The project was an installation of a new section of a water main underneath a railway line. To ensure continued supply of water while the existing main line was replaced, a temporary 250mm PE bypass to the existing main was also required.
Using a PLASSON Large Bore Saddle and hot tapping tool, the hot tap was performed on the existing 500mm PN16 PE pipe while still under pressure.
PLASSON is the only supplier that offers a complete system which includes the Saddle, Hot Tapping Tool, Clamping Tool and Core Cutter.
This hot tap allowed the main to remain running, and water supply to the town was ensured during installation.
The installation into the existing main was underneath the water table, so continuous pumping was needed to conduct the weld and perform the hot tap. The PLASSON Large Bore Saddle 500-630mm x 250mm was installed in place with minimal digging and required only lightweight equipment.
A Weld Integrity Test port is incorporated into the PLASSON Large Bore Saddle to enable a pressure test before cutting into the pipe.
The Clamping Tool also leaves a mark on the saddle to show if the correct clamp has been used at the correct tension. A Tension Force Indicator (TFI) is built into the strap mechanism – larger saddle sizes
are tightened with a torque wrench.
The unique design of the PLASSON Large Bore Saddle means the weld extends into the area of highest stress in the saddle. This reinforces this area of potential weakness, increasing the strength of the weld and ensuring a long life span.
The job was completed in 1.5 days. On day one, the saddle was installed on the pipe and pressure tested. On day two, the live
tapping was performed.