NTNU
Safe use of lasers
HSE
Prepared by
The HSE
section
Approved by
The Rector
Number
Date
HMSR-34
01.12.2006
Page
1 of 6
Replaces
01.12.2006
1. Objective
Ensuring adequate radiation protection in relation to the acquisition, use, handling
and disposal of lasers, with an emphasis on class 3B and class 4 lasers.
2. Scope
Applies to all units which acquire, use, handle and dispose of classes 1M, 2M, 3R,
3B and class 4 lasers at NTNU. This set of guidelines, in combination with the
Radiation Protection Regulations [strålevernforskriften] and the norm NEK EN 608251, govern the radiation protection for lasers at NTNU.
3. Responsibilities and authority
The line manager is responsible for ensuring that adequate radiation protection is in
place for the unit’s lasers, and for ensuring that someone responsible for the
apparatus is appointed for each laser in classes 3B or 4 owned by the unit. The line
manager must ensure that users are given training in radiation protection related to
the sources found at the unit.
4. Definitions and abbreviations
Laser: Optical source of radiation where the radiation is amplified by stimulated
emission. The laser beam normally takes the shape of a thin line extending into the
room. It is characterised by its normally strongly concentrated nature: its diffusion
angle and the diameter of its beam are very small and it is monochromatic. In this set
of guidelines, ”laser” describes isolated lasers as well as laser systems.
Laser class: Lasers are classified according to the risk they represent in terms of
potential harm to the eyes, and for the strongest lasers also in terms of potential skin
injury. Class 1 is the lowest (safe) and class 4 the highest (the most dangerous) class
in the system, see HMSRV3401E.
LASER: Light Amplification by Stimulated Emission of Radiation
MPE: Maximum Permissible Exposure – safe exposure limits for radiation of eyes
and skin
5. Safe use of lasers
5.1 Acquisition of class 3B or class 4 lasers
Before acquisition of class 3B or class 4 lasers, the following must be done/clarified:
 Submit report to the NRPA [Statens strålevern] for class 4 lasers: the NRPA must
receive a report on a separate form. A copy must be submitted to the central
radiation protection officer at the HSE Section.
 Ownership (in cases of joint acquisition by several units)
 The owner must make a risk assessment before installation and use
 In cases of joint acquisition/use (e.g. with SINTEF), who is responsible for HSE?
 Who will be responsible for the apparatus?
 Who is the local radiation protection coordinator?
 Is any particular competence required in order to use the apparatus? Does this
competence exist at the unit?
NTNU
Safe use of lasers
HSE
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Prepared by
The HSE
section
Approved by
The Rector
Number
Date
HMSR-34
01.12.2006
Page
2 of 6
Replaces
01.12.2006
Who will take care of preventative maintenance? Service agreements?
Is any particular protection/screening in relation to neighbouring rooms/activities?
Ensure that the system is supplied with Norwegian labelling.
Contact the Technical Division if particular cleaning routines or ventilation
requirements apply, or if changes to buildings are required.
When acquiring lasers costing more than N.kr. 200 000 (VAT excluded), the
Purchasing Section [Innkjøp] must be contacted. Please find their checklist here.
Consider also whether safety devices and personal protective equipment (e.g.
laser goggles) needed for the new equipment need to be bought
Class 4 lasers must not be acquired, used or handled before the unit has received
confirmation from the NRPA that the report has been received by them.
5.2 Installation and use of lasers – assessment of risk factors
Before class 3B and class 4 lasers are installed and used, an assessment must be
made of the safety of the system in relation to its users, other personnel in the
vicinity, the buildings, the environment (e.g. if dangerous gases are used) etc. The
assessment should be conducted in consultation with the local radiation protection
coordinator – please use the checklist (HMSRV3402E).
For class 1M, class 2M and class 3R lasers it must be ascertained whether the same
risk assessment as above is required, since these may involve a considerable risk of
potential harm in certain contexts/conditions.
5.3 Organisation of the users
5.3.1 Person responsible for the apparatus
Every class 3B or class 4 laser must have someone who is responsible for the
apparatus, and preferably also a substitute. The person responsible for the apparatus
has a general responsibility for the apparatus, for radiation protection related to the
particular laser, and for providing its users with knowledge and training in how to
handle it.
In terms of class 4 lasers the person responsible for the apparatus must evaluate
whether potential users have sufficient competence to function as unsupervised
(independent) users of the relevant sources and provide documentation for this in the
form ”Approval of unsupervised user of class 4 lasers at NTNU” (HMSRV3403B).
In terms of unsupervised users of class 3B lasers the person in charge of the
apparatus must ascertain that these have sufficient competence. Unlike for class 4
lasers, however, there is no requirement to register this information.
5.3.2 Unsupervised user of class 4 lasers
Unsupervised users of class 4 lasers must have sufficient competence to make
independent evaluations in terms of safe use of the laser source. Sufficient
competence implies apparatus-specific knowledge about starting-up procedures,
NTNU
Safe use of lasers
HSE
Prepared by
The HSE
section
Approved by
The Rector
Number
Date
HMSR-34
01.12.2006
Page
3 of 6
Replaces
01.12.2006
instrument settings, safety devices, shutting-down, emergency procedures if such
apply, the contents of the information binder, any completed measuring of radiation,
etc.
5.3.3 Supervised use of class 3R, class 3B and class 4 lasers
The person responsible for experiments/demonstrations must ensure that everyone
present has understood the hazards associated with the laser and is wearing the
required protective equipment. During demonstrations for special groups, such as
children, following up safety measure is particularly important.
5.4 Safety and technical requirements
5.4.1 Technical measures designed to prevent exposure
Units using class 3B and class 4 lasers must implement and document technical
measures designed to prevent that anyone is exposed to radiation that exceeds the
safe exposure limits (MPE). The checklist in appendix 2 is designed for this use.
Rooms or areas with class 3B and class 4 lasers must have restricted access to
prevent unauthorised persons from entering areas where they might be exposed to
radiation exceeding the limits for safe exposure (MPE).
Rooms for storing sources that are not in use must be locked up. Exceptions may be
made for periods during which the room is normally under constant surveillance.
5.4.2 Labelling and signposting
A room-card and a warning sign must be posted beside all doors leading to rooms
where class 3B and class 4 lasers are used:

The room-card must provide concise information in terms adapted to
outsiders/non-experts (cleaning staff, fire fighters etc.) about the dangers
associated with the room, and the required precautions. Specific risk
factors/dangerous conditions related to the laser must be specified on the roomcard.

The warning sign must contain the triangular symbol providing warning about
laser radiation, and preferably also basic information about the radiation and
required safety equipment (goggles etc.).
Lasers must be labelled in accordance with the current version of Norwegian
standard NEK EN 60825-1:
 Exit radiation of the laser.
 Classification.
 Warning against opening the cover of the beam exit point.
 Warning against invisible radiation, if such is present.
 Label on the laser providing product information.
The labelling must be in Norwegian (equivalent information may be provided in
additional languages as needed).
NTNU
Safe use of lasers
HSE
Prepared by
The HSE
section
Approved by
The Rector
Number
Date
HMSR-34
01.12.2006
Page
4 of 6
Replaces
01.12.2006
5.4.3 Protective equipment
Adapted personal protective equipment must be available to anyone using or
observing lasers in order to prevent that anyone is exposed to laser radiation
exceeding the limits for safe exposure (MPE):
 Laser goggles must be made available to anyone present during the operation of
lasers potentially harmful for the eyesight. Lenses and frames must be adapted to
the particular laser radiation in question and to the needs of the wearers. The
laser goggles must be certified and labelled in a way that makes it clear which
laser they are to be used for.
 If required, there must be enough laser-specific goggles for laser ray tracing etc.
These must provide sufficient weakening for the radiation to correspond to laser
class 2.
 Adequate safety equipment for preventing skin injury must be available if there is
a potential danger of harmful exposure. Face-shields, fireproof clothing and
gloves are examples of such safety equipment, which is particularly appropriate in
the context of UV lasers and powerful IR lasers (CO2).

The equipment required to prevent other persons and enterprises in the vicinity
from potential exposure to harmful laser radiation must be available.
5.5 Emergency preparedness
The unit must prepare a local emergency plan after assessing the risks associated
with its activities and equipment. As a minimum, the emergency plan should include:
 Internal and external procedures for notification/sounding of alarm
 The distribution of responsibilities
 Planned procedures for the handling of specific situations
 Procedures for identifying the extent of an accident/incident
 A description of relevant emergency equipment and where this is found
 Procedures for following up personnel and others involved in the episode
The local emergency plan must be coordinated with the Central emergency plan for
accidents involving sources of radiation at NTNU. It is important that people in the
unit are familiarised with the emergency plan.
5.5.1 Informing other personnel and others in the vicinity
Other persons performing work in the unit, but who are not connected to its academic
activities (cleaners, craftsmen etc.), must be informed about the most important
properties and dangers connected to the laser, cleaning procedures, the significance
of warning signs and warning lights, contact information etc.
5.6 Documentation
5.6.1 Inventory of sources
All class 3B and class 4 lasers must be registered with the local and central radiation
protection coordinators. New acquisitions, as well as relocation and disposal of
apparatuses must be registered.
NTNU
Safe use of lasers
HSE
Prepared by
The HSE
section
Approved by
The Rector
Number
Date
HMSR-34
01.12.2006
Page
5 of 6
Replaces
01.12.2006
5.6.2 Log
Each laser must have a log into which is entered the names of users, date,
alternatively also duration, type of work, maintenance and other information that must
be entered into a log. Maintenance and significant changes to the instrument set-up
must also be entered into the log. The log/s must be kept beside the apparatus. A
back-up copy must be made annually by the person responsible for the apparatus.
This back-up copy must be stored in the unit for a minimum period of 10 years.
5.6.3 Information binder
Each laser apparatus must have an information binder (HMSRV3404B) in which as a
minimum requirement must be included the following:
• General information
- Name of the person responsible for the apparatus and his/her substitute, and
of the local radiation protection coordinator/s
- Vital data about the apparatus
- Apparatus-specific documentation
- References to (or copies of) data sheets, rules and regulations relating to
radiation protection, etc.
- Assessment of risk factors
• Operating instructions
- Instructions for practical use of the apparatus: starting-up, running, shuttingdown, safety precautions, log writing, locking-up, use of radiometer if relevant,
etc.
• Emergency procedures
Instructions may be posted locally and/or distributed to others (e.g. caretaker and
cleaners) as required. It must be considered whether English versions of documents
are needed.
5.6.4 Identifying possible exposure to radiation
Measuring the radiation properties may be an important tool for identifying potential
risks. For UV and IR lasers, fluorescent screens may represent a relevant tool for
visualising the path of the radiation. Contact the central radiation protection
coordinator at the HSE Section for assistance.
5.7 Relocating and disposing of class 3B and class 4 lasers
The NRPA [Statens strålevern] must be notified on a separate form of class 4 lasers
that are relocated or disposed of. A copy must submitted to the central radiation
protection coordinator at the HSE Section.
If class 3B lasers are relocated or disposed of, only the local radiation protection
coordinator needs to be notified, so that s/he can update the list of sources of
radiation as required by the Regulations on Radiation Protection and the Use of
Radiation [strålevernforskriften].
NTNU
Safe use of lasers
HSE
Prepared by
The HSE
section
Approved by
The Rector
Number
Date
HMSR-34
01.12.2006
Page
6 of 6
Replaces
01.12.2006
By ”relocation” is here understood permanent relocation of the laser within the unit, or
another unit taking over the responsibility and operation of the laser. In cases of
temporary relocation within the unit, a new risk assessment process must be
conducted, and the required safety measures given in this set of guidelines must be
implemented.
6. References
Forskrift om strålevern og bruk av stråling (Strålevernforskriften) (HMSR33E)
NEK EN 60825-1 Safety of laser products, Equipment classification, requirements
and user’s guide
NEK EN 60825-14 Safety of laser products, A user’s guide
Central emergency plan for accidents involving sources of radiation
HMSR26E Risk assessment
HMSR27E Room-cards
HMSR32E Distribution of responsibilities and tasks within radiation protection
HMRSV3401E Laser classes
HMRSV3402E Checklist for risk assessment before lasers are taken into use
HMRSV3403E Authorisations for unsupervised use of class 4 lasers at NTNU
HMRSV3404E Specification of materials that should go into an information binder
Description of laser classes: http://www.hpa.org.uk/radiation/faq/laser/laser9.htm
R. Henderson and K. Schulmeister (1994), Laser Safety. IOP Publishing Ltd. ISBN 0
7503 0859 1