Pipeline Connections

Capabilities

Pipeline and Civil have extensive experience performing cut-ins and connections on various types of water, wastewater and stormwater pipelines. Our clients benefit from our skill and experience in executing time critical technical work. These benefits include less service and traffic disruption, reduced risk of spills, better public perception, strict hygiene compliance, safer planning and execution, and a quality product with the required quality assurance documentation.

Past projects have involved constructing chambers around live gravity sewer pipelines and constructing connections. In some cases, this has involved; installing flow-through moulds to keep chambers live while the chamber is being constructed around the mould, bypass pumping and/or storing flows while work is undertaken. To evaluate the options, we can work with available flow monitoring and modelling data to assess the feasibility of how the work can be safely undertaken

We also have extensive experience making connections to pressure pipelines. Our experience ranges from the smallest pipeline sizes available to CLS 2000 NB water transmission watermains, connections to large live transmission sewer chambers and pump station wet wells.

Our clients can have confidence that when carrying out cut-ins and repairs on watermains we understand the importance of required quality and hygiene practices to protect public health.

Stakeholder management is important to us and we put significant effort into planning to make a connection a positive experience for all interest groups.

Resources

  1. Staff experienced in time critical, carefully planned shutdowns and connections
  2. ASME IX Qualified steel welders 
  3. HDPE welding equipment from 125OD to 1000OD 
  4. Pneumatic sewer plugs up to 1200NB

 

Track Record

This project required careful planning and timing to complete piloting in Campbell Road in Greenlane for service location and pipeline measurements during a low traffic period during Easter weekend.

The modification works were required to take place within school holidays. During the shutdown a section of 470 NB Hunua No.1 was capped off and decommissioned. The tee joining the 630 NB Campbell No.1 to Hunua No.1 was replaced with a CLS bend, welded to the existing pipelines and the abandoned watermain capped off.  Careful measurement and construction of the compound bend and taper prior to shutdown ensured smooth completion of the work within the shutdown window.

This water treatment plant project involved extensions to three concrete mixing tanks to allow for the addition of drain valves. The works also involved in-situ modifications to the existing underground tanks, replacement of large penstock valves, manufacture and installation of pressure vessel tanks, construction of large diameter CLS overflow pipelines, micro tunnelling of concrete pipelines, construction of 7m deep manholes and other mechanical and electrical work.

Undertaking time critical shutdowns of the A and B mixing tanks was a key part of the project.

Innovation was used in the method for making the connections to the B mixing tank – the tank was shut down but not drained, the section of wall was cut out and removed while underwater using divers and pulley systems, this allowed the tank to be returned to service without delay.

The key stakeholder was Watercare Operations. We consulted and communicated with the plant operators extensively throughout the project to ensure operational requirements were always able to be achieved.

For the Northern Interceptor project, we created a weld map to record the serial number of each pipe at each weld. Approximately 750 welds and 46 test welds will be undertaken on the project. 7 staff qualified to undertake the butt welding and 3 staff qualified for large diameter EF welding. 

The project also included welding of stub flanges and the installation of ductile iron fittings at air valve and scour valve chambers. 

On the Glen Eden Trunk Main Sewer Upgrade we fabricated and installed flow‐through moulds around an existing 900NB concrete pipe to allow large diameter benching to be poured in‐situ while maintaining flow through the chamber. This allowed wastewater to be contained, eliminating expensive over pumping, the risk of contamination, the release of hazardous gases and reducing the noise impact on park users.

On the Sunnynook Sewer upgrade we developed a temporary diversion; re‐routing wastewater flows through a manhole. This allowed final cut‐ins to be undertaken without the need for excavation, subsequently reducing impact on park users and avoiding the need for a winter works permit.

As part of the new HDPE Rising Main from Pakuranga to Panmure a live connection was made into the 2.1m diameter Eastern Interceptor tunnel which required a bulkhead to be constructed inside the tunnel.