API Publication 322-1994: An Engineering Evaluation of Acoustic Methods of Leak Detection in Aboveground Storage Tanks

Scope and Objectives of API Publication 322

API Publication 322, first released in December 1994, is a foundational engineering evaluation of passive acoustic methods for detecting leaks in the floor plates of aboveground storage tanks (ASTs). Developed under the American Petroleum Institute and prepared by independent engineering consultants, this publication systematically assesses the physical principles, technical feasibility, and operational limitations of using acoustic emission technology for on-stream leak detection.

The primary scope of API Publ 322 is to provide engineers and operators with an objective framework for evaluating whether acoustic monitoring can serve as a reliable leak detection method without requiring a tank to be removed from service. The publication specifically addresses the relationship between leak-generated acoustic signals and critical variables such as tank geometry, product height, fluid characteristics, foundation type, and background noise. Importantly, it also establishes performance metrics that regulators and industry stakeholders have subsequently used to gauge the acceptability of acoustic technology as part of integrity management programs under API 653 and EPA SPCC regulations.