When the return to operations of a midstream natural gas treatment facility was delayed beyond its planned turnaround timeline, the cost of legacy flange bolting methods became palpable. The facility was required to halt its startup when multiple bolted flange joints were discovered to be leaking. To remedy the urgent situation, 32 additional skilled field technicians were sent to independently confirm that every joint within the facility was ready prior to another startup attempt. After an additional 11 days of downtime, the project's original justification was in question. Could this have been prevented, and what were the problems?
Nuanced issues were discovered by the emergency technicians, and all of them were well documented for post-analysis and improvement. But it was the simplest issue that affected the loss in the most impactful way. The joints identified as installed to less than 20 percent of their targeted stud stress could easily be the justification for the extra shutdown. What made the joints left in their fit-up condition so egregious was that they had also completed sign-off tags from the first installation hanging with their post-audit reports.
Thanks to DuraSquirt® DTIs, facilities completed their work three days ahead of the engineering plan.
Many other issues that were identified in post were less singularly offensive, but all shared common systemic issues tied to torque. When tallied up, the simple use of torque was identified as the second-most influential reason for the unexpected shutdown. When you consider that jobsite fasteners will inevitably be a mix of new, re-used, coated, stainless, lubricated, corroded, damaged, and unified coarse (UNC) threads versus UN8, etc., and multiply that by the mix and condition of the tools used along with the individual procedural differences, it is plain to see how the selection of torque from a reference table may not be representative of all real-world applications. When not dutifully selected for the specific, unplanned conditions that may be encountered, torque can result in unexpected forces contributing to further closure issues.
The answer to reducing the reliance on torque and preventing egregious oversight was the midstream operator's straightforward request for Applied Bolting Technology Products LLC. The one significant caveat was to expect the incongruity of an active jobsite to be omnipresent. By implication, the operator requested Applied Bolting to strive for simplifying the system or else risk additional jobsite paralysis by needing to push fine details out to field personnel who were previously unfamiliar with them.
The solution was to adapt a piece of construction technology from the structural bolting world in a way that harmoniously impacted all three objectives. The application of a direct tension indicator (DTI) eliminated the risks associated with the blind use of torque on bolted flange joints by simply providing feedback to the installer that the designer's targeted tension was achieved, despite the typical jobsite flux. The DTI was calibrated to indicate stud stress with an indelible visual mark that enables multiple conformance observations to mitigate oversight errors.
With the success of reducing the systemic reliance on torque, an improved technique with kitted DuraSquirt® DTIs for each flange that applies the elastic interaction compensation techniques was implemented for use during the next two facilities' scheduled turnarounds. The goal was to build on the benefits realized with the use of target-stress indicating DuraSquirt DTIs and reduce the installation time and effort, which would also increase worker safety.
Thanks to the DuraSquirt DTIs, both facilities completed their work three days ahead of the engineering plan, attributing this achievement to the 80-percent time and effort savings per joint realized with the single-pass DTI kits. The reduced-input effort maintained 100-percent observable conformance, and each facility returned to operation without additional safety or startup issues.
Contact Applied Bolting today to find out how its full line of DTI products can help your facility lower costs by reducing installation complexity without sacrificing your time, quality or worker safety objectives.
For more information, visit www.appliedbolting.com or call (800) 552-1999.
