Bolting specifications and flange management have come and long way in 20 years, and sound leak presentation has evolved through better bolting practices.
A historical perspective
I remember working a local shutdown in 1994 for what is now Canada’s largest energy company, and there were 58 critical connections to manage.
These were hydraulically tensioned reactor goosenecks or hydraulically torqued high-pressure heat exchangers — both backed up with ultrasonic bolt-load elongation verification, flange completion, and ultrasonic testing and reporting turnover packages.
Enhanced, modern connections
Fast forward to a major construction upgrade in 2000: Near completion, the engineering procurement and construction (EPC) contractor realized that a bolting plan was necessary to ensure a leak-free startup. We helped the contractor write a comprehensive flange-management plan. I say “helped,” but we wrote it and they reviewed, commented on changes, and approved. In the end, the plan managed 10,750 flanges, which all started up leak-free.
A big jump from those 58 critical connections just 6 years earlier.
Since 2000, facility owners implementing bolting specifications and flange management plans have progressed in momentum at record pace. Many have realized great success, but most have also struggled with some aspects, depending on whether engineered specification calculations, quality management, implementation stakeholders, or training guided their development.
The truth is you’re not alone. All these stakeholders need to a sit at the flange management planning table.
Issues in the field
Over the years, I’ve consulted with a wide variety of clients who’ve experienced setbacks. Here are a few examples (without naming names):
- Pipeline consultants called me needing help. They hydraulically torqued an entire pumping station, and it was leaking like a sieve. I asked to see their bolting specifications, and the stresses were in an acceptable range of 50% of yield. Then I asked to see the torque values and found the problem. While the spec asked for 50% of bolt stress yield, they were calculating torque using the thread lubricate friction coefficient of only around 6%.The torque was bringing the studs to less than one-third of the stated bolt stress. Over the next few months, I had to prove using UT what the appropriate K, or nut factor, needed to be to achieve 50% of yield. This had been a long-standing problem. Engineering issues, torque specs, and field execution followed it, but it always leaked. The field teams achieved leak-free flanges with impact wrenches, so personnel formed a cultural belief that torqueing didn’t work but impacting did.
- At a local chemical plant, developers created new construction specifications to achieve a gasket seating stress of 20,000 pounds per square inch. On a significant number of large, 16.46-series A flanges, using double-jacketed gaskets meant bringing the studs to yield and rotating, or yielding, the flange bolt circle. We fortunately spotted the error, convinced the construction team to wait, and got both the gasket specifications and bolt loads changed to something that would work.
The journey continues
Some clients have become fixated on paperwork and getting everyone to sign and initial at every step, making the accountability phase a pencil whipping exercise. Others have gotten confused on where to best utilize UT elongation measurement while still more required all the tool operators be trained, generally by a torque wrench sales organization, and not by people with bolting expertise.
In the last few years, great advances in American Society of Mechanical Engineers (ASME) guidelines have also helped. Much comes from what many bolting contractors have suggested for years, so ASME PCC-1 validates the path we’ve all been on and helps give owners yet to embrace sound flange management a fighting head start.
It’s been a journey for the entire industry and, while it’s had its bumps, we’ve made great progress in general.
Engineers are rigorously analyzing specifications, and they’re starting to get their heads around flange inspection, alignment, and efficient and effective flange reports. Training isn’t quite where it needs to be in Canada but will come as owners focus on the greatest impact in leak-free performance: the person holding the wrench.
That, arguably, is the missing link. We can write specifications, inspect materials and flanges, train employees to use equipment and document everything — but we still see flanges fail. Why? Competency.
Training and competency are not the same thing
Teaching a pipefitter or boilermaker how to operate “brand X” equipment isn’t the same as teaching them foundational bolting principles, requiring a period of supervised experience, and testing procedural practices along the way.
I’ve always seen a huge impactful difference when I spend the time teaching bolting craft before the how.
Developing bolting competency programs and industry standards is the holy grail to truly leverage all the value still hidden in your hard work through developing bolting specification and quality standards.
As we all work toward to building a leak-free workplace, bolting competency needs to be our next leg in the journey.
President and General Manager