Where the application permits, the use of gravity instead of a pump makes this system the most cost-effective option for combustible liquid storage. Gravity Flow Above Ground Storage Tanks (AST) have quickly become a favorite choice for storing combustible liquids. Easy to use and install, gravity flow stand mounted ASTs are available in single wall and double wall versions. Best of all, they are designed and manufactured by Westeel to provide years of worry-free service, and superior protection against costly and environmentally damaging leaks or ruptures. Typical applications are petroleum refueling facilities (agricultural fleet and equipment) and petroleum processing (oil and gas chemicals, enhancers, additives)