What are the burial and reuse requirements for onshore pipelines in hydrogen service according to ASME B31.12?

Introduction

ASME B31.12 addresses the requirements for the burial depth of onshore pipelines used in hydrogen service and provides recommendations for the reuse of existing pipelines.

Answer

ASME B31.12 specifies a minimum depth of cover for buried mains in hydrogen service. For regular areas, a minimum depth of 915mm is required, while in rocky areas, it is 610mm, and in agricultural areas, it is 1219mm. The code also addresses the reuse of existing pipelines and recommends conducting a depth of cover study to ensure compliance with the cover requirement. Additionally, a minimum distance of 457mm should be maintained between buried pipelines and any other underground structures not used in the pipeline. If maintaining this distance is not feasible, the code suggests taking protective measures such as constructing casings.