Case Study – Replacing Copper and Galvanized Gas Services in Silver Springs MD, with PPS and Kobus 400 Pipe Puller.

March 17th to March 19th 

Description: This case study was prepared with the data obtained whilst training the crews for Precision Pipeline Solutions (PPS), our new customer in the State of Virginia. PPS performs gas service work for Washington Gas. Both have been looking for new trenchless technologies which can save them time and money in certain replacements where due to risk of strikes and other issues associated with other trenchless techniques, made it expensive and time consuming.

It was not possible to insert the ¾” galvanized as it had already been inserted with ½” copper in the past on he first service, and not possible on the second as was a ½” copper service.

The successful three days training was completed from March 17th to March 19th.

The training would comprise two days replacing ½ copper (one turned out to be galvanized ¾”) In both days we would be replacing with ¾ ” HDPE and tracer cable from the main to the outside meter of the dwelling. The lengths of the services were 50 and 60ft respectively.

The services on the first day were at a depth of 3-3.5ft in a medium hard compacted sandy soil and the second day about same depth in wetter conditions and similar soil. These are ideal conditions for successful pipe pulling.

Excavations were kept to a minimum in both cases but since there were other works required, the riser was excavated out, so we pulled all on straight line this time. There were no issues and all pulls were perfect in times of 3 to 3.5 minutes each. Due to the 360° foot rotation of the KPP400, the road was kept open at all times and all health and safety measures where in place by PPS, Washington Gas and Kobus Inc of course.

On both pulls, the speed was reduced to slow, this to ensure the ground would have a degree of “giving” as the old service pulls out. This is part of the technique which allows the ground to give and let go services which have been buried for decades. Once the service is seen to be moving (ground resistance broken), the rotation on the Pipe Puller was increased to maximum and saw the pipes coming out smoothly in minutes.

The new service towed in was checked for damage and it was flawless; no scoring and no gauges. 

Excavator used: CAT 302.5

Outcome: Whilst running training, the management of it on the day relays on Kobus Inc engineers. We ensure that the pulls follow the client’s H&S rules as well as our own company policies. During the sessions (which are hands-on from the beginning) we answered all the commercial and technical questions from PPS and Washington Gas personnel who witnessed the smoothness and safety of our Technology. Training is something we always impart to new customers, but only by continuous use afterwards, they will gain mastery in the use of the Pipe Puller. The crew from PPS was outstanding, giving invaluable support and advise to our Engineer.

Over the trial period, we experienced no setbacks, no cable failure and no Pipe Puller issues. No strikes with neighboring utilities were recorded either. Trials were carried out by certified Kobus Inc Personnel with ample experience on the Pipe Puller and technique, ensuring safety standards were always in place .

Feed back: We met with PPS and Washington Gas personnel on the innovation and Operations areas who were very impressed by what the saw over the two days. Our understanding is that they will progress our technology and make other contractors aware of its advantages over other trenchless (and non-trenchless) methods.

Author: Tom Atienza (Kobus Inc – VP Operations) – March 2021

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