Thermoplastic Couplings
Pipe-to-Pipe Connectors for Socket-Weld or Butt-Weld Assembly
DN 20 – DN 200
Size Range
Socket / Butt / Threaded
Connection
PP / PPH / PVDF
Material
PN 6 / 10 / 16
Pressure
Couplings for Joining Thermoplastic Pipe Sections
UNP’s Thermoplastic Couplings provide a simple straight-through connection between two pipe sections of the same diameter. Used wherever you need to join two pipe ends — mid-line junctions, repair patches, or extending an existing run.
Socket-weld couplings have machined sockets at both ends sized to accept standard pipe OD for heat-fusion assembly. Butt-weld couplings have plain ends bevelled for direct end-to-end fusion. Threaded couplings (BSP or NPT) are available for serviceable connections.
Same material (PP, PPH, PVDF, ISO.PP) and pressure rating as the pipe it joins — ensuring the coupling is never the weakest point in the line.
Why Choose This Fitting
- ✓Same-diameter pipe-to-pipe joining
- ✓Socket weld / butt weld / threaded ends
- ✓Same pressure rating as joined pipe
- ✓PP / PPH / PVDF materials
- ✓Sizes DN 20 through DN 200
Dimensions, Materials, Testing
Coupling Dimensions
All dimensions in millimeters unless noted.
| Pipe Size | OD (mm) | Coupling Length (mm) | Socket Depth (mm) | Wall Thk (mm) |
|---|---|---|---|---|
| 20 | 20 | 30 | 15 | 2.3 |
| 25 | 25 | 40 | 18 | 2.9 |
| 32 | 32 | 45 | 22 | 3.7 |
| 40 | 40 | 55 | 26 | 4.6 |
| 50 | 50 | 65 | 30 | 5.8 |
| 63 | 63 | 75 | 38 | 6.8 |
| 75 | 75 | 90 | 46 | 8.2 |
| 90 | 90 | 105 | 51 | 9.0 |
| 110 | 110 | 125 | 61 | 10.0 |
| 125 | 125 | 135 | 69 | 11.4 |
| 160 | 160 | 170 | 86 | 14.6 |
| 200 | 200 | 205 | 106 | 18.2 |
Materials of Construction
| Material | Description |
|---|---|
| PP (Polypropylene) | General-purpose, low-cost option for mildly corrosive media at moderate temperatures. |
| PPH (Polypropylene Homopolymer) | Higher mechanical strength than PP — better for pressure service. |
| PVDF (Polyvinylidene Fluoride) | Superior abrasion resistance and high mechanical strength. |
| ISO.PP (Isotactic Polypropylene) | Improved temperature and chemical resistance vs standard PP. |
Connection Types Available
| Connection | Description |
|---|---|
| Socket Weld | Heat-fused socket joints for permanent, leak-tight assemblies. |
| Butt Weld | End-to-end heated fusion for in-line pipe sections. |
| Threaded | Removable threaded fittings for serviceable connections. |
| Flanged | Bolted flange joints for easy disassembly and inspection. |
Testing & Quality
| Test | Standard / Result |
|---|---|
| Hydrostatic Test | BS EN 12266-1 / DIN 8077 / DIN 8078 |
| Visual / Dimensional Inspection | 100% Sampled |
| Pressure Rating | PN 6 / PN 10 / PN 16 (depending on size & material) |
| Temperature Range | 0°C to 80°C (PP) / 0°C to 95°C (PPH) / -40°C to 140°C (PVDF) |
| Certifications | ISO 9001:2015 |
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Order Your Thermoplastic Couplings
Tell us your pipe size, material, and connection type — we’ll supply matching couplings for your assembly.