Occupational exposure limits and safety standards

• Pages: 17-23

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Occupational exposure limits and safety standards

6.1 The IRPA/INIRC guidelines on limits of exposure to laser

radiation

6.1.1 Background

The International Non-Ionizing Radiation Committee (INIRC) of the

International Radiation Protection Association (IRPA) first published guidelines on

limits of exposure to laser radiation in 1985. Since that time, as a result of an expanded

laser database, the guidelines were revised in 1988.1 Prior to presenting the guidelines

on laser exposure, it is worthwhile explaining the process by which IRPA/INIRC

develops guidelines on non-ionizing radiation (NIR).

6.1.2 Exposure limits

Exposure limits in standards are expressed in terms of radiant exposure (J/m² or

J/cm²) or irradiance (W/m² or W/cm²) for direct exposure or respectively integrated

radiance (J/m².sr or J/cm².sr) and radiance (W/m².sr or W/cm².sr) for extended sources.

The development of exposure limits requires a valid assessment of the possible

biological effects and of the exposure-response relationship as well as appropriate

information on the various sources in use, the resulting levels of exposure and the

people at risk. It also requires a protection philosophy which links the above knowledge

with the general aims of occupational health protection. As noted above, the basic

resource document used for the development of the laser exposure limits was the

Environmental Health Criteria Document (WHO, 1982). The data base of laser

biological effects upon the human eye and skin reviewed in the criteria document was

the same as that used by other national and international organizations to derive

exposure limits and, not surprisingly, the IRPA exposure limits are generally in

agreement with those of the International Electrotechnical Commission (IEC, 1984,

1990), the American Conference of Governmental Industrial Hygienists (ACGIH,

1991), the American National Standards Institute (ANSI, 1986), the British Standards

Institute (BSI, 1984), the Health Council of the Netherlands (HCN, 1979), the Deutsche

Institut für Normung, (DIN, 1984) and others.

A summary of the IRPA exposure limits is given in tables 3(a), 3(b) and 3(c).

1 A. S. Duchêne et al. (eds.): IRPA guidelines on protection against non-ionizing radiation (New

York, Pergamon Press, 1991), Ch. 4.

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