ARNOLD AIR FORCE BASE, Tenn. -- When a prime opportunity to complete a considerable undertaking at Arnold Air Force Base recently presented itself, planners and craft personnel seized it.
The decision to proceed with the removal of thousands of feet of insulation during a brief outage and the efforts of crews to quickly get the job done resulted in tens of thousands of dollars being saved on the project.
Outer insulation on a pair of air lines that run from the von Kármán Gas Dynamic Facility to the 16-foot transonic wind tunnel, also known as 16T, in the Propulsion Wind Tunnel area needed to be cleared so that General Physics, the onsite inspector at Arnold, could get a clearer look at the lines for an upcoming assessment.
Each line is around 1,240 linear feet in length, meaning around 2,500 feet of insulation would need to be removed. A portion of each line is accessible from the ground level, but a significant section of each is situated off the ground, as high as 30 feet up.
The two lines are used to transport high-pressure air, or HPA, to test facilities. Chris Broadrick, Work Control supervisor with the Test Operations and Sustainment contractor at Arnold AFB, described high-pressure air as a “high commodity,” as it is necessary for much of the testing that occurs at Arnold.
While these lines are energized, meaning HPA is flowing through them, the use of mechanized equipment within 10 feet of them is prohibited. This meant that the use of motorized aerial work platforms to reach the higher portions of the lines would be greatly inhibited.
Daniel Flanigan, Flight Investments project manager for the TOS contractor, was charged with facilitating the removal of the insulation for the inspection. He reached out to Broadrick, and the two discussed how to approach the task.
Broadrick developed a plan to complete the project. He estimated that it would take around four weeks for a four-man crew to remove the insulation since they would need to work around the HPA outages when using aerial work platforms.
“Getting high-pressure air outages is really tough due to the test load that we have,” Flanigan said.
Broadrick and Flanigan came up with an alternate plan. The four-man crew removed all the insulation they could while working on the ground and from a 10-foot stepladder. This got the project off to a good start, but a substantial amount of insulation remained on the portions of the lines located more than 10-feet off the ground.
Although the Carpenter Shop at Arnold constructs scaffolding for various projects around base, Flanigan and Broadrick discussed the prospect of renting scaffolding to accomplish the remaining removal due to the scale of the job. Unlike the aerial work platforms, scaffolding is not mechanized. This would allow crews to work on the insulation removal while the HPA lines are energized.
It was determined that 200 linear feet of scaffolding would be needed to complete the project. The cost to rent this amount of scaffolding would be more than $5,000. There would also be additional charges to both erect and dismantle the platforms of around $14,000 and $9,600, respectively. Because assembly and disassembly would be required in at least three different locations, these costs would have totaled approximately $72,000.
“Once we really got to looking at it, scaffolding, to me, was not cost-effective if we could get an outage to be up there around that stuff with an aerial work platform,” Broadrick said.
Broadrick suggested that rather than pursuing the costly scaffolding rental, those tasked with the insulation removal should look for an HPA outage to complete as much of the work as possible utilizing aerial work platforms.
They soon got this chance. The Tactical Integration Group, which reviews AEDC test and maintenance schedules, determined that the compressors used to produce HPA at Arnold were in need of preventative maintenance. The compressors would be offline for four days, providing the insulation removal crew with a small window to finish the job.
The four-man team called for in Broadrick’s original plan was expanded to around 20 to include crews from various craft groups, and four aerial work platforms were borrowed. Although the new approach would create a tighter window for completion than originally projected, the increase in manpower and application of the powered platforms allowed for the expeditious removal of the insulation.
Work began on the morning of Jan. 14 and, by the afternoon of Jan. 17, all of the insulation had been removed except for around 30 linear feet behind the 16T facility that could not be reached with an aerial work platform.
“They understood the importance of getting this done while we had this four-day window because we’re not sure when there will be another high-pressure air outage because high-pressure air is such a commodity,” Broadrick said.
According to estimates, opting to wait for the outage to use aerial work platforms saved more than $75,000 on the job.
“It’s saved us a lot of money,” Flanigan said. “Plus, it’s reduced the amount of downtime that we needed.”
Broadrick said because only a small amount of insulation remains, the Arnold AFB Carpenter Shop will construct scaffolding for its removal.
However, more than enough was removed for examination of the lines. Several inspectors from General Physics worked the same shifts as the craft crews to follow with their inspections once the insulation was extracted.
Broadrick said the insulation will not be reinstalled, as it had been determined previously that it is not necessary for operation of the HPA lines.
Flanigan said despite working long shifts over the weekend in 30-degree weather, the crews assigned to the insulation removal met the challenges, worked efficiently and remained diligent. He added he was glad to have them on the job.
“I think we have very dedicated crews at AEDC, and they were committed to getting this done within the time we gave them,” Flanigan said.
Craft personnel assigned to the job were: Caleb Thomasson, Robert Porter and Samuel Anderson from the electrical crew; Andy Riis, Paul Gallagher, Chris Cleek, Dominic Marzacola, Brandon O’Neal, Casey Griffith, Chris Easterly, Steven Overturf, Joseph Todd, Timothy Finch, Danny Smart and William “Wolfie” Mount from the sheet metal, ironworker and laborer crew; and Dane Barstad, Justin McNeese, Charles Gentry, Shannon Medley and Bart England from the Pressure and Hazardous Material System and Metallurgical/non-Destructive Testing Lab crew.