EN 62805-2:2017

Method for measuring photovoltaic (PV) glass - Part 2: Measurement of transmittance and reflectance

IEC 62805-2:2017 specifies methods for measuring the transmittance and reflectance of glass used in photovoltaic (PV) modules and provides instructions on how to calculate the effective hemispherical transmittance and reflectance of this glass. This document is applicable to PV glasses used in PV modules, including ultra-clear patterned glass, anti-reflective coated (AR) glass, transparent conductive oxide coated (TCO) glass and other kinds of PV glass used in PV modules. These test methods are designed to provide reproducible data appropriate for comparison of results among laboratories or at different times by the same laboratory and for comparison of data obtained on different PV glasses.

Verfahren für die Messung von photovoltaischem (PV) Glas - Teil 2: Messung von Transmissionsgrad und Reflexionsgrad

Méthode de mesure du verre photovoltaïque (PV) – Partie 2: Mesurage du facteur de transmission et du facteur de réflexion

L'IEC 62805-2:2017 spécifie des méthodes de mesure du facteur de transmission et du facteur de réflexion du verre utilisé dans les modules photovoltaïques (PV) et fournit des instructions concernant la façon de calculer le facteur de transmission et le facteur de réflexion hémisphériques effectifs dudit verre. Le présent document est applicable aux verres PV utilisés dans les modules PV, y compris le verre imprimé ultra transparent, le verre revêtu d’une couche antireflet, le verre revêtu d’oxyde conducteur transparent (TCO) et les autres types de verres PV utilisés dans les modules PV. Ces méthodes d’essai sont conçues pour fournir des données reproductibles appropriées à des fins de comparaison des résultats fournis par différents laboratoires ou à différentes périodes de temps par le même laboratoire et à des fins de comparaison des données obtenues pour les différents verres PV.

Metode za merjenje fotonapetostnega (PV) stekla - 2. del: Merjenje transmitance in reflektance

Ta del standarda IEC 62805 določa metode za merjenje transmitance in reflektance stekla, ki se uporablja za fotonapetostne module, ter podaja navodila za izračun efektivne polkrožne transmitance in reflektance tega stekla.
Ta dokument se uporablja za fotonapetostno steklo, ki se uporablja za fotonapetostne module, vključno z ultraprozornim ornamentnim steklom, steklom z antireflektivnim (AR) premazom, prosojnim prevodnim steklom z oksidovim premazom (TCO) in drugimi vrstami fotonapetostnega stekla, ki se uporabljajo za fotonapetostne module.
Te preskusne metode so zasnovane za zagotavljanje ponovljivih podatkov, ki so primerni za primerjavo rezultatov med laboratoriji ali ob različnih časih v istem laboratoriju in za primerjavo podatkov, pridobljenih o različnih fotonapetostnih steklih.
Te preskusne metode so se izkazale kot uporabne za steklo z odsevnimi in razpršilnimi optičnimi lastnostmi.

General Information

• Status: Published
• Publication Date: 09-Nov-2017
• Withdrawal Date: 20-Sep-2020
• ICS: 27.160 - Solar energy engineering
• Technical Committee: CLC/TC 82 - Solar photovoltaic energy systems
• Drafting Committee: IEC/TC 82 - IEC_TC_82
• Current Stage: 6060 - Document made available - Publishing
• Start Date: 10-Nov-2017
• Completion Date: 10-Nov-2017
• Ref Project: SIST EN 62805-2:2018 - Method for measuring photovoltaic (PV) glass - Part 2: Measurement of transmittance and reflectance

Overview

EN 62805-2:2017 (IEC 62805-2:2017) defines standardized methods for measuring the transmittance and reflectance of glass used in photovoltaic (PV) modules. The standard targets optical characterization of PV glass types such as ultra‑clear patterned glass, anti‑reflective (AR) coated glass, and transparent conductive oxide (TCO) glass. Measurement and calculation are performed over the PV-relevant spectral range (typically 280–1 250 nm) and are based on spectral photon irradiance (photon flux), enabling results that relate directly to solar cell response and current generation.

Key Topics and Requirements

• Scope and materials: Applies to common PV glasses used in PV modules, including glasses with both specular and diffuse optical behavior.
• Spectral basis: Uses photon irradiance rather than traditional energy-based solar irradiance to calculate effective transmittance and reflectance in the 280–1 250 nm range - the wavelength range relevant to most solar cells.
• Hemispherical values: Specifies measurement and calculation of spectral hemispherical transmittance and spectral hemispherical reflectance, and procedures to compute effective hemispherical quantities weighted by photon flux.
• Apparatus and conditions: Defines instrument requirements and measurement conditions (for example, integrating sphere type and diameter are specified) to ensure reproducible, inter-laboratory comparable data.
• Test procedure elements:
  • Instrument calibration and reference standards
  • Sample conditioning and preparation
  • Measurement sequences for transmittance and reflectance
  • Calculation methods and expression of results
  • Required contents for the test report
• Reproducibility focus: Methods are designed for consistent comparison across laboratories and over time.

Applications and Users

Who benefits from EN 62805-2:

• PV module and PV glass manufacturers - to quantify optical performance (light transmission and reflection) of candidate glasses and coatings.
• Independent testing laboratories and certification bodies - for standardized test methods that support product certification and quality control.
• R&D teams and material scientists - to compare AR and TCO treatments, textured patterns, and new glass formulations on a common basis.
• System designers and performance modelers - to obtain accurate optical inputs for PV module performance simulations and energy yield assessments.

Practical uses:

• Selecting glass with optimal transmittance for higher module efficiency
• Evaluating anti-reflective coatings or patterning effects
• Establishing supplier specifications and acceptance criteria
• Generating comparable lab reports for procurement and certification

Related Standards

• EN/IEC 62805-1:2017 - Measurement of total haze and spectral distribution of haze (companion document)
• IEC 60904-3:2016 - PV device measurement principles with reference spectral irradiance
• IEC 62788-1-4 - Measurement procedures for PV module materials (encapsulants)
• ISO 9050 - Glass in building - related optical property measurements

Keywords: EN 62805-2, IEC 62805-2, photovoltaic glass, PV glass transmittance, PV glass reflectance, integrating sphere, photon irradiance, AR glass, TCO glass, PV module testing.

Standards Content (Sample)

SLOVENSKI STANDARD
01-januar-2018
Metode za merjenje fotonapetostnega (PV) stekla - 2. del: Merjenje transmitance in
reflektance
Method for measuring photovoltaic (PV) glass - Part 2: Measurement of transmittance
and reflectance
Ta slovenski standard je istoveten z: EN 62805-2:2017
ICS:
27.160 6RQþQDHQHUJLMD Solar energy engineering
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD EN 62805-2
NORME EUROPÉENNE
EUROPÄISCHE NORM
November 2017
ICS 27.160
English Version
Method for measuring photovoltaic (PV) glass - Part 2:
Measurement of transmittance and reflectance
(IEC 62805-2:2017)
Méthode de mesure du verre photovoltaïque (PV) - Partie 2: Verfahren für die Messung von photovoltaischem (PV) Glas
Mesurage du facteur de transmission et du facteur de - Teil 2: Messung von Transmissionsgrad und
réflexion Reflexionsgrad
(IEC 62805-2:2017) (IEC 62805-2:2017)
This European Standard was approved by CENELEC on 2017-09-21. CENELEC 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-CENELEC
Management Centre or to any CENELEC 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 CENELEC member into its own language and notified to the CEN-CENELEC Management Centre has the
same status as the official versions.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic,
Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden,
Switzerland, Turkey and the United Kingdom.

European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2017 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN 62805-2:2017 E
European foreword
The text of document 82/1298/FDIS, future edition 1 of IEC 62805-2, prepared by IEC/TC 82 “Solar
photovoltaic energy systems" was submitted to the IEC-CENELEC parallel vote and approved by
CENELEC as EN 62805-2:2017.
The following dates are fixed:
(dop) 2018-06-21
• latest date by which the document has to be
implemented at national level by
publication of an identical national
standard or by endorsement
• latest date by which the national (dow) 2020-09-21
standards conflicting with the
document have to be withdrawn
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CENELEC shall not be held responsible for identifying any or all such patent rights.
Endorsement notice
The text of the International Standard IEC 62805-2:2017 was approved by CENELEC as a European
Standard without any modification.
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements 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 1 When an International Publication has been modified by common modifications, indicated by (mod), the relevant

EN/HD applies.
NOTE 2 Up-to-date information on the latest versions of the European Standards listed in this annex is available here:
www.cenelec.eu.
Publication Year Title EN/HD Year
IEC 60904-3 2016 Photovoltaic devices - Part 3: EN 60904-3 2016
Measurement principles for terrestrial
photovoltaic (PV) solar devices with
reference spectral irradiance data
IEC 62788-1-4 -  Measurement procedures for materials EN 62788-1-4 -
used in photovoltaic modules - Part 1-4:
Encapsulants - Measurement of optical
transmittance and calculation of the solar-
weighted photon transmittance, yellowness
index, and UV cut-off frequency
IEC 62805-1 2017 Method for measuring photovoltaic (PV) EN 62805-1 2017
glass - Part 1: Measurement of total haze
and spectral distribution of haze
ISO 9050 -  Glass in building_- Determination of light - -
transmittance, solar direct transmittance,
total solar energy transmittance, ultraviolet
transmittance and related glazing factors

IEC 62805-2 ®
Edition 1.0 2017-08
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Method for measuring photovoltaic (PV) glass –

Part 2: Measurement of transmittance and reflectance

Méthode de mesure du verre photovoltaïque (PV) –

Partie 2: Mesurage du facteur de transmission et du facteur de réflexion

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 27.160 ISBN 978-2-8322-4721-1

– 2 – IEC 62805-2:2017 © IEC 2017
CONTENTS
FOREWORD . 3
INTRODUCTION . 5
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 6
4 Apparatus . 7
4.1 General . 7
4.2 Performance of test instrument . 7
5 Test specimens and reference standards . 7
5.1 Test specimens . 7
5.2 Reference standard . 7
6 Conditioning . 7
7 Procedure . 8
7.1 General . 8
7.2 Measurement of spectral hemispherical transmittance . 8
7.2.1 Instrument calibration . 8
7.2.2 Sample measurement . 8
7.3 Measurement of spectral hemispherical reflectance . 8
7.3.1 Instrument calibration . 8
7.3.2 Sample measurement . 9
8 Calculation and expression of results . 10
8.1 Effective hemispherical transmittance of photon irradiance . 10
8.2 Effective hemispherical reflectance of photon irradiance . 10
9 Test report . 11
Bibliography . 12

Figure 1 – Schematic of the integrating sphere for reflectance measurement . 9

IEC 62805-2:2017 © IEC 2017 – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
METHOD FOR MEASURING PHOTOVOLTAIC (PV) GLASS –

Part 2: Measurement of transmittance and reflectance

FOREWORD
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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 62805-2 has been prepared by IEC technical committee 82: Solar
photovoltaic energy systems.
The text of this standard is based on the following documents:
FDIS Report on voting
82/1298/FDIS 82/1322/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.
A list of all parts in the IEC 62805, published under the general title Method for measuring
photovoltaic (PV) glass, can be found on the IEC website.

– 4 – IEC 62805-2:2017 © IEC 2017
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.
IEC 62805-2:2017 © IEC 2017 – 5 –
INTRODUCTION
This document differentiates from the other standards related to transmittance and reflectance
test as follows:
• the scope of this document is restricted to transmittance and reflectance measurement for
PV glass,
• the wavelength range is typically from 280 nm to 1 250 nm which is related to the spectral
response of common solar cells,
• in order to harmonize the calculation of the transmittance and reflectance of PV glass, the
photon irradiance was used instead of the spectral solar irradiance,
• apparatus conditions such as the integrating sphere type and diameter are specified.
This part of IEC 62805 establishes IEC requirements for providing procedures and calculation
methods for measuring the transmittance and reflectance of glass used in photovoltaic (PV)
modules.
Types of PV glass include ultra-clear patterned glass, anti-reflective coated glass, transparent
conductive oxide (TCO) glass and other kind of glass used in PV modules. With the rapid
growth of the global PV industry, the amount of PV glass being used has increased
tremendously. The optical properties including t
...