How Safety Found its Feet

Abstract

The Evolution of Functional Safety in Germany

This paper outlines the development of the field "plant safety by means of process control engineering" up to now and gives an outlook on the future. With the publication of IEC 61508/11, the risk to be covered is rated by safety integrity levels (SIL). Each SIL is related to a minimum-reliability of the safety instrumented system. However, due to the different conditions in the chemical industry, there no reliable failure-rates of field device are available. There was the danger of a paradigm change towards preferring extensive mathematical calculations instead of focusing on proper design. In Germany, a very good PLT-safety-concept exists that considers the engineer's expertise and has proven itself in practical use. In the future, only prior-use-devices from standard-device-lists should be used in standardized architectures. For these architectures, example calculations are available. These aspects are introduced to the international standardization by the German delegates right now. For that purpose, it is essential that companies - especially from the user side - support these activities financially. In the following, the evolution of safety is described. Starting with the corresponding Stone Age, going through Middle Ages, one reaches the Modern Age that consists of the phases "Upright Gait", "International Standardization", and necessarily following "Resurgence".