Obsolescence is a significant risk factor for an organisation and/or a programme activity regarding the continuity of productions, services and maintenance in operational conditions of equipments and systems. It can appear in any phase of the product life cycle. Thus it is essential that the organisation determines the best strategy to be implemented in order to control these risks, implying its customers and suppliers in the definition of this strategy. This recommendation is a document meant to be used as guidelines, for an organisation and/or a given programme, for the implementation of a coordinated management process of obsolescence risks related to chemical products and to their effects on products, especially on materials, processes and mechanical parts. Can be subject to obsolescences: all categories of equipments as well as their components; materials and processes used to produce, operate or maintain a product; all that can be bought, manufactured, repaired, be it done internally or externally; means of production, test and maintain. This document excludes obsolescences related to electronic components and softwares (for more information on that subject see EN 62402).