How to Vet an ASME TES Tank Manufacturer: U-Stamp, Section VIII, and QA When a thermal storage (TES) tank must carry an ASME U-stamp, the manufacturer is no longer just a tank fabricator, they are a code vessel shop. The difference shows up in welding procedure qualification, radiographic inspection, and the paper trail behind every nozzle. This article is a practical checklist for qualifying an ASME TES tank manufacturer before you issue a purchase order. Key Takeaway To vet