Laser Safety Eye Examinations for Laser Workers Policy

Document Number000178

1.      Introduction

This policy is based on Australian/New Zealand Standard 2211.1:2004 "Laser Safety" and
refers to those persons whose activities involve the use of a laser and a significant risk of
exposure to laser radiation in excess of the maximum permissible.

The objectives of this policy are as follows:

1.1.     To protect persons from laser radiation in the wavelength range 100 nm to 1 mm* by indicating

safe working levels of laser radiation and by introducing a system of classification of lasers and
laser products according to their degree of hazard.

* In this Standard, the wavelength range l1 to l2 means l1 £ l < l2 (eg 100 nm to 1 mm means
100 nm £ l < 1 mm)

1.2.     To lay down requirements for the user to establish procedures and supply information so that

proper precautions can be adopted.

1.3.     To ensure adequate warning to individuals of hazards associated with accessible radiation from

laser products through signs, labels and instructions.

1.4.     To reduce the possibility of injury by minimising unnecessary accessible radiation, and to give

improved control of the laser radiation through protective features and provide safe usage of
laser products by specifying user control measures.

2.      Classification of Lasers

2.1.     Introduction

Because of the wide ranges possible for the wavelength, energy content and pulse
characteristics of a laser beam, the hazards arising in their use vary widely. It is impossible to
regard lasers as a single group to which common safety limits can apply.

2.2.     Description of Laser Classes

Laser products are grouped into four general classes for each of which accessible emission
limits (AELs) are specified.

Class 1 lasers are those that are inherently safe (so that the maximum permissible exposure
(MPE) level cannot be exceeded under any condition), or are safe by virtue of their engineering
design.

NOTE: The upper limits for Class 1 lasers are given in Table 1 and are derived from the most
limiting MPE values.

Class 2 lasers are low power devices which emit visible and invisible radiation and which may
operate in either CW or pulsed mode. The output power or energy of these systems is limited
to:

  1. the AELs in Table 1 for Class 1 lasers for invisible radiation;
  2. the AELs in Table 1 for Class 1 lasers for visible radiation with exposure durations less
    than 0.25 s; and
  3. the AEL in Table 2 for lasers for visible radiation with exposure duration greater than or
    equal to 0.25 s (ie 1 mW for CW lasers).

NOTE: These lasers are not intrinsically safe but eye protection is normally afforded by aversion responses including the blink reflex. Class 3A lasers emit higher levels of radiation than Class 2. For example, in the visible range (400 nm to 700 nm) they may have a CW output power up to 5 mW, provided the maximum irradiance at any point in the beam does not exceed 25 W.m-2 (see Table 3 for specific wavelength and time dependent limits).

NOTE: Direct intrabeam viewing of Class 3A laser beams with optical aids (eg. binocular
telescopes) may be hazardous. For lasers emitting radiation in the range from 400 nm to 700
nm, protection to the unaided eye is afforded by aversion responses including the blink reflex.

Class 3B (Restricted) lasers operate at the same power levels as Class 3A, but have higher
levels (≤ 50 W.m-2) of irradiance (power density). They may be used in daylight conditions, where the pupil diameter will not be greater than 5 mm, under the same safety controls as for

Class 3A. Where used in conditions of lesser illuminance, the appropriate safety controls are those specified for Class 3B.

Class 3B lasers may emit visible and/or invisible radiation at levels not exceeding the AELs
specified in Table 4. CW lasers may not exceed 0.5 W and the radiant exposure from pulsed lasers must be less than 105 J.m-2.

NOTES:

  • Direct intrabeam viewing near Class 3B lasers is always hazardous. Viewing
    unfocused pulsed laser radiation by diffuse reflection is not hazardous and, under
    certain conditions, CW laser beams may safely be viewed via a diffuse reflector.
  • These conditions are:
    • a minimum viewing distance of 13 cm; and
    • a maximum viewing time of 10 s
  • If the conditions in Note 1 are not satisfied, careful evaluation of the potential diffuse
    reflection hazard is necessary.

Class 4 lasers are high power devices with output powers exceeding the AELs specified in
Table 4 for Class 3B.

NOTE: All Class 4 lasers are capable of producing hazardous diffuse reflections. They may
cause skin injuries and could also constitute a fire hazard. Their use requires extreme caution.

3.      User Obligations

3.1.     It is a responsibility of the supervisor of users of any laser other than the Class 1 to ensure that

operations are in accord with Section 3 of the Australian/New Zealand Standard 2211.1:1997
on "User’s Guide". Laser workers working with Class 4 or Class 3B (except Class 3B
(Restricted)) lasers must follow the Medical Monitoring Procedure specified below.

4.      Medical Monitoring Procedure

4.1.     All staff members and students working with lasers, for teaching and/or research purposes, as

specified above must have eye examinations as follows:

  1. at the commencement of work,
  2. termination of work, and
  3. biannually while the work continues.

4.2.     Examinations will be performed by the University Health Service. The cost is to be met by the

School in which the staff member or student is located.

4.3.     Eye examinations are to be carried out as specified under Item 12.14 "Medical Surveillance" of Australian/New Zealand Standard 2211.1:1997.

5.      Procedures to be Followed in the Event of an Abnormality being Detected

5.1.     In the event that an abnormality is detected by the University Health Service, the person will be immediately referred to an ophthalmologist for further investigation. Should this specialist

investigation reveal radiation damage, a full biophysical investigation of the circumstances
under which the accident occurred will be conducted.

The University Health Service shall refer the results of this investigation to the Australian
Radiation Laboratory. A report on the outcome is to be referred to the University Organisational
Health and Safety Manager for appropriate action.

NOTE: All tables referred to in this policy can be sighted in the AS/NZS
2211.1.:2004.

Approval AuthorityVice-Chancellor
Policy SponsorDeputy Vice-Chancellor (Services)
Policy OwnerDirector, Human Resource Services
Policy ContactAssociate Director, Health, Safety & Environment