Hazard Evaluations

The University of Ottawa is using many types of laser systems for a variety of purposes, such as teaching, research, laboratory experiments, etc. It is not uncommon to find different classes of lasers in a single laboratory. Laser hazard evaluations and the application of appropriate controls must rely on the following five aspects:

(1) The laser or laser system's capability of injuring personnel

(2) The beam path of the laser radiation

(3) The environment in which the laser is used

(4) The personnel who may use the laser or be exposed to laser radiation

(5) The interaction of the beam with its intended target

Lasers are classified into 7 classes (see Laser Classification) according to the level of hazard they create. There are three elements that form the basis of the laser hazard evaluation that each user must be aware of prior of using a laser:

(1) MPE - Maximum permissible exposure: the level of radation to which a person may be exposed without expected hazardous effects (W/m2)

(2) NHZ - Nominal hazard zone: the space in which the level of direct, reflected or scattered radiation during normal operation exceeds the applicable MPE(m)

(3) LCA - Laser controlled area: the area is defined to contain laser radiation. The room or enclosure must shield the public areas to ensure that members of the public may not be inadvertently exposed to laser radiation or non-beam hazards associated with the use of laser.

Non-Beam Hazards include:

  • fires (electrical or laser produced)
  • production of toxic gases, fumes, and aerosols (Laser Generated Air Contaminates (LGAC))
  • improper ventilation
  • electrical hazards (unprotected wiring)
  • spills (water, dye, chemical)
  • lack of MSDS for gases and laser/target by-products
  • access control (both in terms of room access and to laser beam)
  • lack of hazard signage
  • interlocks defeated, not functional or present
  • no lock-out / tag-out provisions

Operator and Third Party considerations:

  • the maturity of judgement of the laser operator(s)
  • general level of training
  • awareness of onlookers of potential hazards and safety precautions
  • degree of laser safety training
  • reliability of users to follow standard operator and safety practices
  • number of individuals and their location in the room ,(in relation to primary and secondary beam hazards)
  • other hazards in the room which may result in an unexpected action of an individual, influencing the laser operation
  • the potential access to the laser facility of untrained parties (housekeeping, maintenance and trade personnel, visitors)


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