Joining Other than Welding (10)

Joining Other than Welding (10)

Criticality: High
Progress: Not Addressed
Score: 40
DOT Relevance: 192.271 192.287

Description of Key Area

Subpart F of 49 CFR 192 refers to requirements for joining materials in pipelines other than by welding. It does not apply to joining during the manufacture of pipe or pipeline components. Joining by welding is addressed in subpart E (Welding of Steel in Pipelines, 192.221 to 192.245). Joining, in general, may take place by welding of steel, or joining of pipes other than steel, such as plastic pipe or composite pipe. Plastic pipe is joined by fusion. Composite pipe might be joined by combinations of mechanical joining and some type of fusion.

Discussion of Criticality

It is important that all joining methods used be adequate to prevent leakage, permeation of hydrogen, or pipe embrittlement.

Discussion of Progress

No information found.


Appropriate joining techniques must be documented and tested for hydrogen applications. In addition, standards for flange gaskets and other sealant materials for steel pipe used for hydrogen applications need to be established. A definition for a qualified joint must be created. Operator training and qualification must be developed for the joining methods. Standards for joining (other than by welding) must be established and incorporated by reference to the federal code.

ASME B31.12 will reference consensus standards that adequately cover the mechanical joining of pipes in hydrogen service. Performance testing is required and should be performed to a national standard. System design and joint design may dictate what can and can not be mechanically joined.