California Code of Regulations
Title 8 - Industrial Relations
Division 1 - Department of Industrial Relations
Chapter 4 - Division of Industrial Safety
Subchapter 7 - General Industry Safety Orders
Group 20 - Flammable Liquids, Gases and Vapors
Article 138 - Hydrogen
Section 5472 - Location of Gaseous Hydrogen Systems

(a) The system shall be located so that it is readily accessible to delivery equipment and to authorized personnel.

(b) Systems shall be located above ground.

(c) Systems shall not be located beneath electric power lines.

(d) Systems shall not be located close to flammable liquid piping or piping of other flammable gases.

(e) Systems near above ground flammable liquid storage shall be located on ground higher than the flammable liquid storage except when dikes, diversion curbs, grading, or separating solid walls are used to prevent accumulation of flammable liquids under the system.