The insurance carrier of a regional power-generation facility asked the company to perform regular preventive maintenance on the switchgear within its operations. Unfortunately, regular downtime was not a practical option for the power plant, as the processes required to do the live inspections were hazardous and required more manpower and resources than the facility could provide. Management began to seriously re-think its strategy: In light of NFPA 70E, inspections of energized equipment were becoming more restrictive, more time-consuming and more costly.What had not been seen
The overall focus was to facilitate inspection of the primary switchgear in the facility's electrical distribution system and several smaller operations within the plant. An impending shutdown increased the sense of urgency, since all Phase I installation could be fitted during that period.
IRISS performed an on-site inspection to ascertain the optimal position and quantity of windows that would give thermographers thorough visibility of desired targets. It found that none of the primary switchgear or transformers had been included in the site's inspections. The reason: inherent safety hazards associated with their being safely inspected while energized (see Table I). Based on this information, the primary goal of Phase I of the IR window installation was to bring this equipment into the standard inspection routes—and more important, allow the inspections to be conducted in line with NFPA and OSHA safety mandates. A time study was then completed, detailing the man-hours and the costs involved in completing Phase I.
Typical cost analysis of traditional inspection...
The power-gen facility had previously been using a contract thermography company, with a survey crew made up of two in-house electricians and one contract thermographer. The hourly wrench time (time spent on productive labor) rate for the electrician was calculated at $62, and the contract thermographer's rate was $150 per hour ($1200 a day). Typically, the equipment being considered for Phase I window retrofitting would require 19 days to complete. This translated into 497.7 billable hours (see Table II). Alarmingly, as the task breakdown in Table II also shows, there were a staggering number of unproductive man-hours (94% of the total project time) associated with the standard inspection activities.
Table III details the man-hour costs for the infrared survey using a contract thermographer without IR windows or viewports. The following assumptions are made:
The benefits of IR windows...
In his investigation of the technology, the power-generator's corporate reliability engineer determined that IR windows:
The facility's 95 applications with 147 inspection compartments required 203 infrared inspection windows. The 203 installed IRISS infrared windows represented an investment of $48,841.00, including contract-labor installation time.
The IR-window installation...
The installation of the inspection panes was conducted during a shutdown, using two install teams. The majority of the windows were installed while equipment was de-energized, in what NFPA terms an "electrically safe work condition." Some installations, however, involved energized gear and needed to employ the traditional safety measures such as use of PPE, energized work permits, etc. The work occurred during normal business hours since this allowed more flexibility.
Cost analysis of inspection with IR windows...
With the infrared windows installed, there was no requirement to remove panels or wear increased levels of PPE. In addition, inspections could now be performed on their applications that had previously been considered "uninspectable." Finally, the entire task became a one-person job.
These IR windows also increased efficiency and economy-of-motion. Total personnel-hours to complete an inspection dropped to just 33. As a result, plant surveys of equipment dropped from a cost of almost $45,484 to just under $4950 (see Table IV). Because of these efficiencies, the facility now spends $40,534 less per inspection than it did prior to the installation of the windows—translating into a savings of more than 90%.
Calculating return on investment
Table V combines data from previous tables to illustrate the return on investment (ROI) that the power plant realized from Phase I of its infrared window program. This information details the total investment using two scenarios: 1) traditional open-panel inspections with a contract thermographer and two staff electricians; and 2) the same contractor using IR windows.
Switching to the windows was shown to pay dividends in just two inspection cycles—producing more than $33,227 in savings that can be put back into the budget by the end of the second cycle. After five inspection cycles, the savings were over $153,829.
Because inspections can now be completed with greater ease and without increased risk to the plant, the personnel and the processes, the operation increased the frequency to a quarterly basis, reflecting best-practice recommendations that originally were not considered feasible.
The new inspection process using infrared windows brought substantial ROI to the plant in just two inspection cycles, while reducing the risk of catastrophic failure of the site's critical power-distribution systems. Management succeeded in:
In the future, the facility plans to buy its own IR camera and provide training for its maintenance engineers—which should quickly pay dividends and allow the plant to improve its maintenance program, all while operating in full compliance with the requirements of NFPA and OSHA. MT