Case Study – Replacing Galvanized and Plastic Gas Services in San Bernardino and Perris CA, with SoCal (Sempra Utilities) and Kobus 400 Pipe Puller.

September 23rd-24th,2020

Description: After a successful ConExpo 2020 show in Las Vegas, we met with SouthWest Directional who wanted to push our technology within the gas sector in California. Their customer being SoCal has 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.

Whilst we tried to do the trial right after the show, due to C-19, we had to abandon and retake in September.

The trials would comprise two days replacing galvanized ¾” and some sort of ½” plastic in San Bernardino and Perris, CA. In both days we would be replacing with ½” HDPE and tracer cable from the main to the outside meter of the dwelling. The lengths of the galvanized were 40, 50 and 60ft and 50ft for the plastic ones.

The services were on the first day at a depth of 3-3.5ft in a medium hard compacted sandy soil and the second day about 5-6ft deep in extreme conditions of hard compacted and dry soil. It was actually so hard, that it had to be broken with the breaker.

As mentioned above, first day we replaced three services with minimal excavation at main (3x3ft) and meter. As 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 three 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 SoCal, SouthWest Directional and of course Kobus Inc.

The second day saw us heading to a very arid area in Perris replacing ½” plastic which is now becoming brittle and needs replacing. Due to the terrain, pulling was pretty challenging and limited to 50ft sections.

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 (likely to ball up). This is part of the technique which allows the ground to accept the slightly increased diameter of the balled up service.

On the first pull, the cable snaped after 40-45 ft of pulling. Upon inspection and spot digging the area, it was agreed that the roots of a large tree right on top had grown around the service making it impossible to be pulled. Nevertheless, the last 5ft were open trenched and the service connected. The old service as expected had balled up but it was progressing well until the root came to play. The new service towed in was checked for damage and it was flawless; no scoring and no gauges.

The second pull of also 50ft was successful and pulled well. SoCal insisted on an intermediate small pit to see the effects of the old service balling up. The result was good as its diameter was only slightly bigger than the expander already fitted to our Kobus Pulling cable.

Excavator used: John Deere 35G

Outcome: Whilst running trials, 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. There was no training during these two days, but instead we answered all the commercial and technical questions from SouthWest Directional and the 20+ witnesses from SoCal. Training is something we will impart should the customer decided to proceed with the purchase of the KPP400 and the crews will gain mastery with time and continuous use of  the Pipe Puller. The crews from SWD and SoCal were outstanding, giving invaluable support and advise to our Engineer.

Over the trial period, we experienced no set backs, one 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 many SWD and SoCal employees on the innovation and Operations areas who were very impressed by what the saw over the two days. Our understanding is that they are in progress to document the machine and follow up with another trial session in the coming weeks to get internal approval and subsequent deployment to their crews.

Author: Tom Atienza (Kobus Inc – VP Operations) -October 2020

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