A Preliminary Study of the Application of Probabilistic Risk Assessment Techniques to High-Energy Laser Safety

Abstract

Abstract : A deterministic approach to laser hazard assessment is used in most laser safety standards. Personnel are protected from hazardous laser radiation by defining a space within which the direct, reflected, or scattered radiation during laser operation exceeds the safe Maximum Permissible Exposure level. Controlling access to this space insures safety. Although this approach has satisfied the commercial and industrial laser communities for many years, it may not be applicable to the high-power (up to megawatt) laser systems currently being developed by the U.S. Military. These systems will have extremely long laser hazard distances, and controlling access to this space will be unrealistic, especially when the likelihood of hazardous human exposure is low. For these situations, an alternate analytical approach that estimates both the level of risk and the degree of risk reduction achievable by controlling key contributors can be applied. Analytic risk assessment tools are finding increasing application in a wide variety of hazard assessments, in both industrial and commercial situations. These tools use scientific data, assumptions, and mathematical models to estimate the likelihood, frequency, and severity of harm to people exposed to the hazard. This report discusses the application of such tools to laser safety and considers the uncertainties associated with probability density functions applied to key factors such as atmospheric scintillation, reflected radiation, population distribution and ocular injury.