Final rule · 2025-12079

Pipeline Safety: Standards Update-PPI-TR 4

This DFR amends PHMSA's regulations to incorporate by reference the updated industry standard PPI TR-4, PPI HSB Listing of Hydrostatic Design Basis (HDB), Hydrostatic Design Stress (HDS), Strength Design Basis (SDS), Pressure Design Basis (PDB) and Minimum Required Strength (MRS) Ratings For Thermoplastic Piping Materials or Pipe. This updated standard will maintain or improve public safety, prevent regulatory confusion, reduce compliance burdens on stakeholders, and satisfy a mandate in the National Technology Transfer and Advancement Act (NTTAA) of 1995.