PEX Tubing vs. PVC DWV Pipe
Comparing 2 standards across 13 specifications. 13 key differences identified.
Cross-linked Polyethylene (PEX) is flexible plastic potable water and radiant heating tubing standardized under ASTM F876 and F877. Classified by cross-linking manufacturing chemistry into PEX-A (Engel cold expansion), PEX-B (Silane crimp/clamp), and PEX-C (Radiation), PEX adheres to Copper Tube Size (CTS) outer dimensions with SDR-9 pressure ratings.
Schedule 40 PVC DWV (Drain-Waste-Vent) pipe governed by ASTM D2665 is the standard rigid white thermoplastic pipe for residential and commercial gravity sanitary drainage, waste discharge, and sewer venting. Engineered with smooth non-porous bore walls to prevent clogs, it joins via chemical solvent cement welding.
Specification Comparison Table
13 Parameters| Parameter / Spec | ||
|---|---|---|
|
Governing Standards
|
ASTM F876 / ASTM F877 / CSA B137.5 / NSF 61 / NSF 14 | ASTM D2665 / ASTM D1785 / CSA B181.2 / NSF-dwv |
|
Standard Dimension Ratio
|
SDR-9 (OD to wall thickness ratio = 9:1) | — |
|
PEX-A (Engel Method)
|
>85% cross-linking | Extreme flexibility & thermal shape memory (ASTM F1960) | — |
|
PEX-B (Silane Method)
|
65–70% cross-linking | High chlorine resistance (ASTM F1807 / F2159) | — |
|
PEX-C (Electron Beam)
|
60–65% cross-linking | Eco-friendly manufacturing process | — |
|
Pressure Ratings
|
160 PSI @ 73.4°F (23°C) | 100 PSI @ 180°F (82°C) | 80 PSI @ 200°F (93°C) | — |
|
Bend Radius Minimum
|
6× outer diameter (PEX-A can bend tighter to 5× OD) | — |
|
1-1/2" DWV Dimensions
|
— | OD: 1.900" (48.3 mm) | Min Wall: 0.145" (3.68 mm) | Sinks, tubs, showers |
|
2" DWV Dimensions
|
— | OD: 2.375" (60.3 mm) | Min Wall: 0.154" (3.91 mm) | Washing machines, floor drains |
|
3" DWV Dimensions
|
— | OD: 3.500" (88.9 mm) | Min Wall: 0.216" (5.49 mm) | Water closets (toilets), soil stacks |
|
4" DWV Dimensions
|
— | OD: 4.500" (114.3 mm) | Min Wall: 0.237" (6.02 mm) | Main building sewer drain |
|
Primary Joining Method
|
— | Purple primer + solvent cement (chemical molecular fusion weld) |
|
Maximum Operating Temperature
|
— | 140°F (60°C) continuous service |