IEC TR 60825-9:1999

TECHNICAL IEC
REPORT
TR 60825-9
First edition
1999-10
Safety of laser products –
Part 9:
Compilation of maximum permissible exposure
to incoherent optical radiation
Sécurité des appareils à laser –
Partie 9:
Exposition maximale admissible au rayonnement
lumineux incohérent
Reference number
IEC/TR 60825-9:1999(E)
Numbering
As from 1 January 1997 all IEC publications are issued with a designation in the
60000 series.
Consolidated publications
Consolidated versions of some IEC publications including amendments are
available. For example, edition numbers 1.0, 1.1 and 1.2 refer, respectively, to the
base publication, the base publication incorporating amendment 1 and the base
publication incorporating amendments 1 and 2.
Validity of this publication
The technical content of IEC publications is kept under constant review by the IEC,
thus ensuring that the content reflects current technology.
Information relating to the date of the reconfirmation of the publication is available
in the IEC catalogue.
Information on the subjects under consideration and work in progress undertaken
by the technical committee which has prepared this publication, as well as the list
of publications issued, is to be found at the following IEC sources:
• IEC web site*
•
Catalogue of IEC publications
Published yearly with regular updates
(On-line catalogue)*
• IEC Bulletin
Available both at the IEC web site* and as a printed periodical
Terminology, graphical and letter symbols
For general terminology, readers are referred to IEC 60050: International
Electrotechnical Vocabulary (IEV).
For graphical symbols, and letter symbols and signs approved by the IEC for
general use, readers are referred to publications IEC 60027: Letter symbols to be
used in electrical technology, IEC 60417: Graphical symbols for use on equipment.
Index, survey and compilation of the single sheets and IEC 60617: Graphical symbols
for diagrams.
* See web site address on title page.

TECHNICAL IEC
REPORT
TR 60825-9
First edition
1999-10
Safety of laser products –
Part 9:
Compilation of maximum permissible exposure
to incoherent optical radiation
Sécurité des appareils à laser –
Partie 9:
Exposition maximale admissible au rayonnement
lumineux incohérent
 IEC 1999  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.
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Commission Electrotechnique Internationale
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International Electrotechnical Commission
For price, see current catalogue

– 2 – TR 60825-9 © IEC:1999(E)
CONTENTS
Page
FOREWORD . 3
Clause
1 Scope and object. 4
2 References . 5
3 Definitions. 6
4 Maximum permissible exposure . 16
4.1 General remarks. 16
4.2 Measurement aperture . 17
4.3 Pupil diameter. 18
4.4 Repetitively pulsed, modulated or scanned radiation. 19
4.5 Angular subtense of the source. 21
4.6 Time basis. 23
4.7 Radiance and irradiance . 23
4.8 Maximum permissible exposure of the eye. 24
4.9 Maximum permissible exposure of the skin . 34
4.10 Photometric quantities. 35
5 Measurements. 35
5.1 Measurement conditions. 35
5.2 Measurement methods. 37
Annex A Spectral functions for the Blue-Light-Hazard and the Retinal Thermal Hazard
according to ICNIRP.42
Annex B Ultraviolet exposure limits and spectral weighting functions according to ICNIRP.43
Annex C Relative spectral luminous efficiency according to CIE.44
Annex D Action spectra.45
Annex E Bibliography .49

TR 60825-9 © IEC:1999(E) – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
SAFETY OF LASER PRODUCTS –
Part 9: Compilation of maximum permissible exposure
to incoherent optical radiation
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 technical report may be the subject of
patent rights. The IEC shall not be held responsible for identifying any or all such patent rights.
The main task of IEC technical committees is to prepare International Standards.
However, a technical committee may propose the publication of a technical report when
it has collected data of a different kind from that which is normally published as an
International Standard, for example "state of the art".
Technical reports do not necessarily have to be reviewed until the data they provide are
considered to be no longer valid or useful by the maintenance team.
IEC 60825-9, which is a technical report, has been prepared by IEC technical
committee 76: Optical radiation safety and laser equipment.
The text of this technical report is based on the following documents:
Enquiry draft Report on voting
76/171/CDV 76/204/RVC
Full information on the voting for the approval of this technical report 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 3.
This document which is purely informative is not to be regarded as an International Standard.

– 4 – TR 60825-9 © IEC:1999(E)
SAFETY OF LASER PRODUCTS –
Part 9: Compilation of maximum permissible exposure
to incoherent optical radiation
1 Scope and Object
This Technical Report reconciles current Maximum Permissible Exposure
(MPE) values for the exposure of the human eye and skin to incoherent
optical radiation from artificial sources in the wavelength range from
180 nm to 3000 nm with the ultimate goal of harmonisation. Exposure
limits between 3000 nm and 1 mm wavelength are currently undefined.
These values are based on the best available information from experimental
studies and should be used only as guides in the control of exposure to
radiation from artificial sources and should not be regarded as a precise
line between safe and dangerous levels.
NOTE The values of this report are applicable to most individuals, however, some
individuals may be hypersusceptible or otherwise unusually responsive to optical radiation
because of genetic factors, age, personal habits (smoking, alcohol, or other drugs), medication,
or previous exposures. Such individuals may not be adequately protected from adverse health
effects from exposure to optical radiation at or below the maximum permissible exposure
values of this report. Medical advise should be sought to evaluate the extent to which
additional protection is needed.
These values were mainly developed for exposure to artificial sources.
They may also be used for the evaluation of exposure to sunlight.
The MPE values should not be applicable to exposure of patients to optical
radiation for the purpose of medical treatment.
Maximum permissible exposure values for the exposure to radiation from
laser sources are defined in IEC 60825-1.
NOTE 1 Basic documents of this report were IEC 60825-1 (addressing lasers) and the
IRPA/ICNIRP Guidelines (addressing incoherent sources). ACGIH limits are slightly different
in wavelength ranges and in limit values.
NOTE 2 In spite of the fact that LEDs emit mainly incoherent radiation they are currently
dealt with in IEC 60825-1.
TR 60825-9 © IEC:1999(E) – 5 –
NOTE 3 There are no damage mechanisms which are known to be different for coherent and
incoherent sources. However, in many cases the limit values in IEC 60825-1 are more
conservative than the values in this report. This is especially true in wavelength regions where
no lasers were available when IEC 60825-1 was originally developed.
NOTE 4 Exposures to levels at the MPE values given may be uncomfortable to view or feel
upon the skin.
NOTE 5 In the UV-B and UV-C spectral ranges the MPE values approach the radiant
exposures producing minimally detectable biological changes in the surface corneal cells.
Levels producing harmful effects are 2 to 3 times greater.
1.1 The object of this technical report is to provide guidance for the
protection of persons from incoherent optical radiation in the wavelength
range from 180 nm to 1 mm by indicating safe levels of optical radiation
which are believed to be safe for most individuals in the sense that
exposure at or below these levels will create no adverse effects. Because
only limited knowledge exists about the effects of a long-term exposure,
most MPEs are based on acute effects of the optical radiation exposure
during an eigth hours work day.
1.2
To provide procedures and methods how the level of optical radiation
should be measured and evaluated for the purpose of comparison with the
maximum permissible exposure.
2 Reference documents
IEC 60050(845):1987, International Electrotechnical Vocabulary –
Chapter 845: Lighting
Safety of laser products – Part 1: Equipment
IEC 60825-1:1993,
classification, requirements and user’s guide
*
Amendment 1:1997
ISO 1000:1992, SI units and recommendations for the use of their
multiples and of certain other units
ISO 11145:1994, Optics and optical instruments – Lasers and laser-
related equipment – Vocabulary and symbols
ISO/IEC Guide 51:1997, Safety aspects – Guidelines for their inclusion in
standards
__________
*
There is a consolidated edition 1.1 (1998) that includes IEC 60825-1 (1993) and its amendment 1 (1997).

– 6 – TR 60825-9 © IEC:1999(E)
3 Definitions
For the purposes of this report, the following definitions apply.
Basic definitions are given in ISO 1000:1992, ISO 11145:1994 and
IEC 60050(845):1987. Some of these definitions are repeated, as well as
some definitions from IEC 60825-1 and from ISO/IEC Guide 51.
Departures from the basic documents are intentional.
(In the following, → means “see”)
3.1
angular magnification M
→
angular magnification M of an optical instrument is the ratio of the
visual angle subtended by the object with the instrument (α )
instr
to the visual angle subtended at the eye by the object without the ins-
trument (α )
eye
α
instr
M =
α
eye
NOTE In technical optics the visual angle subtended without optical instruments is usually
based on a comfortable visual distance of 25 cm. In this report the minimum viewing distance
is considered to be not smaller than 10 cm.
3.2
angular subtense
visual angle α subtended by the
apparent source at the eye of an
observer (see figure 1) or at the
point of measurement (see also
IEC  1376/99
maximum angular subtense and
minimum angular subtense)
Figure 1 – The definition of the angular
subtense of the apparent source
α
Symbol: α
SI unit: radian
3.3
aperture, aperture stop
aperture stop is an opening serving to define the area over which radiation
is measured (see also measurement apertur
...