Louisiana Administrative Code
Title 43 - NATURAL RESOURCES
Part XI - Office of Conservation-Pipeline Division
Subpart 5 - Compressed Natural Gas
Chapter 55 - Design
Section XI-5503 - Design and Construction of Cylinders and Pressure Vessels (Formerly section 2521)

A. Cylinders and pressure vessels shall be fabricated of steel, aluminum, or composite materials.

B. Cylinders shall be manufactured, inspected, marked, tested, and retested in accordance with U.S. Department of Transportation (DOT) regulations and exemptions for compressed natural gas (CNG) service. Fuel supply cylinders shall have a rated service pressure of not less than 2,400 psig at 70°F. Cascade storage cylinders shall have a rated service pressure of not less than 3,600 psig at 70°F. Note: Currently, there are no cylinder specifications in DOT regulations for CNG. Current documents covering these cylinders are DOT exemptions. These are single purpose documents issued to a single company for a specific CNG application.

C. Pressure vessels and containers other than cylinders shall be manufactured, inspected, marked, and tested in accordance with the "Rules for the Construction of Unfired Pressure Vessels," "American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code, Section VIII (Division 1)."

D. In addition to other marking requirements, cylinders shall be labeled with the words, "FOR CNG ONLY" in letters at least 1 inch high in a contrasting color and in a location which will be visible after installation. Decals or stencils are acceptable.

E. Field welding or brazing for the repair or alteration of a cylinder or ASME pressure vessel is prohibited.