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Gas and Water Flow Stopping Services | CDS Pipe Services

Our flow stopping services are regarded by engineers, as one of the most efficient and cost effective means of pipe isolation and intervention for maintenance programmes.

Like our under pressure drilling service our flow stopping or pipeline intervention capabilities cover almost all major pipeline materials and pressures.

We have Steel, PE, Cast Iron and Ductile Iron intervention capabilities for large diameter low to medium pressure pipes like Iris stops, bag stop and Line Stopping techniques. Our pipeline intervention services consist of

  • Low, Medium, Intermediate, & high pressure pipelines ≤ 7barg gas / 24barg water
  • Fitting of saddles, tees & valves
  • Hot taps (Hot Tapping)
  • Line Stop operations
  • Large diameter bag stop & Iris stop
  • PE Bagstop & squeeze off
  • Gas holder hot taps
  • Foam bag insertion for permanent isolation/abandonment

By utilising pipe service techniques, work can be performed allowing alteration, relocation, extension, addition, repair, replacement, maintenance, or abandonment of pipework without shutdown or interruption of service to critical processes or consumers.

CDS Pipe Services Ltd work to a high degree of proficiency, and provide services on a 24 hour basis, nationwide.

Iris Stop

Iris-Stop is a method of carrying out flow stopping operations to facilitate maintenance or repair to 2Bar distribution networks, whilst maintaining continuity of supply.

Developed by British Gas, Iris-Stop has been fully tested and in constant use since its introduction in 1972, and though it is now less commonly used, and only at lower pressures, it has proved itself to be safe, quick and economic method.

The System is used on low/medium pressure gas pipelines, accessed via small hole principle, associated with low-pressure bagging-off operations. The “Iris” is a mechanically operated shutter, which is inserted through a small hole in the main and opened, providing the structural barrier across the pipe cross section. The seal is created by inserting a bag through a similar small hole, positioned on the pressure side on the Iris. Once the operation has been completed, the equipment is removed and the small holes in the pipe plugged.

Line Stop

Line Stop is a method using temporary pipe plugging device for gas or water (other fuels) which provides an economical, effective way to provide a working seal, under line pressure, without shutdown.

Line stopping is isolating a live pipeline, which when utilising a bypass, can be done without the interruption to supplies. This is achieved by inserting a plugging device to shut off the flow.

There may be several reasons why a pipeline may need isolating from pipe replacement or pipe repair to adding new valves or extensions for water or gas distribution systems.

It can be used to isolate pipe sections for repairs, additions or replacements, to relocate or extend lines, and to tie in new lines, all without interrupting flow.

Bag Stop

The Bagging-off Equipment utilises the base of the Tee set Drilling Machine to provides a safe and Comprehensive method of flow-stopping.

Stopping off PE (125mm to 600mm), ferrous 3″ to 900mm live gas mains under gas free working conditions.

The Bagstop equipment comprises a Canopy enclosing the Bagtube which is mounted on the drill set base, enabling a Bag to be inserted through a tapping in to the main and inflated to stop the flow of gas. Sets of interchangeable Noses and Shoes permit the Bag to be correctly positioned relative to the centre line of the main.

Positive support of the inflated Stopper Bag against the gas pressure is provided by the Nose and Shoe assembly. By utilising the base of the Drilling Machine, this equipment enables a temporary flow of gas/bypass, to be provided around a section of polyethylene or ferrous main which is undergoing maintenance or repair.

In the event of Stopper Bag failure, replacement is simple, quick and safe. The equipment provides the means to connect a bypass around a mains maintenance operation subject to the size of the drilled hole allowed by regulations. Flexible “Riders” are available for low pressure applications.

Need Help or Advice?

Our team of specialists are on hand Monday to Friday 8:30am until 5:30pm to answer any questions you have regarding the services we provide.