Infrared program saves time and money, team awarded for efforts

  • Published
  • By Janaé Daniels
  • AEDC/PA
Arnold Air Force Base , Tenn. --  The need for improving inspection processes has been a focus of many Arnold Engineering Development Center (AEDC) departments for years. 

Arnold's response to this effort resulted in an award-winning program. 

When the Facilities O&M department was tasked to assess the equipment health of major test facilities, they not only took it on, but made it an Air Force Smart Operations 21 process improvement. 

They installed infrared thermography windows on high voltage electrical components. 

"Infrared inspection of electrical equipment allows equipment health to be determined and down time intervals to be driven more by condition with a maximum time limit," Jennifer Daugherty, condition based maintenance (CBM) engineer for the System Health and Reliability branch, said. "To improve equipment health assessment and reduce the cost to maintain equipment, we were tasked to improve the infrared program which assesses electrical and mechanical equipment." 

According to Mrs. Daugherty, infrared thermography of high voltage equipment historically has been a costly and lengthy process. 

"Before the infrared windows, thermography required extensive outages and time consuming lock-out/tag-out (LOTO) procedures," she said. 

The first step to infrared of a bolted, high or medium voltage electrical cabinet was to lock out the system, in some cases taking down multiple transformers. Next, the bolted doors would be removed and the area roped off. The locks would then be removed. 

When the equipment was in a steady-state, non-changing condition, infrared thermal images would be collected with an infrared camera. 

At the completion of the infrared imaging, another electrical outage and LOTO was required to bolt the cabinet door back on. The equipment would then be re-energized and returned to normal service. 

"Infrared in the Propulsion WInd Tunnel (PWT) facility took more than 50 locks and three transformer outage to safeguard the breakers for the two 83,000 horse power and two 60,000 horse power motors," Roger Miller, System Health and Reliability electrician said. "With infrared windows we are able to perform this job safely without opening cabinets and performing the extensive LOTO process." 

To date there are more than 100 infrared windows installed around base with 50 plus in PWT alone. 

Mr. Miller is one of 15 trained craftsmen who install the windows and perform infrared thermography. 

"This is a vast improvement over the multi-day LOTO method," Mr. Miller said. "As the benefits of infrared imaging were realized and the cost to attain the data was reduced, we began to schedule and perform the inspection on a quarterly basis, when before it was often the practice to only perform this inspection once every year or two." 

Many lessons have been learned with installation and use of more than 50 thermography windows, Mrs. Daugherty said. 

"Good planning and documentation of the equipment while it is open is the key to good infrared using windows," she said. "Transmission loss through the window must be accounted for and high emissivity targets are key to health evaluation imaging through infrared windows." 

Although the infrared windows are a process improvement, there is still a degree of difficulty. 

"Imaging through infrared windows is difficult," she said. "But, it provides a path toward safer operations and early detection of problems and a high voltage electrical infrared program is more difficult to maintain without these infrared windows." 

For the efforts, the Facilities O&M department was awarded the 2007 best infrared thermal imaging program of the year by Uptime Magazine. 

"This award is well-deserved recognition for Walt Bishop and his CBM team," David Hurst, Reliability Branch manager, said. "The CBM effort has grown significantly over the last few years and we are starting to see the benefits of this team's hard work."