary coil in the test transformer
...