MRO Magazine

Infrared Inspection Update Saves Big Money

Apaper mill had a very successful infrared inspection program that its managers wanted to expand. However, the requirements of NFPA 70E regulations were causing the US-based mill to rethink its strate...


Machinery and Equipment Maintenance

June 1, 2009
By Martin RoBinson

Industries

Apaper mill had a very successful infrared inspection program that its managers wanted to expand. However, the requirements of NFPA 70E regulations were causing the US-based mill to rethink its strategy, since inspections of energized equipment were becoming more restrictive, more time consuming and more costly.

Furthermore, 8% of the mill’s applications had never been surveyed due to switched interlocks (which automatically de-energize the equipment upon opening, thereby preventing access to energized components), or due to incident energy calculations in excess of 100 cal/sq cm on certain equipment (which exceeds personal protective equipment ratings, and would place personnel in extreme danger and open the company to OSHA fines).

In search of alternative methods of conducting safer, standards-compliant inspections, the corporate reliability engineer investigated how infrared inspection windows (commonly referred to as IR windows, viewports or sightglasses) might be used.

It was determined that:

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• The use of infrared windows for routine inspections of healthy equipment did not require the elevated levels of PPE re- quired 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.”

In NFPA terms, an IR window maintains an ‘enclosed’ state for the switchgear, motor control centre (MCC), transformer, etc., and maintains energized components and circuit parts in a ‘guarded’ condition. Therefore, the hazard/risk category would be equal to that of reading a panel meter, using a visual inspection pane for lockout/ tagout confirmations, or walking past enclosed and energized equipment.

• Use of IR windows or sightglasses would eliminate the need for a supporting cast of electricians to remove and reinstall panel covers. Those critical personnel would then be available to perform other tasks, which were often being outsourced.

• The use of IR windows would provide an efficient method to perform inspections. This would make more frequent inspections feasible for critical or suspect applications to ensure plant uptime.

• The use of IR windows would provide non-intrusive access to electrical applications. Therefore, surveys could be conducted without elevating risk to plant assets and processes, meaning that inspections could be conducted during peak hours for the best diagnostic data.

• The use of IR windows and closed-panel inspection would eliminate high-risk tasks during inspections and thereby increase safety for thermographers.

The focus of the mill’s initiative was to facilitate inspection of the primary switchgear in its electrical distribution system, which feeds one paper machine and several smaller operations within the plant. An impending 10-day shutdown increased the sense of urgency, since all windows could be fitted for one machine during that period.

IRISS Inc. was commissioned by the paper mill, located in South Carolina, to conduct a pre-site inspection to ascertain the optimal position and quantity of windows that would give thermographers thorough visibility of the desired targets. The conclusions from the initial inspection are noted in Table 1.

The customer ordered 200 units of assorted VPFR-75 (3 in. dia.) and VPFR-100 (4 in. dia) infrared inspection windows to complete the installation; 197 windows were later installed at a cost of $42,050. IRISS was also retained to supply a team to perform the installation of the IR windows.

Installation costs (Table 2) were calculated using the following assumptions: A two-person installation team at $6,250 each per day (total cost $1,300 per day) x 10 days = $13,000; $30 per window installation charge x 197 windows = $5,910. The total cost for the project amounted to $60,960.

The installation

Installation of the infrared inspection panes was conducted during three nights and three days during the 10-day shutdown. Some installations were completed on live gear using additional safety measures; however, the vast majority was conducted on de-energized equipment in what NFPA terms an ‘electrically safe work condition.’

Although the plan allowed for 12-hour shifts, installers were quickly and safely moving at a rate of about six window installations per hour, and were finishing the plant on the night shifts within six hours. Installations during normal business hours allowed much more flexibility, therefore all ‘live works’ were completed during these periods.

When the clients’ electricians assisted with the installations, the installation rates were also faster than originally planned (seven to eight windows per hour). All window installations were completed well within the allotted timelines.

Inspection cost analysis

Prior to the installation of the IR windows, all infrared inspections were completed on open, energized gear. Therefore, PPE, live works procedures, risk assessments, permits, etc., were required for all inspections, and as noted earlier, several applications had never been surveyed due to safety restrictions.

The paper mill had previously invested in its own infrared camera and a staff thermographer. The thermographer was trained and qualified to assist in opening panels on energized gear. Therefore, some efficiencies were already in place when compared to a typical crew of a single thermographer and two electricians. Consequently, the man-hour calculations for the traditional inspection are actually conservative.

The man-hour costs for infrared surveys using in-house staff without infrared windows or viewports were calculated as follows: Total man-hours per inspection of ‘inspectable’ equipment: 331 hours (23 days); staff electrician internal charge-out rate at $125 per hour; staff thermographer to assist with panel removal, etc. (a two-man task); PPE suit-ups, twice per day, per man (30 minutes per man per suit-up); one man-hour per compartment panel for safe removal, etc. (x two for two-man teams); and 147 individual panels to inspect (see Table 3). Using these figures, the cost of traditional inspections with the in-house team totalled $41,375.

After the infrared windows were installed, and there was no requirement to remove panels or wear increased levels of PPE, the task became a one-man job. The increased efficiency and economies of motion and manpower that infrared windows provided significantly decreased the time required to complete a survey to just two eight-hour days for a total of 16 man-hours.

The costs associated with an infrared survey using the IR windows were as follows:

Inspection time (16 man-hours) — $2,000; PPE suit-up time — no cost; total — $2,000 (Table 4).

Compared to the costs of traditional inspections, the paper mill now saves $39,375 per inspection cycle because of the efficiencies gained through the use of infrared windows.

Return on investment

Table 5 combines the data to illustrate the ROI for the paper mill based on the initial investment of the IR windows, the investment in installation and the costs to perform surveys using the windows, compared with the mill’s traditional costs of using its in-house team when not using any windows.

The application of infrared windows pays dividends as early as mid-way into the second inspection cycle, yielding almost $18,000 in savings, which can be put back into the budget by the end of the second cycle. In just five inspection cycles, the mill shows a savings of over $135,000.

Moreover, because inspections can be completed with greater ease and without increased risk to the plant, personnel and processes, the frequency of inspection cycles has been increased to quarterly, reflecting best-practices recommendations that were previously not feasible and thought to be unattainable.

The new inspection cycle brings ROI to the plant in just one quarter, while reducing the risk of catastrophic failure amo
ng the plant’s critical power distribution systems, which will in turn minimize production losses due to equipment failure.

Additional window installations were planned and scheduled for the facility’s next shutdown. Because the customer’s in-house electricians were trained to install the windows, the installation costs for future windows will be a fraction of the cost for the original installation, saving even more money and accelerating the ROI for the additional windows.

A portion of the financial savings were used to continue to build and strengthen the mill’s predictive maintenance program through the purchase of a second IR camera for the maintenance electricians, further underscoring the mill’s commitment to the practical use of technology to ensure uptime while enhancing the safety of its workers.

Martin Robinson is a Level III thermographer with IRISS Inc. For more information, visit www.iriss.com.

Reader Service Card No. 397

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Ins tal lat ions dur ing normal business hours al lowed much more flexibility, therefore all

‘live works’ were completed dur ing these per iods .


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