Are there any specific safety considerations regarding the transportation of hydrogen in pipelines, both steel and polyethylene?

Hydrogen affects the mechanical properties of most materials. For example, hydrogen reduces the
fracture toughness and increases the fatigue crack growth rate in steels. There is a significant amount of
research, analytical work, and codes and standards development being undertaken to improve our
understanding of how these materials can be utilized in pipelines. The results of the efforts will be
revealed as requirements in codes like ASME B31.12, Hydrogen Piping and Pipelines, and ASME B31.8,
Gas Transmission and Distribution Piping Systems, and then addressed by national regulations, such as
those provided by the US DOT Pipeline and Hazardous Material Administration (PHMSA).