API 620: Low-Pressure, Refrigerated & LNG Tank Design

API 650 stops at 2.5 psig. Above that pressure, or below ambient temperature, you are in API 620 — and it is not API 650 with bigger numbers. It is a different design method built on different theory.

The one-foot method does not apply. Shell thickness comes from biaxial membrane analysis, calculating meridional and latitudinal stress at every level of the tank. The roof-to-shell junction becomes a compression ring region that must be sized for the resultant compressive force. Internal pressure creates uplift that anchorage must resist. And in refrigerated service, everything changes again — materials, foundations, insulation, containment philosophy.

This course teaches that method as an engineering discipline, worked step by step.

WHAT YOU WILL MASTER

Five sections take you from code scope and configuration selection, through biaxial shell and roof design, into bottom, anchorage and foundation design, then refrigerated and cryogenic tanks under Appendices Q and R, and finally fabrication, testing, cool-down and handover.

You will work the biaxial equations through a full shell profile. You will size a compression ring. You will design anchorage against pressure uplift, wind and seismic. You will select materials down to minus 270 degrees Fahrenheit, including 9% nickel steel for LNG service, and understand why single, double and full containment configurations exist and when each is required.

A SCARCE AND WELL-PAID SPECIALISM

Very few mechanical engineers can design a refrigerated tank. LNG import and export terminals, ammonia storage, LPG facilities and the growing hydrogen and CO2 storage sector all need engineers who can — and there are far fewer of them than the work requires. This is a capability that changes what projects you can be put on.

TAUGHT AS DESIGN, NOT AS CODE RECITAL

Every method is built up with the engineering logic behind it, so you understand why the code says what it says. That is what you need when a real design falls outside the neat case. No filler, no clause-by-clause narration — a focused course you can work through in a few evenings.

WHO THIS IS FOR

Mechanical, structural and cryogenic engineers designing or specifying low-pressure and refrigerated tanks; terminal and project engineers reviewing vendor designs; tank inspectors who need the design basis behind what they are inspecting; and graduate engineers building a foundation in a specialism with very little competition.

WHAT YOU GET

Structured on-demand video across 20 focused lessons and five sections, section quizzes and a final exam, lifetime access on mobile and TV, a certificate of completion, and Udemy's 30-day money-back guarantee.

No prior tank design experience is needed — the code context and design logic are built from the ground up. No software required; every method follows API 620 directly.

Enrol now and add a genuinely scarce engineering skill to your name.