IEC 60216-4-1:2006

Electrical insulating materials - Thermal endurance properties - Part 4-1: Ageing ovens - Single-chamber ovens

Covers minimum requirements for ventilated and electrically heated single-chamber ovens, with or without forced gas circulation, for thermal endurance evaluation of electrical insulation. It covers ovens designed to operate over all or part of the temperature range from 20 °C above ambient to 500 °C. It gives acceptance tests and in-service monitoring tests for these ageing ovens. The main changes with regard to the previous edition is that this edition adapts IEC 60216-4-1 to the technical content and the editorial form of IEC 60216-4-2 and IEC 60216-4-3. In addition, errors and omissions in the third edition have been corrected.

General Information

• Status: Published
• Publication Date: 18-Jan-2006
• ICS: 17.220.99 - Other standards related to electricity and magnetism
• ICS: 29.035.01 - Insulating materials in general
• Technical Committee: TC 112 - Evaluation and qualification of electrical insulating materials and systems
• Drafting Committee: WG 1 - TC 112/WG 1
• Current Stage: PPUB - Publication issued
• Start Date: 19-Jan-2006
• Completion Date: 31-May-2006

Overview

IEC 60216-4-1:2006 - "Electrical insulating materials - Thermal endurance properties - Part 4-1: Ageing ovens - Single-chamber ovens" specifies minimum requirements, acceptance tests and in‑service monitoring for ventilated, electrically heated single‑chamber ageing ovens used to determine the thermal endurance of electrical insulating materials. The standard covers ovens designed to operate over all or part of the range from 20 °C above ambient up to 500 °C and aligns editorially and technically with IEC 60216-4-2 and IEC 60216-4-3.

Key topics and technical requirements

• Oven construction: Durable, corrosion‑resistant materials for continuous operation; interior materials must not emit volatiles that affect specimens. Doors must seal effectively; fittings must be accessible for maintenance.
• Ventilation and gas management: Provision for pre‑heated ventilating gas with controlled inlet/exhaust and, where specified, forced circulation. Purity of incoming gas and safety measures (cut‑off/alarm on gas failure) are required.
• Exposure volume: Definition of the chamber region that meets limits for temperature fluctuation, temperature difference and temperature variation; specimen mounting rules to avoid thermal disturbance.
• Temperature control and measurement: Requirements for global average and global exposure temperatures, sensor placement (nine sensors across exposure volume), and limits on temperature fluctuation (δT1), temperature difference (δT2), temperature variation (δTv) and maximum temperature deviation (δTd). The standard provides tables and test procedures for determining compliance.
• Performance parameters: Rate of ventilation (air changes per hour, N), time constant for standard specimens, exposure volume limits, and maximum allowable temperature deviations.
• Testing and monitoring: Acceptance tests, detailed test methods (including Annex A for ventilation), in‑service monitoring procedures and reporting requirements to ensure reliable thermal ageing data.

Practical applications

• Specifying and procuring ageing ovens for thermal endurance testing of insulating materials (epoxies, polymers, varnishes, tape, etc.).
• Establishing laboratory test procedures and acceptance criteria for ovens used in R&D, quality control and qualification testing.
• Supporting accreditation and compliance activities (reference to ISO/IEC 17025:2005 for laboratory competence).
• Minimizing test variability by ensuring correct oven performance (temperature uniformity, controlled ventilation) for repeatable thermal ageing results.
• Informing maintenance, in‑service checks and calibration schedules for test laboratories.

Who should use this standard

• Test laboratories and calibration facilities performing thermal endurance tests on electrical insulating materials.
• Manufacturers of insulating materials and electrical equipment who require validated ageing data.
• Oven manufacturers and suppliers to ensure products meet IEC requirements.
• Certification bodies and quality managers establishing compliance and procurement specifications.

Related standards

• IEC 60216 series (Parts 1–6) - overall thermal endurance methodology.
• IEC 60216-4-2 (precision ovens up to 300 °C) and IEC 60216-4-3 (multi‑chamber ovens) - complementary oven specifications.
• ISO/IEC 17025:2005 (laboratory competence) and IEC 60335 (safety for electrical appliances) - normative references in the document.

Keywords: IEC 60216-4-1, ageing ovens, single-chamber ovens, thermal endurance properties, electrical insulating materials testing, temperature uniformity, ventilation rate, exposure temperature.

Standards Content (Sample)

INTERNATIONAL IEC
STANDARD 60216-4-1
Fourth edition
2006-01
Electrical insulating materials –
Thermal endurance properties –
Part 4-1:
Ageing ovens –
Single-chamber ovens
Reference number
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INTERNATIONAL IEC
STANDARD 60216-4-1
Fourth edition
2006-01
Electrical insulating materials –
Thermal endurance properties –
Part 4-1:
Ageing ovens –
Single-chamber ovens
 IEC 2006  Copyright - all rights reserved
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 the publisher.
International Electrotechnical Commission, 3, rue de Varembé, PO Box 131, CH-1211 Geneva 20, Switzerland
Telephone: [phone] Telefax: [phone] E-mail: [e-mail] Web: www.iec.ch
PRICE CODE
Commission Electrotechnique Internationale Q
International Electrotechnical Commission
МеждународнаяЭлектротехническаяКомиссия
For price, see current catalogue

– 2 – 60216-4-1  IEC:2006(E)
CONTENTS
FOREWORD.3

1 Scope.5
2 Normative references .5
3 Terms and definitions .5
4 Constructional requirements .7
4.1 General .7
4.2 Mechanical requirements.7
4.3 Ventilation .7
4.4 Specimen mounting arrangements .8
4.5 Temperature control and indicator systems .8
5 Performance requirements .8
5.1 Temperature.8
5.2 Temperature difference and temperature fluctuation.9
5.3 Temperature variation .9
5.4 Maximum temperature deviation.9
5.5 Rate of ventilation .9
5.6 Exposure volume.9
5.7 Time constant.10
6 Test methods and procedure .10
6.1 General .10
6.2 Exposure volume.10
6.3 Temperature and related parameters.10
6.4 Rate of ventilation .11
6.5 Time constant.12
7 Report .12
8 Conditions of use and instructions for in-service monitoring by the user .13
8.1 Conditions of use .13
8.2 Procedure .13
8.3 In-service monitoring .13

Annex A (informative) Test method to determine the rate of ventilation .14
Annex B (informative) Examples for calculation of temperature deviation.16

Bibliography.17

Table 1 – Maximum allowable temperature differences and temperature fluctuations.9
Table 2 – Maximum allowable temperature variation .9

60216-4-1  IEC:2006(E) – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
ELECTRICAL INSULATING MATERIALS –
THERMAL ENDURANCE PROPERTIES –

Part 4-1: Ageing ovens –
Single-chamber ovens
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
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between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
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equipment declared to be in conformity with an IEC Publication.
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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 60216-4-1 was prepared by subcommittee 15E: Methods of test, of
IEC technical committee 15: Insulating materials, which has now been merged with IEC
technical committee 98: Electrical insulation systems into IEC technical committee 112:
Evaluation and qualification of electrical insulating materials and systems (provisional title).
This fourth edition of IEC 60216-4-1 cancels and replaces the third edition, published in 1990,
and constitutes a technical revision.
The main changes with regard to the previous edition is that this edition adapts IEC 60216-4-1
to the technical content and the editorial form of IEC 60216-4-2 and IEC 60216-4-3. In
addition, errors and omissions in the third edition have been corrected.

– 4 – 60216-4-1  IEC:2006(E)
The text of this standard is based on the following documents:
FDIS Report on voting
112/16/FDIS 112/23/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
IEC 60216, under the general title Electrical insulating materials – Thermal endurance
properties, is composed of several parts:
Part 1: Ageing procedures and evaluation of test results
Part 2: Determination of thermal endurance properties of electrical insulating materials –
Choice of test criteria
Part 3: Instructions for calculating thermal endurance characteristics
Part 4-1: Ageing ovens – Single-chamber ovens
Part 4-2: Ageing ovens – Precision ovens for use up to 300 °C
Part 4-3: Ageing ovens – Multi-chamber ovens
Part 5: Determination of relative thermal endurance index (RTE) of an insulating material
Part 6: Determination of thermal endurance indices (TI and RTE) of an insulating material
using the fixed time frame method
The committee has decided that the contents of this publication will remain unchanged until
the maintenance result date indicated on the IEC web site under "http://webstore.iec.ch" in
the data related to the specific publication. At this date, the publication will be
• reconfirmed;
• withdrawn;
• replaced by a revised edition, or
• amended.
A bilingual version of this publication may be issued at a later date.

___________
For revisions and new parts, see the current catalogue of IEC publications for an up-to-date list.

60216-4-1  IEC:2006(E) – 5 –
ELECTRICAL INSULATING MATERIALS –
THERMAL ENDURANCE PROPERTIES –

Part 4-1: Ageing ovens –
Single-chamber ovens
1 Scope
This part of IEC 60216 covers minimum requirements for ventilated and electrically heated
single-chamber ovens, with or without forced gas circulation, for thermal endurance
evaluation of electrical insulation. It covers ovens designed to operate over all or part of the
temperature range from 20 °C above ambient to 500 °C. It gives acceptance tests and in-
service monitoring tests for these ageing ovens.
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/IEC 17025:2005 General requirements for the competence of testing and calibration
laboratories
IEC 60335 (all parts), Household and similar electrical appliances – Safety
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
rate of ventilation
N
number of air changes per hour in the exposure chamber at room temperature
3.2
exposure volume
that central part of the exposure chamber that meets the requirements for temperature
fluctuation, temperature difference and temperature variation
3.3
exposure temperature
T
temperature selected for ageing test specimens to obtain data for the determination of effects
of temperature
NOTE See also “global exposure temperature”.
3.4
temperature fluctuation
δT
maximum change in temperature at one point in the exposure volume over a period of time

– 6 – 60216-4-1  IEC:2006(E)
3.5
temperature difference
δT
maximum difference of temperature between any two points in the exposure volume at any
one time
3.6
temperature variation
δT
v
difference between the highest temperature and the lowest temperature measured in the
exposure volume over a period of time
3.7
global average temperature
average temperature, calculated from the results of determinations made over a period of at
least 3 h using nine sensors spaced throughout the exposure volume of the chamber
3.8
global exposure temperature
considered to be equal to the global average temperature if the sensors are mounted in the
same space as that containing the specimens
NOTE The term ‘global exposure temperature’ is frequently abbreviated to ‘exposure temperature’.
3.9
time constant (of a standard specimen)
measure of time taken for the temperature of a standard specimen to approach the exposure
volume temperature
3.10
temperature deviation
δT
d
calculated difference in the exposure temperature from the intended value due to the
combination of the temperature difference, temperature fluctuation and the error in the
measurement of temperature
NOTE Examples for calculation of temperature deviation are given in Annex B.
3.11
ventilation
continuous passage of pre-heated gas through the exposure chamber
3.12
standard oven
oven which meets the requirements of this standard
3.13
precision oven
oven with an electrically heated and ventilated chamber and with the ability to maintain the
exposure temperature in its exposure volume within the limits given in IEC 60216-4-2
NOTE The limits for temperature difference and temperature fluctuation in the exposure volume given in this
standard are looser than those given in IEC 60216-4-2.
3.14
oven chamber
interior volume of a single chamber oven providing the space for exposing test specimens or
accommodating an iso-box (see 3.15)

60216-4-1  IEC:2006(E) – 7 –
3.15
iso box
metal box with a close fitting door, mounted in the oven chamber and used as an exposure
chamber to reduce the temperature deviation present in the un-modified oven chamber (see
IEC 60216-4-2)
4 Constructional requirements
4.1 General
The oven shall be soundly constructed of suitable materials designed for continuous operation
over the whole of the allowable temperature range.
All electrical and other ancillary fittings shall be readily accessible for maintenance purposes.
NOTE This standard does not cover all safety aspects. Additional information may be found in the IEC 60335
series.
4.2 Mechanical requirements
The materials of construction of the oven chamber and the interior fittings shall be chosen as
to not influence the properties of the specimens.
NOTE Aluminium alloys and stainless steel have been found suitable in many cases. Copper based alloys and
any materials that may give off interfering volatiles over the temperature range of the oven, for example some
silicone resins, must not be used.
The interior of the oven shall be constructed of suitable corrosion-resistant, non-absorbent
material, so fabricated that any joints are leak-proof and not subject to corrosion. The interior
surfaces shall be easy to clean.
Attention shall be given to ensure that the door to the oven chamber is provided with an
efficient seal and that any gasket materials used do not influence the properties of the
specimens.
4.3 Ventilation
The oven chamber shall be provided with a supply of pre-heated ventilating gas, passing the
chamber at one side and being exhausted through another. Wherever possible, the ventilating
gas shall be directed in such a manner as to produce mixing of the ventilated gas throughout
the chamber.
The rate of ventilation available shall be in accordance with 5.5
Consideration shall be given to ensure adequate purity of the incoming ventilating gas to
minimize influence on the results.
If specified, inlet vents shall enable air and/or other gases to be supplied from controlled
sources.
The construction shall be fitted with equipment to switch off the oven and preferably activate
an alarm when the supply of ventilating gas fails.
NOTE It is recommended that the exhaust from the oven chamber be vented to outside atmosphere, but
precautions should be taken to ensure that volatiles produced by ageing specimens do not damage health or the
environment.
– 8 – 60216-4-1  IEC:2006(E)
4.4 Specimen mounting arrangements
Provision shall be made for supporting/suspending and positioning specimens within the
exposure volume. The specimens shall neither touch each other nor touch the chamber walls.
The specimens and supports shall not occupy more than 25 % of the cross-sectional area of
the chamber in any one plane, nor occupy more than 10 % of the effective working volume of
the chamber.
NOTE If there is an expectation in practice that any of these maxima could be exceeded, the supplier and
purchaser should agree with the user on whether dummy loads should be used during the assessment of
performance.
4.5 Temperature control and indicator systems
The temperature in the exposure volume shall be controllable to the limits given in Clause 5.
The oven chamber shall be fitted with a minimum of two temperature sensors (numbered 1
and 2). Before installation, the sensors 1 and 2 shall be calibrated by reference to a suitable
standard (sensor 3) to give a maximum measurement uncertainty within ±1,0 K. The
difference in reading between the two sensors as a function of temperature shall be recorded.
Sensor 3 shall have a maximum uncertainty of ±0,5 K.
Temperature sensor 1 shall be mounted in a convenient manner, and used to indicate the
chamber temperature.
NOTE 1 It is recommended that the temperature should be recorded during the whole test procedure. The readout
also allows early identification of any malfunction in the system.
Temperature sensor 2 shall be mounted as closely as possible to where the test specimens
will be located. Its placement shall be well defined and reproducible. It may be removed after
the measurements.
An independent sensor may be used to control the temperature. The placing of that sensor
shall be at the manufacturer's discretion. The control system shall have a drift rate of less
than 2 K/year.
NOTE 2 The sensors may be of any type that meets the requirements (for example liquid-filled thermometer,
resistance thermometer).
NOTE 3 Since the performance of thermocouples is less
...