This guide provides an overview of the essential factory tests and certifications required for ASME custom vessels, including procedures such as hydrostatic, pneumatic, radiography, and material traceability to ensure compliance and quality assurance. It also explains the significance of certifications like the ASME U and UM marks, National Board (NB) mark, PED, CRN, and UN ratings, which validate that vessels meet rigorous industry and international standards for safety and performance.