Fine chemicals and products of the pharmaceutical industry are produced predominantly in multi-purpose plants. Characteristically, they comprise of many recipes and very different processes. The challenge is often to adapt a certain process to a given plant. At first the sizing scenarios must be identified by means of a systematic risk analysis. Secondly, the process operation must be bounded to fulfill the requirements of the existing protection concept of the plant. This includes proper limits of the process control interlocks and the proper operation of safety devices and following disposal systems. The sizing of cyclone separators and quenches for emergency relief systems are presented and recommendations for proper industrial application of the devices are given. Short cut methods are presented to recalculate the cyclone separator and the quench in case of a change of a product in the multipurpose plant.