Hazard evaluation and laser device classification

• Pages: 6-12

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Hazard evaluation and laser device classification

4.1 General concepts of hazard evaluation and risk assessment

Four aspects of the use of lasers need to be taken into account in the evaluation of

possible hazards, the assessment of risk of injury and in the application of control

measures:

(a) The capability of the laser or laser system to injure personnel determines its

"hazard classification". This includes consideration of human access to the main

exit port or any subsidiary port of the laser beam. Certain hazard controls are built

into commercially manufactured lasers or laser systems (IEC, 1984, 1990). The

concept of risk is included in the scheme of "hazard" classes.

(b) The environment in which the laser is used.

(c) The level of training of the personnel who operate the laser or who may be

exposed to its beam.

(d) The intended use of the laser.

The practical means for evaluating laser radiation hazards and assessing risk of

exposure is to first determine the hazard classification of each laser system. The hazard

class indicates the laser's relative hazard potential and may also incorporate an

assessment of risk of exposure to potentially hazardous levels of laser radiation.

Appropriate controls are specified for each class. The use of the classification system

will, in most cases, preclude any requirement for radiometric measurements and a

detailed risk assessment by the user.

In the standardized laser classification scheme, aspect (a) (the potential hazard of

the laser or laser system) is defined. Aspects (b) and (c) vary with each use and cannot

be readily included in a general classification scheme. In total hazard evaluation and risk

assessment procedures, all four aspects must be considered, although in most cases

aspects (a) and (d) are sufficient to determine the control measures applicable.

4.2 Classification of laser devices

The hazard and risk classification scheme given below is based on the output

parameters and accessible levels of radiation. This classification takes largely into

account that of the IEC (1984) the US Food and Drug Administration (FDA, 1989) and

that used by ANSI (1986). The laser device classification normally will appear on many

commercial laser products manufactured subsequent to the adoption of these standards.

This classification should be used unless the laser is modified so as to change its output

power or energy significantly. The classes are:

1. laser systems that are not hazardous (without known biological hazards);

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