PPI Listing of Hydrostatic Design Basis (HDB), Hydrostatic Design Stress (HDS), Strength Design Basis (SDB), Pressure Design Basis (PDB) and Minimum Required Strength (MRS) Ratings For Thermoplastic Piping Materials or Pipe 

Current and Previous Versions

TR-4 2021
TR-4 2020 - superseded by 2021
TR-4 2019 - superseded by 2021
TR-4 2018 - superseded by 2021
In some cases, older versions of documents are shown above for historical reference purposes only. You must always use the latest version shown here.