A polyethylene compression end cap is a mechanical fitting that closes the pipe end without welding. It is used with polyethylene pipes in pressurized irrigation systems, cold potable water lines, and for conveying non-corrosive liquids. Its mechanism is based on compressing the bush and O-ring onto the pipe’s outer wall as the nut is tightened; installation is quick, and the fitting can be reopened and reused.
Key Benefits & Features
- Welding-free installation; no specialized machinery
- Reliable sealing with NBR O-ring and multi-step design
- Resistant to impact and vibration along the line
- Suitable for quick repairs, temporary pressure testing, and periodic isolation
- Outdoor use possible with UV-resistant variants
- Can be removed and relocated without damaging the pipe
Applications
- Closing the pipe end after network flushing or hydrostatic testing
- Temporary isolation during phased project expansion
- Quarantining branches for periodic service
- Use in sprinkler and drip irrigation lines, landscaping, gardens & villas, and building services
Common Technical Specifications (market sample)
| Component | Range/Note |
|---|---|
| Nominal sizes | 20 to 110/125 mm |
| Nominal pressure (PN) | PN10 to PN16 depending on series and pipe SDR |
| Body/Nut material | Reinforced PP or PE with UV-resistant additive |
| Bush & grip ring | POM/acetal; toothed design for locking onto the pipe |
| Sealing O-ring | NBR (resistant to water and many lubricants) |
| Operating temperature range | About 0 to 40°C for cold water |
| Typical color | Black or black/blue; the shown sample is all-black |
| Fluid type | Cold water and non-corrosive liquids |
Size & Pressure Selection Guide
- The cap’s nominal diameter must match the pipe’s outer diameter.
- Allowable pressure depends on both the fitting PN and the pipe SDR; always take the lower value.
| Pipe OD (mm) | Inch equivalent | Common SDR for PE100 pipe | Suggested system working pressure* |
|---|---|---|---|
| 20 | 1/2″ | SDR11 | up to 16 bar |
| 25 | 3/4″ | SDR11–13.6 | 12.5–16 bar |
| 32 | 1″ | SDR11–13.6 | 12.5–16 bar |
| 40 | 1¼″ | SDR11–17 | 10–16 bar |
| 50 | 1½″ | SDR11–17 | 10–16 bar |
| 63 | 2″ | SDR11–17 | 10–16 bar |
| 75 | 2½″ | SDR13.6–17 | 10–12.5 bar |
| 90 | 3″ | SDR17 | up to 10 bar |
| 110 | 4″ | SDR17 | up to 10 bar |
- Confirm the final value based on the selected fitting PN and your project standard.
Step-by-Step Installation Guide
- Cut the pipe square and remove the external burr.
- Check the cap components (nut, grip bush, O-ring) in factory order.
- Slide the nut onto the pipe, then push the pipe into the body until it stops, ensuring it passes the O-ring.
- Hand-tighten the nut, then use a strap wrench for an extra quarter to half turn; do not use a toothed pipe wrench that may damage the body.
- Perform a leak test by increasing pressure gradually.
Common Mistakes & Prevention
- Wrong size selection: always measure the pipe OD, not the ID.
- Over-tightening: can crush the pipe and damage the O-ring. Follow the recommended torque.
- Sharp edge after cutting: ruins sealing; deburring is mandatory.
- Installing on dirty or greasy pipes: clean and dry the surface before installation.
- Mixing mismatched SDRs in one line: reduces the system’s effective pressure.
Maintenance & Inspection Notes
- After the first pressure test, check fittings for possible loosening.
- Inspect nuts and the absence of hairline cracks every 6–12 months.
- For outdoor use, choose UV-resistant variants or apply suitable protection.
- Avoid unnecessary frequent disassembly to preserve O-ring life.
Comparison with Butt-Welded and Electrofusion Types
- Compression: fast installation, recoverable, suitable for small to medium sizes and field repairs.
- Butt fusion (butt/socket): permanent joint, good for mains and large sizes; requires equipment and skill.
- Electrofusion: very reliable, traceable sealing, but higher cost and needs power and strict standards.
The final choice depends on pressure class, budget, site conditions, and operator requirements.
Price Drivers
- Size and pressure class (PN)
- Body material and O-ring quality
- Presence of UV-resistant additives
- Industrial packaging, warranty, and after-sales support
- Polymer raw-material market fluctuations
Tamambaha, as one of the suppliers of this product, can provide polyethylene compression end caps in various sizes and pressure classes for irrigation, building, and industrial projects across the Middle East. It is not the only vendor in the market; you can compare technical specifications and pricing to select the best option matching your pipe SDR, working pressure, and installation conditions.
