Published standards required for equipment and working practices within the chemical and process industries that represent good practice and define the level or standard of design. Developed and evolved over many years and based on tried and tested practices, there are a number of national standards organizations and institutions that provide published standards for design, materials, fabrication, and testing of processes and equipment. These include the British Standards Institute (BSI), the Institute of Petroleum (IP), the American Petroleum Institute (API), the American National Standards Institute (ANSI), the American Society of Mechanical Engineers (ASME), the American Society for Testing and Materials (ASTM), and the American Iron and Steel Institute (AISI). In Europe, there has been a steady move towards harmonization of national standards with the formation of the Euronorm (EN) engineering standards.