Interplay of technical specifications and technical developments in the safety of chemical plant. In the planning, construction, and operation of chemical plant requiring close supervision the aims are defined by rules and regulations which refer back to a comprehensive compilation of technical specifications concerning the means by which these aims can be accomplished. These rules were, and are, worked out by business federations in collaboration with occupational and governmental agencies in joint committees. Since both practical experience and fresh knowledge resulting from technical developments are gained in industrial undertakings, the feedback of experience from industry ensuring continuous up‐dating of the technical specifications is of immense importance. Starting from the current state of the art, the expert frequently has to work out solutions to specific problems. Once general conclusions which have proved their value in practice can be derived, they are incorporated in the technical specifications. Such a contribution to safety engineering is illustrated for a pressure vessel. The examples described range from the derivation of reliable criteria for assessing the danger of brittle fracture of high‐strength steel pressure vessels to the development of preventative techniques of nondestructive testing of components. They also incorporate the development of design data for conservative dimensioning of safety valves for frothing mixtures and their safe release into the atmosphere as well as investigation of the pressures expected on explosion of flammable hydrocarbon/air mixtures.