Holdfast Training Services Trial Blog

Design

The remainder of the GRP pipe line was installed by York Civil, using GRP with flexible coupling free issued by John Holland. The design showed that the pipeline would transition from a flexible pipe (i.e. the use of couplers and concrete thrust blocks) to a rigid pipe (i.e. fully welded) at the interface between GO scope of works. Originally GO were to supply all of their own GRP for the reminder of the underground and the above ground piping that leads to the pumps. However our procurement spotted a potential opportunity and decided to use the surplus GRP we had onsite to free issue to GO instead. This all happened during the tender stage, about three months ago.

Flexible GRP Pipe Installation.

Above Ground Rigid Pipe

Issue 1

After arriving on site GO began some other packages of work and provided spool drawings for the GRP they were supplying for approval. During the design of this GRP the manufactures passed the design to a consultant for ratification. The consultant identified significant issues with the longitudinal strength of the pipe, which had been designed using the specification supplied by our designers (KBR). After this several discussions ensued on site between myself and GO, it became apparent that we had become messengers between the two technical experts (one in KBR and the other in the consultants) who had differing opinions. Eventually I was able to arrange for them to get in the same room and thrash the problem out. The final outcome was that the pipe needed to be upgrade at a cost of $45,000 to deal with the additional longitudinal strength. These longitudinal forces were due to the operation of the pumps and thermal expansion. KBR were able to argue the fact that there was enough information on the drawings for subcontractor to know this and even though GO were on a supply and install contract they had a duty to do some design. Luckily in the same meeting KBR were able to muddy the waters to such an extent over who was responsible for these changes that GO accepted the cost, rather than try and challenge it.

Issue 2

About a week after the above issue was resolved I received a separate email from KBR asking that I check the GRP we were free issuing to GO as there may also be issues with that. After speaking to the GRP supplier it became clear that the pipe would not be suitable for the current design. The design was then changed to switch the section of pipeline back to a flexible. With John Holland receiving a bill for the redesign and a $20,000 variation from GO, with further changes to the design expected this will rise. My role on site has been to manage this process and try to ensure design changes have minimal impact on the work already completed. The cause of this issue could easily be passed back to the procurement team for not checking the pipe would be suitable, however I think it goes deeper than that. The designers were aware of the plan to use the GRP but didn’t comment until GO raised the issue above. In addition the suppliers of the pipe had previously agreed it would be suitable without actually understanding the full design.  Unfortunately it looks like cost of all these variations is likely to come to John Holland. Although I have already been tasked with trying to pin this on the designers.

Issue 3

The more worrying issue was the fact that the same free issued GRP was used at the other end of the pipeline where it discharges into the lagoon. The pipe was wrapped to make it rigid, as shown on the drawing and using the wrapping methodology provided by the pipe supplier. Once installed the pipe was hydrostatically tested to 625kPa, a value given by the designers in answer to an RFI just a week earlier. Two days after conducting the test we received a further email from KBR requesting that we not test the pipe as it would fail under the pressure. Luckily the test went fine but the potential for injury was there and as such this has been raised as an incident within the John Holland system. Operationally the designers see no issues with the pipe as it currently is. The pipe is positioned 5km away from the pumps and is open ended so the pressure is deemed to be negligible.

Seawater Inlet Pipe

Conclusions

The design of GRP for pipelines is a specialist area in its own right. In the case of the site at Sundrop Farm it was clear that the designers at KBR were not fully aware of what they were doing in relation to the GRP design. The design and associated documents had a number of flaws which had they been scrutinised by a specialist would have been picked up much earlier, which in turn would have reduced the financial impact of the changes we are now having to manage on site.

With regards to procuring items the supplier needs to know as much information about the environment, system and operating conditions their component will operate in. Had the GRP suppliers understood the full system and operating conditions of this design they would have been able to provide more suitable product capable of operating as designed and reducing the impact of future changes. Instead they were responding to isolated RFI’s from the procurement team, thus providing answers which were not relevant to the situation.

From a site point of view it is difficult to see how we could have responded differently. We were provided with IFC drawings from the designers and pipe procured by our procurement team. The designs go through a review process both by the designers and John Holland. Had it not been for the subcontractor conducting a review of the GRP and us responding to the information they provided the installation would have continued as per the design. The impact of this is hard to quantify, the plant could have operated as designed for years or the GRP could have failed as soon as the plant was switched on.

In other news

I took a long weekend off earlier this month and took the opportunity to drive up to Uluru or Ayers Rock. The drive takes about 12 hours through the outback and is broken up with nothing apart from a missile testing range, the odd service station and Coober Pedy. To break up the journey we stopped at all of these and spent the night at Coober Pedy. The town’s main claim to fame was the discovery of opals in 1915. Troops returning from the First World War began to settle in the area from this date. Because of the harsh climatic conditions the settlers began to tunnel into the rock and build homes (called dug outs) underground.

Wilfred Pointing to His Christmas Present

Today the town has a population of almost 1700 and most of the towns building remain underground. The hotel we stayed in the temperature remained between 22 and 25 degrees all year round without the need for air conditioning, despite outside temperatures exceeding 40 degrees for much of the year. Natural ventilation is provided by a number of shafts that extend from each of room to the surface above. Each room had an umbrella positioned upside down under the shaft in the corner to catch dust landing on the floor. The wiring throughout the hotel was done by drilling horizontally, then using a vacuum to suck a piece of tissue with a piece of cotton attached and then pulling the cables through.

The Comfort Hotel Coober Pedy