October 15, 2026 · Indumor
API 650 is the bible of storage tanks. Period.
The American Petroleum Institute has been refining this standard for nearly a century, and today virtually every welded vertical tank storing hydrocarbons at atmospheric pressure — from the small plant tank to the refinery giant — is designed and built under its rules. When a spec, an insurer or an audit says "the tank shall be API 650", they are saying something very concrete: that every decision — which plate to use, what thickness each shell course carries for its liquid head, how bottom, shell and roof get welded, who is qualified to weld, and which tests prove it was all done right — follows a written, auditable, globally recognized criterion. It is not a sticker applied at the end: it is a way of fabricating from start to finish. The opposite also exists, of course: the "artisanal" tank somebody sized by eye — which works great right up until the day it does not.
Three big things. Materials and thickness: each shell course is calculated from the real liquid pressure at that height; no "quarter-inch everywhere because that is how we always did it". Welding: qualified procedures, qualified welders, and specific joint details for bottom, shell and roof. Verification: weld radiography on a sampling plan, dye penetrant and vacuum box on the floor, and a hydrostatic test filling the tank with water before it ever sees a drop of fuel. At Indumor we apply these guidelines on our fuel storage tanks, and the test protocol travels with every tank.
When does it apply to you? If you are building or expanding hydrocarbon storage, the moment to demand the standard is before the first plate is cut, not after. If your project has a date on it, write to us this week and we will quote it with the testing plan included — export shipping too.
We quote your API 650 tank with the testing plan included.
© Indumor 2010–2026 — Industrial steel fabrication, Córdoba, Argentina
