ASME NM.3

Covers — material specifications, design/allowable values, properties, temperature limits, and cautions for nonmetallic (thermoplastic and reinforced-thermoset) pressure-piping materials used by ASME NM.1 and NM.2.

Does NOT cover (exclusions) — the thermoplastic system design → ASME NM.1; the FRP system design → ASME NM.2; metallic material data → ASME BPVC Section II.

NM.3 is the nonmetallic material-data source; NM.1/NM.2 are the design codes that use it.

NM.3 provides material data:

• Specifications — accepted thermoplastic and reinforced-thermoset material specs.
• Design/Allowable Values — stresses and design values versus temperature and time.
• Properties & Limits — physical/mechanical properties and temperature limits.
• Cautions — chemical-compatibility and service cautions.

ASME NM.3 is the nonmetallic material-data standard that underpins the ASME nonmetallic piping codes — it is to NM.1 (thermoplastic) and NM.2 (FRP) what BPVC Section II is to the metallic codes. It provides the material specifications, design/allowable values versus temperature and time, properties, temperature limits, and service cautions.

In practice, the system is designed to NM.1 or NM.2 while the material design values come from NM.3. Getting the right values — especially the temperature- and time-dependent strength — is essential for nonmetallic piping that derates strongly with both.

Engineering Note: Use the correct NM.3 design value for the actual temperature and design life — a nonmetallic line designed on room-temperature, short-term strength can be badly overstressed at operating temperature over decades of service.