“Blackhawk™ engineered products delivers targeted and practical solutions for bolted-assemblies in the energy industry. As a division of INTEGRA Technologies™ we draw on over 30 years of field experience and combine it with our engineering expertise to provide products that deliver certainty of outcome.
In this case study we will focus on a major California refinery which has had over 1 million hours of Pop Washer™ usage. The trial began in 2013 and breakouts have occurred approximately every three months since installation. They have a four-drum delayed Coker unit with an over 50,000 barrel-per-day capacity which cycles from 150 to 900 degrees Fahrenheit every 18 hours. Breakout had traditionally been a pain due to galling issues.
You can see the application here: This is a 30-inch 300 pound flange on the overhead vapor lines. There are four of these and each has 32 two inch bolts. The bolting was fairly typical; B 16 studs at 111,000 pounds bolt load. So 40,000 psi bolt-stress was applied from around 3,500 foot-pounds of torque.
This was a great application for our case study; high cyclic-temperature, large bolts, frequent breakouts, and a history of galling. In terms of scope; we have had over 500 Pop Washer™ activations and over 1 million hours combined total usage. Before the use of the Pop Washer™ they had anywhere from 25% to 75% of the bolts completely seized every breakout. They used the torch to cut them out and had to replace the hardware. The typical process could take them over 12 hours.
This is an on-site video from their disassembly after switching to the Pop Washer™. They haven’t had a single stud-gall, no torches, and all the nuts have spun off by hand it. Now takes 88 minutes to remove all the bolts.
This is an enormous change not just in the time and manpower: it is a completely different process! No longer do they need one crew to torque, one crew to burn through the nuts, clear out the area, hot work permits, and try to schedule this all effectively without knowing the scope of work. Now they know they can send two guys to get the flange ready to go and have the bolts off in 90 minutes.
These are quotes from the maintenance supervisor of the facility, explaining of the process went from four men and twenty-two hours to two men and fewer than eight hours. As a result, manpower has been reduced by 75% and the total reduction in cost has been greater than 85% and the numbers back that up.
Before the Pop Washer™ they spent 1,400 man hours fighting disassembly on these flanges annually. It cost them 56,000 dollars in labor, 19,000 dollars in standby time, and equipment and 51,000 dollars in hardware. With Pop Washer™ total direct costs went from 126,000 down to 13,000 just by eliminating stuck nuts. And this is one application, one type of flange. Imagine how many of these are in the entire plant!
And these are just the numbers that are easiest to calculate, these aren’t even the most important aspects such as safety and scheduling. But it does serve to illustrate the tip of the iceberg of the two main take-home points of this case study; galling is expensive! Really we are fighting the ‘it’s just nuts-and-bolts’ mentality. The fact is, that $100 studs and $50 nuts cost them over 1,400 man-hours and 126,000 dollars in this one application. While that certainly is a significant amount of resources, the bigger concerns are the cascading effects on scheduling and planning and a potential risk of damage and worker safety. We’ve probably all heard the saying ‘an ounce of prevention is worth a pound of cure’. Well, it’s even more so here. First, you can’t allocate resources efficiently if you don’t have certainty of outcome. Second, to combat that: schedule length is increased, so you do end up paying for the problem whether it’s encountered or not. These effects cascade and multiply as time goes on and end up being much more than the direct costs alone. fortunately, galling is preventable! The key point is that there are options and you have to deal with stuck-nuts. Since there are solutions, incurring these costs-delays, risks, and hazardous conditions is a choice.
Basically everyone already has a galling strategy. Unfortunately, many plants choose the most expensive most dangerous and least predictable method which is fighting the problem after it occurs. Preventing it from occurring in the first place is cheaper, safer, faster, and provides certainty of outcome.
If you only take two things away from this presentation, we hope they are these two points: Bolting issues such as galling do have large effects but galling is preventable and prevention is the best option!
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