# Pipeline Safety: Standards Update-PPI-TR 4
> **Pipeline and Hazardous Materials Safety Administration** · Direct final rule (DFR); request for comments. · Published 2025-07-01 · Effective 2026-01-01 · 90 FR 28075
## Document
- **Document number:** 2025-12079
- **Category:** pipeline-safety
- **Sub-agency:** Pipeline and Hazardous Materials Safety Administration
- **Federal Register citation:** 90 FR 28075
- **CFR reference:** 49 CFR 192
- **Publication date:** 2025-07-01
- **Effective date:** 2026-01-01
- **DOT docket:** Docket No. PHMSA-2025-0132
## Abstract

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.

## Source
- [Federal Register document](https://www.federalregister.gov/documents/2025/07/01/2025-12079/pipeline-safety-standards-update-ppi-tr-4)
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