ASME NM.1

Covers — design, materials, fabrication, joining, installation, examination, and testing of thermoplastic pressure piping (PVC/CPVC/PE/PP/PVDF, etc.) within the ASME framework.

Does NOT cover (exclusions) — reinforced thermoset (FRP) piping → ASME NM.2; nonmetallic material design values → ASME NM.3; metallic process piping → ASME B31.3.

NM.1 is the ASME thermoplastic-piping code; FRP uses NM.2 and both draw material data from NM.3.

NM.1 sets minimum requirements for thermoplastic piping:

• Materials — thermoplastic material selection with design values from NM.3.
• Design — pressure design accounting for temperature derating and long-term strength.
• Joining & Fabrication — solvent cementing, fusion, and mechanical joining.
• Examination & Testing — inspection and pressure/leak testing.

ASME NM.1 is the ASME code for thermoplastic pressure piping — PVC, CPVC, PE, PP, PVDF and similar — bringing plastic piping into the same framework as the metallic B31 codes. It covers design (with temperature derating and long-term strength), materials, joining (solvent cement, fusion), installation, examination, and testing, using the material design values in ASME NM.3.

It provides an ASME-code route for plastic process piping alongside the metallic lines governed by B31.3, while reinforced thermoset (FRP) piping is handled by the companion ASME NM.2.

Engineering Note: Apply the temperature-derating and long-term-strength basis rigorously — thermoplastics lose pressure capacity with both temperature and time, so a design that ignores derating or the 50-year strength regression can fail well within service life.