To evaluate the practical benefits of non-welded piping technology, a comparative installation study was conducted at the Alusa/Petrobras COMPERJ project in Brazil. The objective was to compare a conventional welded piping system against a Pyplok® mechanically attached piping system under identical fabrication and testing conditions.
Two steam lines of identical material specification, pipe diameter, geometry, and number of joints were selected. Both assemblies were fabricated by the same team, under the same workshop conditions, and subjected to identical dimensional inspections and hydrostatic testing requirements. This approach ensured that the joining method itself was the only variable being evaluated.
The selected test lines were:
1"-AV-2400-444-Ce-IQ – Conventional hot-work process using welded socket connections and flanges.
1"-AV-2400-442-Ce-IQ – Pyplok® cold-compression process using mechanically attached fittings.
Test Methodology
To ensure a fair comparison, both piping systems underwent:
1. Identical pipe preparation procedures.
2. The same cutting and joint preparation activities.
3. Installation by the same fabrication team.
4. Dimensional inspection by qualified personnel.
5. Hydrostatic testing in accordance with project specifications.
The only variable was the joining method used to assemble the piping system.
Conventional Welding Process
The welded piping spool required the following activities:
1. Material preparation
2. Pipe cutting
3. Joint preparation
4. Spool assembly
5. Tack welding and alignment
6. Dimensional inspection
7. Final welding
8. Dye penetrant/NDT inspection
9. Hydrostatic testing
In addition to labour, the welding process introduces indirect costs associated with qualified welders, hot-work permits, fire watch personnel, radiographic inspection, weld repair, gas freeing, flushing, and production disruptions.
Pyplok® Cold Compression Process
The welded piping spool required the following activities:
1. Material preparation
2. Pipe cutting
3. Joint preparation
4. Spool assembly
5. Swaging of fittings using a hydraulic Pyplok® tool
6. Dimensional inspection
7. Hydrostatic testing
Because the connection is made through a 360° radial swaging process, no welding, brazing, threading, or NDT inspection of welds is required. The installation is completed as a cold-work activity, eliminating many of the support activities associated with hot work.
Pyplok® Cold Compression Process
The Alusa/Petrobras comparison demonstrated a substantial reduction in fabrication time when using the Pyplok® cold-compression process.
For the installation of 12 joints:
1 .Conventional welding required 231 minutes.
2 Pyplok® required 98 minutes.
3. Average installation time per joint was reduced from 19.25 minutes to 8.2 minutes.
4. Both systems successfully passed hydrostatic testing at 31.5 bar without leakage.
Results
| Conventional Welding | Pyplok® | |
|---|---|---|
|
Number of Joints |
12 |
12 |
|
Total Installation Time |
231 min |
98 min |
|
Average Time per joint |
19.25min |
8.2min |
The Pyplok® installation reduced execution time by approximately 58%, while achieving the same functional outcome as the welded system.
Performance Verification
Both piping systems successfully completed hydrostatic testing at 31.5 bar without leakage. An additional pressure test performed on a separate Pyplok® test assembly reached 250 kg/cm² without leakage, demonstrating the integrity of the swaged connection.
Beyond Labour Savings
While installation speed is a major advantage, the true project savings often come from eliminating secondary activities such as:
1. Hot-work permits.
2. Fire watch personnel
3. Radiography and NDT inspections
4. Weld repairs and re-inspections
5. Gas freeing and purging
6. Chemical flushing and waste disposal
7. Production interruptions and schedule delays
These indirect costs frequently exceed the cost of the joint itself, particularly in offshore facilities, shipyards, refineries, and operating plants.
Industry Validation
A separate shipyard installation study involving 394 Pyplok® fittings reported:
Approximately 890 man-hours saved
89% reduction in labour hours
65% overall installed-cost savings
Although the fitting material cost was higher, the reduction in labour, inspection, and support activities resulted in substantially lower total installed cost.
Conclusion
The study demonstrated that Pyplok® non-welded technology can significantly reduce installation time while maintaining equivalent system performance and pressure integrity. By eliminating many of the activities traditionally associated with welded joints, project teams can improve safety, reduce schedule risk, and achieve meaningful reductions in total installed cost. For offshore, marine, industrial, and hydraulic piping applications, the findings confirm that the largest savings are often achieved not through lower material costs, but through reduced labour, inspection, and project execution requirements.
