Pennsylvania Code
Title 34 - LABOR AND INDUSTRY
Part I - Department of Labor and Industry
Chapter 14a - STORAGE AND USE OF FLAMMABLE AND COMBUSTIBLE LIQUIDS
Subchapter C - SPECIAL PROVISIONS AND PROCEDURES
PROTECTION OF TANKS IN FLOOD AREAS
Section 14a.213 - Underground tanks

(a) At locations where there is an ample and dependable water supply available, underground tanks containing flammable or combustible liquids, so placed that more than 70% of their storage capacity will be submerged at the maximum flood stage, shall be so anchored, weighted or secured as to prevent movement when filled or loaded with water and submerged by flood water to the established flood stage. Tank vents or other openings which are not liquid tight shall be extended above maximum flood stage water level.

(b) At locations where there is no ample and dependable water supply or where filling of underground tanks with water is impractical because of the contents, each tank shall be safeguarded against movement when empty, and submerged by high ground water or flood water by anchoring or by securing by other means. Each such tank shall be so constructed and installed that it will safely resist external pressures if submerged.