Line Stopping

Line stopping or line plugging is a solution for isolating a part of a piping system from the rest of the network. All alterations and repairs can be done in the isolated part of the pipeline without service shutdowns for the rest of the network. This process acts as a temporary shut-off valve when the pipeline doesn’t have existing ones nearby or they are not functional.

The line stopping process starts by welding the line stop fittings in place; or if the pipe material cannot be welded or welding is not allowed, a mechanical clamp fitting is used. After the fitting is in place, Tonisco Service will insert the temporary line stop valve and make the cut into the main by hot tapping. After the completion of the hot tap, a mechanical plugging head is inserted into the pipe. The mechanical stopper head is then tightened and the flow in the pipe restricted. Tonisco Service uses mainly mechanical plugs, with high tolerance areas providing a reliable and flexible solution to new and old pipelines regardless of their current condition.

For gas and oil pipelines two basic line stopping operations are Single Stop and Double Stop solutions.

In the Single Stop operation, the line is plugged from one section. After the completion of the plugging, the line is drained and the modification or repair works are done after the line is empty and secured. The line stop works as a temporary shut-off valve.

In the Double Stop method, the line is plugged from two points. The section between the plugging points will be drained while the rest of the network is kept operational with a temporary by-pass between the line stop machines.

Most used applications for line stopping operations are the following:

• Leak repairs with minimum or no service interruptions
• Valve replacements and valve insertions under pressure
• Pipeline relocations without service loss or shutdowns
• Insertions of new pipeline structures/components to an existing system

If you want to know more about the possibilities of making repair and alteration works while keeping your network fully operational, please contact our service team at service@tonisco.com

Key features of Tonisco line stopping Service:

• No need for service interruption
• No gas released into the atmosphere
• No need to wait until the line is completely empty – Reduces the filling time substantially
• Avoids costly redesign of pipeline sections and reduces the cost of planning
• Removes the necessity to notify of heat or cooling shortages
• Co-operation – Sharing of different working stages (welding works)
• Turnkey planning and execution, if needed

Operational parameters – Basic service package:

• Maximum operational pressure 25 bar @ 40°C
• Maximum operational temperature 130°C @ 16 bar
• Line Stop range DN20 (3/4″) to DN1600 (64″)
• Both ASME and DIN Standards apply

Operational parameters – Special service package:

• Maximum operational pressure 700 PSI @ 40ºC
• Maximum operational temperature 270ºC @ 350 PSI
• Line stop range DN25 (1″) to DN1600 (64″)
• Both ASME and DIN Standards apply