IEC TR 60825-3:2022
(Main)Safety of laser products - Part 3: Guidance for laser displays and shows
Safety of laser products - Part 3: Guidance for laser displays and shows
IEC TR 60825-3:2022 gives guidance on the planning and design, set-up and conduct of laser displays and shows that make use of high power lasers emitting output between 380 nm and 780 nm.
This document is a code of practice for the design, installation, operation and evaluation of the safety of laser light shows and displays, and the equipment employed in their production. This document is also intended for persons who modify laser display installations or equipment.
The laser power needed to produce visually effective theatrical or artistic displays in large spaces such as theatres, arenas, or architectural sites is great enough to pose a severe accidental exposure hazard, even when personal exposure is very brief. For this reason, IEC TR 60825-14 states that only laser products that are Class 1, Class 2 or visible-beam Class 3R should be used for demonstration, display or entertainment purposes in unsupervised areas. Only under carefully controlled conditions and under the control of a trained experienced operator can laser products of higher classes be used for visual entertainment.
This document expands upon the principles considered in IEC TR 60825-14, providing specific technical guidance appropriate for the safe use of laser products used for the purposes of visual entertainment.
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IEC TR 60825-3 ®
Edition 3.0 2022-07
TECHNICAL
REPORT
colour
inside
Safety of laser products –
Part 3: Guidance for laser displays and shows
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IEC TR 60825-3 ®
Edition 3.0 2022-07
TECHNICAL
REPORT
colour
inside
Safety of laser products –
Part 3: Guidance for laser displays and shows
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 31.260 ISBN 978-2-8322-3925-4
– 2 – IEC TR 60825-3:2022 © IEC 2022
CONTENTS
FOREWORD . 4
INTRODUCTION . 6
1 Scope . 7
2 Normative references . 8
3 Terms and definitions . 8
4 Exposure hazards and biological effects . 15
4.1 Laser projector classification and hazards. 15
4.2 Biological effects on the eye . 15
4.3 Biological effects on skin . 16
5 Zone limits and maximum permissible exposures (MPE) for laser effects . 16
5.1 Compliance with maximum permissible exposure (MPE) . 16
5.2 Spectator zone MPE . 17
5.3 Performer zone (controlled location) MPE . 17
5.4 At-risk ancillary personnel MPE . 17
6 Safety criteria for equipment and installations . 18
7 Responsibilities of designers, installers, operators and performers . 22
7.1 Training . 22
7.2 Planning by designers, installers and operators . 22
7.3 Set-up and alignment . 24
7.4 Operation . 25
7.5 Display safety record (DSR) . 26
7.6 Contingency planning. 27
7.6.1 General . 27
7.6.2 Dealing with an actual eye injury . 27
7.6.3 Dealing with an actual skin injury . 27
7.6.4 Dealing with a suspected eye injury . 27
7.7 Incident reporting and accident investigation . 27
8 Laser display risk management . 28
8.1 Laser effect exposure risk . 28
8.2 Laser display risk factors and controls . 28
9 Exposure assessment . 30
9.1 Recommendation . 30
9.2 Guidance . 30
9.3 Difficulties . 30
9.4 Evaluation considerations . 32
9.5 Measurement considerations . 32
9.6 Scan-fail safeguard . 33
10 Special considerations . 35
10.1 Holographic displays . 35
10.2 Ultraviolet and blue-light laser beams . 36
Bibliography . 37
Figure 1 – Human eye . 16
Figure 2 – Audience/spectator separation auditorium scenario with operator in control . 19
Figure 3 – Audience/spectator separation nightclub scenario with operator in control . 20
Figure 4 – Audience/spectator separation near a balcony with operator in control . 21
Figure 5 – Audience/spectator separation from unattended beams. 22
Figure 6 – Laser hazard warning signage . 29
Figure 7 – Effective pulse duration . 31
Figure 8 – Apparent pulse train at the measurement device highlighting the differences
between measurement results for average power as measured by a standard power
meter and peak power as measured by a specialized meter . 31
Figure 9 – Time for a scan-fail safeguard to be effective after having been triggered . 34
Table 1 – Summary of MPE selection criteria . 18
Table 2 – Laser effect category . 28
Table 3 – Ocular MPE and equivalent power through a 7 mm diameter aperture . 35
– 4 – IEC TR 60825-3:2022 © IEC 2022
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
SAFETY OF LASER PRODUCTS –
Part 3: Guidance for laser displays and shows
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
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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.
IEC TR 60825-3 has been prepared by IEC technical committee 76: Optical radiation safety and
laser equipment. It is a Technical Report.
This third edition cancels and replaces the second edition published in 2008. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) updates and provides additional terms and definitions relating to laser displays and shows;
b) adds information on exposure hazards and biological effects;
c) updates and provides additional safety criteria from a technical perspective of equipment
and installations;
d) updates and provides additional safety management guidance for designers, installers,
operators and performers;
e) adds guidance on identifying and managing laser display risk, including laser effect
exposure risk categories to aid management;
f) adds guidance on the management of incidents and accidents;
g) adds guidance on exposure assessment, highlighting evaluation and measurement
difficulties, and providing guidance on undertaking measurements.
The text of this Technical Report is based on the following documents:
Draft Report on voting
76/662/DTR 76/692/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 parts in the IEC 60825 series, published under the general title Safety of laser
products, can be found on the IEC website.
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/standardsdev/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 publication 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.
– 6 – IEC TR 60825-3:2022 © IEC 2022
INTRODUCTION
Laser products are used to create visual lighting effects for the purposes of entertainment.
IEC 60825-1 considers the hazard classification and engineering requirements of laser products,
while IEC TR 60825-14 provides general user guidance for the safe use of laser products.
The laser power needed to produce visually effective theatrical or artistic displays in large
spaces such as theatres, arenas, or architectural sites is great enough to pose a severe
accidental exposure hazard, even when personal exposure is very brief. For this reason,
IEC TR 60825-14 states that only laser products that are Class 1, Class 2 or visible-beam
Class 3R should be used for demonstration, display or entertainment purposes in unsupervised
areas. Only under carefully controlled conditions and under the control of a trained experienced
operator can laser products of higher classes be used for visual entertainment.
This document expands upon the principles considered in IEC TR 60825-14, providing specific
technical guidance appropriate for the safe use of laser products used for the purposes of visual
entertainment.
SAFETY OF LASER PRODUCTS –
Part 3: Guidance for laser displays and shows
1 Scope
This part of IEC 60825, which is a Technical Report, gives guidance on the planning and design,
set-up and conduct of laser displays and shows that make use of high power lasers emitting
output between 380 nm and 780 nm.
This document does not include the display or demonstration of scientific, medical or industrial
laser products that can be used in an exhibition environment for example. However, several of
the principles in this document could be relevant. This document provides recommendations for
safety for those laser displays or demonstrations that are shows, artistic displays, advertising
or light sculptures, or museum pieces used to demonstrate optical principles, etc.
Laser products available for use in a domestic environment or for use by people who cannot be
expected to have received a suitable level of training are typically limited to Class 1, Class 2 or
visible-beam Class 3R. Therefore, the use of such equipment is outside the scope of this
document.
Image projectors that were assigned a Risk Group in accordance with IEC 62471-5 [1] or laser
illuminated luminaires employing lamps meeting the criteria of 4.4 of IEC 60825-1:2014, are not
within the scope of this document.
This document contains safety criteria for the protection of the public or persons in the vicinity
of laser displays in the course of their employment.
This document is intended to be used by those who:
– design, manufacture, assemble, install or operate laser products that are Class 4, Class 3B,
or non-visible beam Class 3R for display and entertainment purposes;
– operate arenas, theatres, music festivals, TV studios, planetaria, discotheques or other
places where such laser products are installed and operated; or
– are responsible for reviewing the safety of such equipment, installations or displays.
This document is a code of practice for the design, installation, operation and evaluation of the
safety of laser light shows and displays, and the equipment employed in their production. This
document is also intended for persons who modify laser display installations or equipment.
In some countries, there are specific requirements, such as government permissions or
notifications of shows, or prohibitions, such as against laser scanning of spectators.
___________
Numbers in square brackets refer to the Bibliography.
– 8 – IEC TR 60825-3:2022 © IEC 2022
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.
lEC 60825-1, Safety of laser products – Part 1: Equipment classification and requirements
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 60825-1 and the
following apply.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
• ISO Online browsing platform: available at https://www.iso.org/obp
• IEC Electropedia: available at http://www.electropedia.org/
3.1
aversion response
reflex avoidance action (closing the eyes and turning away) when a person is suddenly exposed
to a bright light source
Note 1 to entry: Through this action the duration of an accidental exposure to a visible beam is normally considered
to be 0,25 s. However, alcohol or narcotic substances can have a detrimental effect on the aversion response, and
even without such influences spectators can be inclined to override this response to continue viewing the
performance.
3.2
Amsler grid
visual tool used to detect vision problems resulting from damage to the macula, the part of the
eye used to detect central vision detail
3.3
ancillary personnel
backstage workers, ushers, security guards, technicians, food and beverage suppliers, etc.,
who are working at the venue or facility at which a laser display or show is being set up or
presented, but who are not directly involved with the laser display or show
Note 1 to entry: Ancillary personnel can have access to areas from which spectators are excluded.
3.4
aperture
opening in the protective housing of a laser product through which laser radiation is emitted,
thereby allowing human access to such radiation
Note 1 to entry: The aperture is of limited size so that only the intended laser effect can emit from laser projector.
3.5
audience illumination
laser lighting effect that is intentionally accessible, allowing direct illumination of the area
occupied by spectators
Note 1 to entry: Common techniques used to produce this type of effect include:
– direct scanning of the laser beam, using electromechanical devices, such as galvanometers, to deflect the beam
position, typically, in a dynamic fashion;
– diffraction effect (3.12) using diffractive optic elements;
– high inertia scanning effects, such as rotating polygon mirror and mirror ball beam deflection;
– solid-state beam deflection techniques, using devices such as acousto-optic modulators and
microelectromechanical systems (MEMS).
Note 2 to entry: The varying characteristics associated with each different effect type influence the degree of hazard
present and how it can be managed. Factors include differing maximum peak irradiance, exposure duration potential,
time available for effective scan-fail detection and mitigation.
3.6
barrier
device to separate spectators from zones where potentially hazardous laser radiation exists
Note 1 to entry: It is important that barriers are robust and not capable of being readily displaced or traversed by
spectators.
Note 2 to entry: A barrier can be a wall, a fence, stage front, etc.
Note 3 to entry: Less substantial barriers such as stanchions or ropes can be considered to be adequate barriers if
the entire protected area is visible to and monitored by the laser operator or other safety and security personnel
during the laser display.
3.7
bounce mirror
mirror located remotely from the laser projector used to target a static beam
Note 1 to entry: Bounce mirrors are often used in multiples to create the appearance of multiple networks of beams.
3.8
control signal
means by which the laser projector is controlled by the laser operator or a pre-programmed
control system
Note 1 to entry: The resilience of the control signal to interference from other of sources within the environment is
important. For this reason, the use of wireless control signals is discouraged.
3.9
controlled location
area inaccessible except to authorized, trained persons that have received sufficient training or
instruction about laser safety
Note 1 to entry: Controlled locations typically include the performer zone, but can also encompass restricted areas
where laser beams are accessible. They also include restricted areas in which ancillary personnel can be present or
to which ancillary personnel have access.
3.10
designer
person who determines the visual effects to be produced, the planning of the projections, and
the locations of the equipment to be used
Note 1 to entry: The designer can, in addition, act as installer or operator and be considered to be a manufacturer
(3.27) or supplier.
– 10 – IEC TR 60825-3:2022 © IEC 2022
3.11
display safety record
DSR
written record of safety information relevant to a specific laser display or show
3.12
diffraction effect
type of laser effect produced by the interaction of a laser beam with a diffractive optical element
(DOE) or diffraction grating
Note 1 to entry: The laser beam interaction causes the original beam to split and form a geometric pattern, such as
a grid or line of beams. The appearance of the emergent pattern is predominantly determined by the characteristics
of the DOE. The substrate containing the DOE is usually rotated during use to create the appearance of movement.
Note 2 to entry: Diffraction effects can be produced either by using a reflective substrate which behaves like a
mirror, with pattern being formed as a reflection, or by using a transmissive substrate, where the beam passes
through the DOE and the pattern is formed at the beam exit. Reflective diffraction effects are often used in similar
fashion to bounce mirrors. Transmissive laser effects are typically created within the laser projector itself, with the
DOE being moved into the path of a stationary laser beam or scanning output.
Note 3 to entry: Diffraction effects normally contain a zero order (3.46) beam.
3.13
effective pulse duration
time taken for a moving beam to traverse the 7 mm limiting aperture of the eye
Note 1 to entry: Often used for evaluating the exposure created by a scan pattern or moving effect, where in most
instances the exposure experienced by a person is independent of the, often CW, laser source output characteristics.
Note 2 to entry: This duration can be estimated by considering the leading and trailing edges of a top-hat scanning
beam profile passing over the pupil.
3.14
emergency stop control
e-stop
reliable method of terminating the output of a laser projector system
Note 1 to entry: It is important the emergency stop control functions independently of the laser system's control
signal, which can become unstable in the case of a fault occurring. This is particularly important as common lighting
and laser effect control protocols generally have no or little fault tolerance.
3.15
engineering control
mechanical or electrical safety measure intended to continuously protect people from exposure
to a hazard, usually characterized by being in addition to the system and not relying on specific
human action to be effective
Note 1 to entry: Common examples include key operated controls, warning indicators, and physical masking.
3.16
errant laser effect
laser beam that deviates from a defined or intended beam path
Note 1 to entry: Such beams include unwanted reflections in the projection area, or movement of the laser projector
or remote optical target causing laser beams to appear outside of the intended projection area.
3.17
inaccessible location
area that can be accessed only using specialized equipment, additional equipment, or both
Note 1 to entry: Access equipment typically includes mobile lifts, ladders, ropes, scaffolding, etc.
3.18
intentionally accessible effect
laser effect category that by design and implementation permits beams to be readily accessible
to persons
Note 1 to entry: An example of this category of effect is audience illumination, but could equally apply to others,
such as performers and ancillary personnel illumination. In each instance it is important that any exposure is not in
excess of the applicable MPE.
3.19
installer
person who places the equipment in the designated locations and participates in the adjustment
and alignment to produce the desired effects
Note 1 to entry: An installer may also be a manufacturer (3.27) or supplier if the installation activities result in
modification of the display laser product effects.
3.20
laser classification
indication of the potential risk of harm of a laser, where the higher the class number indicates
a greater hazard from exposure to the laser beam emitted by the product
Note 1 to entry: IEC 60825-1 defines eight distinct laser hazard classes that identify the general risk posed by a
laser product and mandates the required safety features that the laser product is to have based on its accessible
laser radiation.
Note 2 to entry: The majority of laser projectors used to create laser effects are Class 3B and Class 4 laser products
that emit beam(s) posing a risk to eyes and skin, and can act as a source of fire ignition.
3.21
laser display or show
activity where at least one laser beam is projected onto a surface or made visible in the air, for
purposes such as entertainment or art, and usually intended to be viewed by a non-specialist
audience
Note 1 to entry: This definition includes demonstrations, such as in museums or educational establishments, and
laser shows such as in planetariums, nightclubs, concert and entertainment venues, art installations and advertising
projections.
3.22
laser effect
all electromagnetic radiation emitted by a laser product between 380 nm and 780 nm which is
produced as a result of controlled stimulated emission
Note 1 to entry: A laser effect can appear stationary or moving using optical components to manipulate the
characteristics of the laser beam.
3.23
laser effect category
identification of the laser effect application based on the intended accessibility to the laser
beam(s)
Note 1 to entry: Laser effects are considered to belong to one of three categories based on the potential for direct
exposure, which helps to identify the specific types of controls necessary to safely manage use of the laser effect.
3.24
laser projector
laser used, alone or with beam-manipulating components, to produce laser displays or show
effects
Note 1 to entry: Laser projectors are considered laser products subject to the applicable provisions of IEC 60825‑1,
within the scope of this document.
– 12 – IEC TR 60825-3:2022 © IEC 2022
3.25
laser protection adviser
LPA
person who is usually independent of the laser installation and its day-to-day operation, but
who is suitably qualified in understanding laser hazard prevention strategies, is able to
understand and assess safety matters in relation to laser display installations, evaluate and
quantify exposure levels, and is familiar with the appropriate legal responsibilities and
requirements
3.26
laser safety officer
LSO
person who is knowledgeable in the evaluation and control of laser hazards and has
responsibility for oversight of the control of laser hazards
Note 1 to entry: The role of the laser safety officer can vary widely, depending on the safety management needs of
the organization in which he or she is employed. It is often not necessary for the laser safety officer to be able to
perform quantitative hazard analyses.
Note 2 to entry: Organizations using Class 3B and Class 4 laser equipment normally appoint an internal laser safety
officer to take administrative responsibility on behalf of the employer for overseeing laser safety.
Note 3 to entry: The duties of the laser safety officer are usually documented and are those necessary to ensure
the continuing safe use of lasers within the organization concerned. They are likely to include as a minimum:
a) being aware of and, if appropriate, maintaining records of, all potentially-hazardous laser products (including the
classifications, specifications, and purposes of the laser products; the locations of the laser products; and any
special requirements or restrictions relating to their uses);
b) responsibility for monitoring compliance with the organization's procedures for ensuring safe laser use, for
maintaining appropriate written records, and for taking immediate and appropriate action in respect of any non-
compliance or apparent inadequacy in such procedures.
3.27
manufacturer
person (or persons) who constructs, assembles or produces one or more laser projectors, or
the displays or shows (physical set-up of equipment) which use laser projectors
Note 1 to entry: This applies whether or not the manufacture is done for profit.
Note 2 to entry: The equipment used to produce a laser display or show is considered to be a laser product.
3.28
mask
baffle
physical mask
physical mask able to stop laser beams from travelling in unwanted directions
Note 1 to entry: The mask is generally a sheet or panel made of durable material able to withstand, without
penetration, the maximum anticipated level of laser radiation. It is important the mask does not slip or move relative
to the impinging laser beam.
Note 2 to entry: Beams controlled by electronics or computers will often employ "software masks" so the beam is
prevented from emitting, or operating at maximum output, in defined areas within the potential projection area. If
software masks are used then it is important that full consideration of the failure modes of the scanning system and
the consequences of failure be considered. In some situations, more formal assessments, such as described in the
IEC 61508 series [2], will be needed.
Note 3 to entry: It is important the performance of masks, whether physical or software, be evaluated under
reasonably foreseeable single fault conditions.
3.29
modifier
person who changes the performance, layout, or effects of a laser display or show, or who
makes changes in the components of the system that impact the safety characteristics
Note 1 to entry: A modifier is also considered to have the same responsibilities as a manufacturer (3.27), supplier
or designer (3.10).
3.30
non-accessible effect
laser effect category that by design and implementation renders no beams as being accessible
to any person
Note 1 to entry: The laser projector and beam trajectory are located in an inaccessible location, normally supported
by the use of engineering controls to prevent errant laser effects.
3.31
operator
person who has direct operational control of the laser or projection system(s)
Note 1 to entry: It is important operators be trained on the hazards involved with the lasers being used and are
expected to comply with the safety instructions that are provided by the manufacturer (3.27). An operator can also
be designated as the laser safety officer for the laser display or show.
3.32
performer
person who entertains the public during a show
Note 1 to entry: Performers can be dancers, singers or musicians, etc.
Note 2 to entry: Performers are expected to have been instructed on the hazards involved with the lasers being
used and can often be reasonably expected to comply with the safety instructions that are provided.
3.33
performer zone
area in which only performers may be present and within which laser radiation may exceed the
spectator MPE
Note 1 to entry: The performer zone is usually a controlled location situated on a stage.
3.34
potentially accessible effect
laser effect that by implementation is not designed to be intentionally accessible, but within the
designated controlled location beams in excess of the applicable MPE could be accessed if
there are not sufficient controls in place, or controls are ignored by persons present within the
controlled location
3.35
projection area
area in which the laser beam or effect is designed to be present during normal intended
operation of the laser projector
Note 1 to entry: The projection area includes the space the beam or beams travel through, and the surfaces where
they terminate.
3.36
responsible person
person, working in the field, who takes charge of the laser installation, the operation of the laser
effects or both, and in doing so is responsible for ensuring such work is carried out in a way
that minimizes exposure risk, and does not deviate from the parameters agreed with the laser
safety officer, the laser protection adviser or both
Note 1 to entry: It is important the responsible person have received basic training and instruction on how to carry
out their task in a safe manner, be able to identify and avoid hazardous situations arising, and be able to terminate
laser output where necessary to prevent harmful exposure.
Note 2 to entry: In some situations, the same responsible person can undertake the laser effect design, installation,
and operation roles for the provision of the display. There are circumstances however where different persons need
to adopt the role of the responsible person. For example, where a laser installation has been installed into a venue,
and operation is handed over to the venue's technicians, different people adopt the role. There can be a hierarchy
of responsible persons at an installation where, for example, a venue's safety manager adopts a senior role, ensuring
that its technicians and operators are aware of and fulfil their obligations during laser effects operation.
– 14 – IEC TR 60825-3:2022 © IEC 2022
3.37
restricted location
area that is inaccessible to spectators and general public but can be accessible to other
observers or untrained personnel
Note 1 to entry: Employees of the venue, and ancillary personnel are likely to be considered untrained personnel.
3.38
scan pattern
effect produced when a laser beam is scanned, often using a pair of mirrors mounted on
galvanometers
3.39
scan-fail safeguard
engineering feature of a laser projector that is intended to prevent access to laser effects in
excess of the relevant MPE
Note 1 to entry: This feature is often incorporated into the scanning element of a laser projector to prevent the
emission of a stationary beam, or beams that move too slowly. All scan-fail safeguards have a finite response time.
Note 2 to entry: Scan-fail safeguards vary in complexity. Rudimentary systems can prevent the output of a stationary
beam, monitoring the derivative of the x- and y-axis galvanometer velocity feedback signals in a closed loop scanning
system. More sophisticated systems monitor additional characteristics including the movement and repetition of the
scan pattern, and sample the beam output, to actively limit the beam emitted from the laser projector where
necessary.
Note 3 to entry: The presence of a scan-fail safeguard does not make application of the laser projector for audience
illumination inherently safe. It is important the user fully understands the parameters and failure modes the scan-fail
safeguard is able to act upon, and the implications of these characteristics. Safety of the resultant exposure is
additionally dependent on other factors such as the laser beam characteristics – e.g. the radiant power, beam
divergence – and proximity to the spectators viewing the display.
Note 4 to entry: It is critical the reliability of the scan-fail safeguard takes into consideration all possible failure
modes of the scan-fail safeguard and correct operation be verified at regular intervals.
Note 5 to entry: In some situations, more formal assessments, as described in the IEC 61508 series [2], will be
needed.
3.40
scan-fail safeguard response time
total time taken for a scan-fail safeguard to detect a fault, trigger a corrective action, and for
the corrective action to become effective
Note 1 to entry: The scan-fail safeguard response time to correct a hazardous emission is inevitably longer than
just the fault detection time alone. It is important to exercise caution when considering durations quoted by laser
projector manufacturers (3.27), who typically state the fault detection time only.
3.41
spectator
person who is present at the laser display or show who, by location or proximity, could
potentially be exposed to hazardous direct or reflected laser beams (in the absence of any
safety features, or in a worst-case situation) and who is the intended audience for the laser-
created effects
Note 1 to entry: This does not include the laser display operator and their staff, or performers, but could include
bystanders and others that are not part of the performance and are untrained.
Note 2 to entry: Spectators can neither be expected to have been briefed on the safety procedures regarding the
lasers in use, nor be expected to comply with safety instructions.
3.42
spectator MPE
maximum level of ambient laser radiation that may exist in a spectator zone
3.43
spectator zone
area in which spectators may be present and within which laser radiation is restricted to the
spectator MPE
Note 1 to entry: Such areas are considered to be an unrestricted location (3.44).
3.44
unrestricted location
area where the occupancy and activity of the occupants is not subject to control or supervision
for the protection of laser related hazards
Note 1 to entry: Such areas typically include the spectator zone.
3.45
x-y gain control
effect size
control to set the maximum scanning extent of each axis in an x-y based laser projector system
Note 1 to entry: This is often implemented as a control at the laser projector that reduces the control signal to the
scanner driver amplifiers, or a numeric value set as a limit in software.
3.46
zero order
0-order
occupying the position of the incident beam axis for a transmissive diffraction element,
or the reflection from the incident beam for a reflective diffraction element
Note 1 to entry: Emergent beams from a diffraction effect form multiple “orders” in the pattern.
Note 2 to entry: The zero order beam normally comprises the most energy of the emergent orders from a diffraction
effect.
Note 3 to entry: The emergent higher order beams rotate about the zero order beam, which remains stationary
when the diffractive optical element is rotated.
Note 4 to entry: It is important that the zero order beam itself not be directed into accessible areas, as the beam
remains stationary, even with the effect rotating. Additionally, if the diffracting medium degrades, or falls out of the
beam path, it makes a solid beam accessible, presenting a risk to persons in the area where the beam terminates.
4 Exposure hazards and biological effects
4.1 Laser projector classification and hazards
Most laser displays use Class 3B or Class 4 laser products in open spaces to produce laser
effects that can be seen by spectators. Beams emitted by Class 3B lasers are capable of
causing an eye injury if direct exposure to the beam is, even briefly, allowed to occur. Beams
emitted by Class 4 lasers present a risk of eye injury from both direct beam exposure and in
some cases, viewing diffuse reflections. Class 4 lasers may also burn skin, and act as fire
ignition source. The beams from lasers should not be directed at people unless extreme caution
is exercised to ensure the safe exposure. Video projectors and cameras may be damaged
through direct exposure.
NOTE The definitions for laser classifications and MPE are provided in IEC 60825-1 and IEC TR 60825-14.
4.2 Biological effects on the eye
Visible beam exposure at sub-injury (below MPE) level can lead to temporary effects such as
flash blindness, which can interfere with a person's ability to complete a task. Exposure to a
laser beam in excess of the MPE can result in one or a combination
...
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