IEC TR 62471-4:2022

IEC TR 62471-4
®


Edition 1.0 2022-09

TECHNICAL
REPORT

colour
inside


Photobiological safety of lamps and lamp systems –
Part 4: Measuring methods
IEC TR 62471-4:2022-09(en)

---------------------- Page: 1 ----------------------
THIS PUBLICATION IS COPYRIGHT PROTECTED
Copyright © 2022 IEC, Geneva, Switzerland

All rights reserved. Unless otherwise specified, 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
either IEC or IEC's member National Committee in the country of the requester. If you have any questions about IEC
copyright or have an enquiry about obtaining additional rights to this publication, please contact the address below or
your local IEC member National Committee for further information.


IEC Secretariat Tel.: +41 22 919 02 11
3, rue de Varembé info@iec.ch
CH-1211 Geneva 20 www.iec.ch
Switzerland

About the IEC
The International Electrotechnical Commission (IEC) is the leading global organization that prepares and publishes
International Standards for all electrical, electronic and related technologies.

About IEC publications
The technical content of IEC publications is kept under constant review by the IEC. Please make sure that you have the
latest edition, a corrigendum or an amendment might have been published.

IEC publications search - webstore.iec.ch/advsearchform IEC Products & Services Portal - products.iec.ch
The advanced search enables to find IEC publications by a Discover our powerful search engine and read freely all the
variety of criteria (reference number, text, technical publications previews. With a subscription you will always have
committee, …). It also gives information on projects, replaced access to up to date content tailored to your needs.
and withdrawn publications.

Electropedia - www.electropedia.org
IEC Just Published - webstore.iec.ch/justpublished
The world's leading online dictionary on electrotechnology,
Stay up to date on all new IEC publications. Just Published
containing more than 22 300 terminological entries in English
details all new publications released. Available online and once
and French, with equivalent terms in 19 additional languages.
a month by email.
Also known as the International Electrotechnical Vocabulary

(IEV) online.
IEC Customer Service Centre - webstore.iec.ch/csc

If you wish to give us your feedback on this publication or need
further assistance, please contact the Customer Service
Centre: sales@iec.ch.

---------------------- Page: 2 ----------------------
IEC TR 62471-4

®


Edition 1.0 2022-09





TECHNICAL



REPORT









colour

inside










Photobiological safety of lamps and lamp systems –

Part 4: Measuring methods



























INTERNATIONAL

ELECTROTECHNICAL


COMMISSION





ICS 29.140.01, 31.260 ISBN 978-2-8322-5734-0




  Warning! Make sure that you obtained this publication from an authorized distributor.


® Registered trademark of the International Electrotechnical Commission

---------------------- Page: 3 ----------------------
– 2 – IEC TR 62471-4:2022 © IEC 2022
CONTENTS
FOREWORD . 5
INTRODUCTION . 7
1 Scope . 8
2 Normative references . 8
3 Terms, definitions and abbreviated terms . 8
3.1 Terms and definitions . 8
3.2 Abbreviated terms . 10
4 Application . 10
4.1 General . 10
4.2 Safety precautions . 10
4.3 Hazard assessment overview . 10
4.4 Selection of hazards . 11
4.5 Assessment levels . 11
4.6 Initial filtering . 12
4.7 Measurement quantities . 12
4.7.1 Emission wavelengths . 12
4.7.2 Irradiance . 13
4.7.3 Radiance . 14
4.7.4 Source size and location . 16
4.7.5 Temporal emission . 18
4.8 Measurement uncertainty . 18
5 Test conditions . 19
5.1 General . 19
5.2 Dark room (level A) . 19
5.3 Environmental conditions (level A) . 19
5.4 Power supply . 19
5.5 Product configuration . 19
5.5.1 General . 19
5.5.2 Warm up . 20
5.5.3 Measurement distance . 20
5.6 Optical alignment . 22
6 Performance characteristics: level A instruments . 22
6.1 General . 22
6.2 Spectral irradiance and radiance . 23
6.2.1 Spectral analysis . 23
6.2.2 Entrance optics . 25
6.2.3 Calibration standards . 26
6.3 Imaging devices . 27
6.4 Temporal emission . 27
6.5 Source size and location . 28
7 Performance characteristics: level B instruments . 28
7.1 General . 28
7.2 Irradiance or radiance . 28
7.2.1 General . 28
7.2.2 UV lines . 29

---------------------- Page: 4 ----------------------
IEC TR 62471-4:2022 © IEC 2022 – 3 –
7.2.3 Narrow band sources . 29
7.2.4 Known spectral distribution . 29
7.2.5 Luminance-based . 30
7.3 Apparent source location and subtense . 31
7.4 Temporal emission . 31
Annex A (informative) Hazard selection . 32
Annex B (informative) Instrumentation description . 33
B.1 Double monochromators . 33
B.2 Single monochromators . 33
B.3 Array spectrometers . 33
B.4 Detectors . 33
B.5 Entrance optics . 34
B.6 Measurement geometries . 36
B.6.1 Irradiance . 36
B.6.2 Radiance . 36
B.7 2D imaging detector . 39
Annex C (informative) Extrapolation of spectral irradiance for thermal radiators . 41
Annex D (informative) Temporal emission measurement . 43
D.1 General . 43
D.2 Pulse duration . 43
D.3 Averaged irradiance and averaged radiance . 44
Annex E (informative) Uncertainty analysis . 47
Annex F (informative) Application examples . 48
F.1 General . 48
F.2 Example 1 – LED flashlight . 48
F.3 Example 2 – Infrared tungsten filament lamp . 49
F.4 Example 3 – Compact fluorescent lamp (CFL) . 51
F.5 Example 4 – LED bulb . 53
Annex G (informative) Stray radiation . 54
Annex H (informative) Report . 56
H.1 General . 56
H.2 Report. 56
Annex I (informative) Relationship between "true" source radiance and spatially
averaged radiance . 58
Bibliography . 62

Figure 1 – Schematic representation of irradiance measurement . 14
Figure 2 – Consideration of filling of FOV . 15
Figure 3 – Example of a direct measurement of radiance using a lens and aperture. 15
Figure 4 – Indirect measurement of radiance . 16
Figure 5 – Example of a rectangular source . 18
Figure 6 – Example of the non-uniform radiance distribution . 18
Figure 7 – Example of the emission profiles . 22
Figure B.1 – Examples of the diffuser optics . 35
Figure B.2 – Schematic representation of irradiance measurement . 36
Figure B.3 – Geometry of radiance measurement with a single thin lens . 37

---------------------- Page: 5 ----------------------
– 4 – IEC TR 62471-4:2022 © IEC 2022
Figure B.4 – Geometry of a general radiance measurement . 38
Figure B.5 – Setup of the aperture stop behind the lens . 38
Figure B.6 – Setup of the aperture stop in front of the lens . 39
Figure B.7 – Example of a 2D imaging detector . 40
Figure D.1 – Example of temporal pulse wave . 44
Figure D.2 – Example of a colour-tunable white LED lamp . 44
Figure D.3 – A single pulse wave . 45
Figure D.4 – Example of a spectrally variable pulse . 46
Figure F.1 – Example of a LED flashlight . 48
Figure F.2 – Example of a radiance profile . 49
Figure F.3 – Spectral radiance distribution . 49
Figure F.4 – Example of an infrared tungsten filament lamp . 50
Figure F.5 – Example of a radiance profile . 50
Figure F.6 – Spectral radiance and irradiance distributions . 51
Figure F.7 – Radiance profile of the lamp . 51
Figure F.8 – Example of a compact fluorescent lamp (CFL) . 51
Figure F.9 – Example of a radiance profile . 52
Figure F.10 – Spectral radiance and irradiance distribution . 52
Figure F.11 – Example of a radiance profile . 53
Figure F.12 – Example of a LED bulb . 53
Figure I.1 – Usual measurement conditions for the determination of (time integrated)
radiance. 59
Figure I.2 – B(λ)-weighted radiance distribution of a phosphor-coated white LED

component . 60


Table 1 – Optical radiation hazards considered by IEC 62471 . 11
Table 2 – Recommended wavelength accuracy . 24
Table 3 – Recommended bandwidths . 24
Table A.1 – Examples of potential risk categories . 32

---------------------- Page: 6 ----------------------
IEC TR 62471-4:2022 © IEC 2022 – 5 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________

PHOTOBIOLOGICAL SAFETY OF LAMPS AND LAMP SYSTEMS –

Part 4: Measuring methods

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 international
co-operation on all questions concerning standardization in the electrical and electronic fields. To this end and
in addition to other activities, IEC publishes International Standards, Technical Specifications, Technical Reports,
Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC Publication(s)”). 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. 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 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 IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence between
any IEC Publication and the corresponding national or regional publication shall be clearly indicated in the latter.
5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
services carried out by independent certification bodies.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
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.
IEC TR 62471-4 has been prepared by IEC technical committee 76: Optical radiation safety and
laser equipment. It is a Technical Report.
The text of this Technical Report is based on the following documents:
Draft Report on voting
76/654/DTR 76/707/RVDTR

Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this Technical Report is English.
A list of all the parts in the IEC 62471 series, under the general title Photobiological safety of
lamps and lamp systems, can be found on the IEC website.

---------------------- Page: 7 ----------------------
– 6 – IEC TR 62471-4:2022 © IEC 2022
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
described in greater detail at www.iec.ch/publications.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under 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.

IMPORTANT – The "colour inside" logo on the cover page of this document indicates that it
contains colours which are considered to be useful for the correct understanding of its
contents. Users should therefore print this document using a colour printer.

---------------------- Page: 8 ----------------------
IEC TR 62471-4:2022 © IEC 2022 – 7 –
INTRODUCTION
Most lamps and lamp systems are safe and do not pose photobiological hazards except under
unusual exposure conditions, whilst a full photobiological safety assessment requires
sophisticated instrumentation and detailed analysis.
In order to provide a framework for the application of detailed measurement only where such is
necessary, this document introduces two measurement approaches. Level A encompasses high
accuracy, laboratory-based techniques whilst level B represents an estimation of the accessible
emission using readily available instrumentation.

---------------------- Page: 9 ----------------------
– 8 – IEC TR 62471-4:2022 © IEC 2022
PHOTOBIOLOGICAL SAFETY OF LAMPS AND LAMP SYSTEMS –

Part 4: Measuring methods



1 Scope
This part of IEC 62471, which is a Technical Report, provides manufacturers, test houses,
safety personnel and others with practical guidance on methods to perform radiometric and
spectroradiometric measurements to determine the level of accessible optical radiation emitted
by lamps and lamp systems in accordance with IEC 62471.
2 Normative references
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.
IEC 62471:2006, Photobiological safety of lamps and lamp systems
3 Terms, definitions and abbreviated terms
3.1 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 62471 and the
following apply.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
• IEC Electropedia: available at http://www.electropedia.org
• ISO Online browsing platform: available at http://www.iso.org/obp
3.1.1
accessible emission
level of radiation determined at a given distance and under measurement conditions defined in
IEC 62471
Note 1 to entry: The accessible emission is compared with the accessible emission limits to determine the
applicable risk group.
3.1.2
angular response
detector output signal as a function of input beam angle
3.1.3
aperture stop
opening that defines the area over which average optical emission is measured
3.1.4
entrance pupil
image of the aperture stop as seen through the object space in an optical system

---------------------- Page: 10 ----------------------
IEC TR 62471-4:2022 © IEC 2022 – 9 –
Note 1 to entry: The entrance pupil defines the acceptance cone in the object space.
Note 2 to entry: If there is no lens in front of the aperture stop, the location and size of the entrance pupil are
identical to those of the aperture stop. Optical elements in front of the aperture stop can either magnify or diminish
the image and modify the location of the entrance pupil with respect to the physical aperture stop.
Note 3 to entry: The entrance pupil is important since the amount of optical radiation collected from the source
depends on this cone angle.
3.1.5
exit pupil
image of the aperture stop as seen through the image space in an optical system
Note 1 to entry: The exit pupil defines the acceptance cone in the image space.
Note 2 to entry: If there is no lens behind the aperture stop, the location and size of the exit pupil are identical to
those of the aperture stop.
Note 3 to entry: The exit pupil is important since the amount of optical radiation falling on the detector depends on
this cone angle.
Note 4 to entry: The cone angle is held constant in the luminance or radiance measurement at different object
distances.
3.1.6
field stop
opening that defines the solid angle over which average optical emission is measured
3.1.7
level A assessment
accurate determination of the accessible emission using sophisticated instruments in laboratory
conditions, performed by a trained operator
3.1.8
level B assessment
estimation of the accessible emission using readily available broadband radiometers or
photometers with minimum training
Note 1 to entry: Level B assessment can be used as a screening method to determine where further detailed
analysis is required without leading to the burden of measuring all sources.
3.1.9
measurement distance
distance between the (apparent) source or the closest point
of human access of the source under test and the entrance pupil
Note 1 to entry: If projection optics generate a virtual image of the emitter, the radiance measurement system
images the plane of this apparent source and not the plane of the closest point of human access.
3.1.10
measurement distance
distance between the (apparent) source or the closest point
of human access of the source under test and the aperture stop
3.1.11
spectral weighting function
function of the relative spectral effectiveness of optical radiation for a specified photobiological
effect in consideration of calculation of a weighted quantity, such as weighted radiance or
weighted irradiance
3.1.12
weighted irradiance
radiometric quantity obtained by multiplying spectral irradiance by a spectral weighting function
and integrating over the limits of the weighting function

---------------------- Page: 11 ----------------------
– 10 – IEC TR 62471-4:2022 © IEC 2022
3.1.13
weighted radiance
radiometric quantity obtained by multiplying spectral radiance by a spectral weighting function
and integrating over the limits of the weighting function
3.2 Abbreviated terms
CCD charge-coupled device
CCT correlated color temperature
CMOS complementary metal–oxide–semiconductor
CW continuous wave
FOV field of view
GLS general lighting service
HID high-intensity discharge
LED light-emitting diode
NMI national metrology institute
PMT photomultiplier tube
4 Application
4.1 General
This document is intended to be used as a reference guide by (but not limited to) manufacturers,
testing laboratories, safety officers and officials of industrial or governmental authorities. It
contains interpretations of IEC 62471 and supplementary information relating to the practical
realization of radiometric measurements of lamps and lamp systems.
The procedures described in this document are adequate to meet the measurement
requirements of IEC 62471 where measurements are deemed to be required. The existence of
other equivalent measurement techniques, yielding results as valid as those described in this
document, is acknowledged.
In many cases, measurement may not be necessary. Compliance with the requirements of
IEC 62471 can be determined from an analysis of reported characteristics of the source and
the design of the product.
4.2 Safety precautions
Optical radiation emitted from a test lamp or lamp system may be potentially hazardous to the
operator's eyes and skin during the measurement. The existence of these hazards
...