IEC 62788-6-2:2020

IEC 62788-6-2 ®
Edition 1.0 2020-03
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Measurement procedures for materials used in photovoltaic modules –
Part 6-2: General tests – Moisture permeation testing of polymeric materials

Procédures de mesure des matériaux utilisés dans les modules
photovoltaïques –
Partie 6-2: Essais génériques – Essais de perméation à l’humidité des matériaux
polymères
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IEC 62788-6-2 ®
Edition 1.0 2020-03
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Measurement procedures for materials used in photovoltaic modules –

Part 6-2: General tests – Moisture permeation testing of polymeric materials

Procédures de mesure des matériaux utilisés dans les modules

photovoltaïques –
Partie 6-2: Essais génériques – Essais de perméation à l’humidité des matériaux

polymères
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 27.160 ISBN 978-2-8322-7921-2

– 2 – IEC 62788-6-2:2020 © IEC 2020
CONTENTS
FOREWORD . 3
INTRODUCTION . 5
1 Scope . 6
2 Normative references . 6
3 Terms, definitions and symbols. 7
3.1 Terms and definitions . 7
3.2 Symbols . 7
4 Apparatus . 8
5 Test specimens . 8
6 Procedure . 9
7 Calculations . 10
7.1 Determination of diffusivity and solubility of moisture . 10
7.2 Determination of breakthrough constant . 11
7.3 Variable temperature measurement . 12
7.4 Variable relative humidity measurement . 13
8 Test report . 13
Annex A (informative) Example data . 15
A.1 Example of Fickian diffusion . 15
A.2 Example of failed measurement of Fickian diffusion . 16
A.3 Example of non-Fickian diffusion . 17
Bibliography . 19

Figure 1 – Diagram of a diffusion cell . 9
Figure A.1 – Example of Fickian diffusion in EVA at 85 °C and 100 % RH with a 2,84
mm thick film . 16
Figure A.2 – Example of a failed data set for Fickian diffusion in polyethylene
terepthalate at 22 °C and 100 % RH . 17
Figure A.3 – Example of non–Fickian diffusion in a desiccant filled polyisobutylene
material used as an edge seal . 18

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
MEASUREMENT PROCEDURES FOR MATERIALS
USED IN PHOTOVOLTAIC MODULES –

Part 6-2: General tests –
Moisture permeation testing of polymeric materials

FOREWORD
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International Standard IEC 62788-6-2 has been prepared by IEC technical committee 82: Solar
photovoltaic energy systems.
The text of this International Standard is based on the following documents:
FDIS Report on voting
82/1659/FDIS 82/1690/RVD
Full information on the voting for the approval of this International Standard can be found in the
report on voting indicated in the above table.
This document has been drafted in accordance with the ISO/IEC Directives, Part 2.

– 4 – IEC 62788-6-2:2020 © IEC 2020
A list of all parts in the IEC 62788 series, published under the general title Measurement
procedures for materials used in photovoltaic modules, can be found on the IEC website.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under "http://webstore.iec.ch" in the data related to
the specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
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INTRODUCTION
This part of IEC 62788 describes methods to measure the permeation properties of polymeric
materials. The degr
...