Case Study

Initial Situation
During the construction of a new section of water main for the local water authority Polyethene pipeline installer, KenKar Plastics were asked to connect a bypass line to the existing main to ensure continuous water supply to the residents. It required the installation of a Plasson large bore electrofusion saddle onto the existing polyethylene mainline that could then be live tapped to connect the temporary bypass line. 

The project was completed successfully by using Plasson’s new range of large bore saddles and live tapping tools (Hot Tapping). The project site was on a section where the pipeline crossed underneath a railway line. This made the installation conditions extra challenging due to restricted access to the saddle installation site. The saddle was successfully welded to the pipe, and a live large bore DN250 connection was drilled into the pipe and an isolation valve installed. The project was completed on time and to specification.

Task
Plasson was asked by KenKar to present a solution to perform simple and reliable live tapping. 
For this line stopping job, KenKar Plastics were looking for:

Solution
To perform hot tapping Plasson is the only supplier that can offer a complete system which includes the saddle, hot tapping tool and profile clamping tool. Given the technological advantages of hot tapping, the main was still running, and the water supply to the town was ensured for the entire time.

The installation into the existing main was underneath the water table, so continuous pumping was necessary to be able to conduct the weld and perform the hot tapping. The Plasson Large Bore Saddle 630-500mm x 250mm was installed in place with minimal digging and 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 leaves a mark on the saddle to show if the correct sized clamps have been used at the correct tension. A Tension Force Indicator (TFI) is built into the strap mechanism – larger sizes are tightened with a torque wrench. The unique design of the Plasson Large Bore Saddle increases the weld zone past the area of the highest stress, which ensures a good weld to the extremity of the fitting. The weak point of the weld is removed and therefore, leads to increased durability under hard operating conditions.

The entire job was completed within 1.5 days. On the first day, the saddle was put on the pipe, and the pressure test was executed; on the second day, the live tapping was performed. Long-term functionality and pipe bonding are guaranteed. The saddle is used as a hydrant point.

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