A Powerful Case For Infrared Windows
EP Editorial Staff | November 10, 2010
See what you’ve missed! Numbers based on the real-world experience of a power-gen facility show significant ROI.
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 insurance carrier had already done the necessary research and determined that the power plant could achieve a reduction in hazard liability and maintenance costs through the use of infrared windows. Benefits included:
- Utilization of IR windows for routine inspections of healthy equipment did not require the elevated levels of PPE required in 70E, since, as stated in 70E 100: “Under normal operating conditions, enclosed energized equipment that has been properly installed and maintained is not likely to pose an arc flash hazard.”
- Maintaining an “enclosed” state for the switchgear, motor control center (MCC), transformer, etc., maintains energized components and circuit parts in a “guarded” condition, in NFPA terms. Therefore, the hazard/risk category would be equal to reading a panel meter, using a visual inspection pane for lockout/tagout confirmations or walking past enclosed, energized equipment—and the inspection could even be conducted during peak hours for best diagnostic data.
- Use of IR windows would eliminate the need for a supporting cast of electricians to remove and reinstall panel covers, as well as allow critical personnel to be available for other tasks that were often being outsourced.
- The ability to perform more frequent inspections of critical or suspect applications would help ensure plant uptime while at the same time reduce insurance liabilities.
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.
- In accordance with NFPA 70E and OSHA mandates for energized work, the entire inspection team dressed in 40 Cal/cm2 PPE (personal protective equipment). Team members spent an average of 30 minutes to suit-up and dress-down—twice a day. This was a total of 57 hours related to PPE over a 19-day cycle.
- The thermographer spent 117.6 hours simply waiting for panel covers to be opened/closed to provide him access.
- The electricians spent 58.8 hours (29.4 hours x two men) waiting for the thermographer to complete his work once the panels were removed.
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:
- Total man-hours per inspection of “inspectable” equipment: 497.7 hours (19 days)
- Staff electrician internal charge-out rate: $62 per hour
- Contract thermographer charge-out rate: $150 per hour
- PPE suit-up twice daily, per man (30 minutes per man, per suit-up)
- 48 minutes per compartment panel for safe removal, refitting (per man for a two-man team)
- 12 minutes per panel for infrared scan
- 147 individual panels to inspect (see Table II)
The benefits of IR windows…
In his investigation of the technology, the power-generator’s corporate reliability engineer determined that IR windows:
- Would provide non-intrusive access to electrical applications. Surveys could be conducted during periods of peak-load without elevating risk to either plant assets or processes.
- Would eliminate the need for a supporting cast of electricians to remove and reinstall panel covers. These critical personnel would then be available to perform other tasks which were often being outsourced.
- Would eliminate high-risk tasks during inspections (through closed-panel inspection), thus increasing safety for thermographers.
- Would not require the elevated PPE levels mandated in 70E (for routine healthy-equipment inspection), since 70E 100 notes: “Under normal operating conditions, enclosed energized equipment that has been properly installed and maintained is not likely to pose an arc flash hazard.”
- Would, in NFPA terms, maintain electrical equipment in an “enclosed” state and maintain energized components and circuit parts in a “guarded” condition. Thus, the hazard/risk category would be equivalent to reading a panel meter, using a visual inspection pane for lockout/tagout confirmation or walking past enclosed, energized equipment.
- Would improve inspection efficiency. It also would allow increased inspection frequency for mission-critical or suspect applications.
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:
- Increasing safety
- Facilitating the inspection of previously “uninspectable” equipment
- Increasing the frequency of inspection—while at the same time saving money
- Safeguarding profitability by eliminating high-risk behavior that posed a risk to plant assets and production
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