Installation of a 250mm intermediate pressure ball valve

Installation of a 250mm2

Key Facts

  • Project: Install 250NB valve to the IP truck main Wellington CBD
  • Client: Power Co NZ
  • Location: Jervois Quay, Wellington, NZ
  • Contract Value: $200,000

The project was originally awarded to Siemens Energy Services in August 2010, and with the subsequent sale of Siemens contract to Electrix in April 2011, the project was transferred to Electrix for completion in May 2011.

As part of the capital FY 2010 - 2011 works program for Powerco it was deemed necessary to install another intermediate pressure network isolation valve adjacent to Queens Wharf, Wellington City. The installation of a sector valve, immediately up stream of the Queens Wharf DPRS allows for the isolation of the IP pipeline, should a failure occur beyond the proposed valve whilst maintaining supply to critical installations such as the Tory Street DPRS and Queens Wharf DPRS. Isolation of the network at that point would ensure supply is maintained to the Wellington CBD.

The entire operation was project managed by the Electrix Wellington office with the assistance of technical expertise from Electrix Albany and Palmerston North offices. Prefabrication welding of the valve assembly and the civil component of the work were subcontracted to local companies.

On site construction started on the 5th of May 2011, comprising the excavation of the existing IP pipe line and the area where the valve assembly would eventually be located. Live welding of the pipe line commenced on the 6th with fabrication completed on the 7th. Drilling and flow stopping by Electrix staff using specialised equipment was then carried out over the next two days to liven the new section of line containing the ball valve and to cut and cap the existing pipe line allowing the flow of uninterrupted gas through the new valve assembly.

Despite the long hours worked by the team to carry out the valve installation safely, without interruption to the essential gas supplies, and to a very high standard over a period of 4 days the job was a complete success and all site works were completed in the time constraints.

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