TDW facilitates safety valve and pipeline replacement in France for GDF SUEZ

T.D. Williamson (TDW), a leading supplier of pipeline services and equipment, has announced that it has successfully performed a hot tap and plugging intervention on a gas distribution pipeline in Toulouse, France for GrDF, a subsidiary of GDF SUEZ that operates the gas distribution network in France.

GrDF Toulouse retained TDW to replace a single safety valve on its ND 300 gas line. Following the preliminary feasibility study, it was revealed that the valve was situated in very close proximity to two additional valves on pipeline ND 150.

TDW recommended that all three valves be replaced at once, allowing GrDF Toulouse to save time and money in future maintenance on the additional valves. Proper function of these valves is integral to GrDF Toulouse ensuring public safety, as they enable the company to quickly halt gas flow in case of emergency. GrDF Toulouse agreed that replacing all three valves was the best approach.

Excavation works halted by travelling group

On the day excavation was to begin, a large number of travelers on their way to Southern Europe converged on the GrDF Toulouse jobsite. The group camped on the property for several days, halting all progress.

Completing the maintenance on schedule and returning the line to full operating pressure was vital to GrDF Toulouse, as on the day following completion, GrDF Toulouse was committed to supply gas to a major aircraft manufacturer. GrDF Toulouse's customer required the gas to operate its co-generation plant, responsible for producing the electricity necessary to power its jetliner manufacturing units at its St. Eloi facility in Toulouse.

Project gets back on track, only to face corrosion surprise

After several days, the travelers finally left the jobsite and – being very cognizant of GrDF Toulouse’s impending deadline – TDW commenced work immediately.

The first phase was to excavate the line, which was achieved quickly and safely, despite the existence of several high voltage cables in the area. However, the TDW team soon ran into its next critical challenge – a section of the primary pipeline, ND 300, was completely corroded and had to be replaced before the new valve could be installed. More complications meant more time.

Determined to help GrDF Toulouse meet its commitment, TDW adjusted its plan by enlarging the excavation by 13.12 ft (4 m), exposing all of the corroded area.

Hot tapping and plugging operations

To isolate the affected section of line while maintenance work took place, TDW carried out a series of hot tap and plugging operations using its T-203 and T-101 tapping machines and SHORTSTOPP® 275 and 500 plugging machines. The intervention was conducted at the service pressure of 17 bar (246 psi) – reduced from 25 bar (362 psi) – which was necessary to operate the tapping machines.

Project completed on time

Much to the relief of GrDF Toulouse, TDW was able to replace, on time, the damaged pipe and all three safety valves. Service pressure was returned to 25 bar, allowing GrDF Toulouse to transmit the gas to its customer’s co-generation plant.

“We are very pleased that the solution we developed for GrDF Toulouse saved them the time and expense of replacing the two additional valves at a later time,” said Patrick Piroth, Project Manager – Hot Tap & Plugging Services for TDW. “That we were able to carry out the interventions, in spite of the unforeseen delay, is extremely satisfying. We are glad that we made it possible for GrDF Toulouse to fulfill its commitment to its customer,” he added.

"It was a difficult job. We are really impressed by the determination with which TDW worked throughout the entire project, which they completed to our greatest satisfaction,” said Michel Robert, Project Manager - Steel Pipelines for GrDF Toulouse. “We did not believe that the schedule could be met, but TDW did it. Thanks to their expert recommendations, we now have a completely renewed valve system, and the faulty pipeline section has been replaced. It was a clean and perfect job. This section of our network is now fully secured, and in full compliance with the French legislation that requires that we must be able to shut down our network in less than 15 minutes. Safety is, and remains, our priority,” he added.

Adapted from press release by Elizabeth Corner.

Read the article online at: https://www.worldpipelines.com/business-news/15072013/tdw_performs_safety_valve_and_pipeline_replacement_in_france_for_gdf_suez_389/