Consideration of accident preventive structures based on risk assessment

It has passed more than ten years since the risk assessment was made mandatory to be a non-binding target by the Industrial Safety and Health Act. Accordingly, various measures have been taken by domestic companies until today. On the other hand, the risk assessment is importantly positioned by ISO 12100 (Safety of Machinery - Basic Concepts, General Principles for Design, Risk Assessment and Risk Reduction) and ISO 45001 (OSHMS, Occupational Safety and Health Management Systems - Requirements). Generally, it may be said that the risk assessment is designed to attain the “tolerable risk” as defined by ISO/TEC Guide 51. However, even if risk reduction is implemented, as long as residual risk remains, fatal accidents due to the residual risk cannot be prevented completely. On another front, the notion that a purpose of the risk assessment is to determine the stop category, which is accepted as a critical view to global security, seems not to be understood completely in Japan. In this study, therefore, the authors give consideration to the relations between the risk assessment and the stop category, and provide further insights into the stop category to be determined by safety assured by means of control based on “stop prior to accident” as the common principle.