It’s well-known that performing maintenance on a condition-based or reliability-centered basis is the preferred method for plant maintenance operation. This is the safest and most cost-effective method, and it’s the objective for most organizations. But how does one begin the journey?
why a reliability office?
The infrared thermography program previously consisted of a yearly survey of all the motor control centers that was driven by corporate insurance requirements and focused on power distribution. This work was always outsourced, and every year several critical and severe issues were found.
After the team completed Level I Thermography training, routes were created to perform surveys of all the motor control centers, critical drives, and PLC panels on a semi-annual basis. These routes and surveys were more thorough than the yearly insurance survey and were focused on reliability. The routes were configured based on cabinet locations, opposed to which equipment was being powered. This increased the efficiency of the inspections and reduced waste. The routes were leveled so that the technicians performed thermography routes each month.
When the infrared routes began, a high number of reliability issues were found in many panels. Some of the issues were loose wires, unlubricated switches, broken fuse holders, and unbalanced loads. In the beginning of the program, many of the faults were deemed critical or severe. After the first 18 months, the number of reliability issues within the panels were significantly decreased, and now the rate at which issues are found in panels are one to three a quarter.
Working with open power cabinets exposes the technicians to arc flash hazards. To eliminate the safety risk, infrared windows were installed on cabinet doors to allow the inspections to occur without opening the cabinet doors.
Thermography surveys were not limited to electrical inspections. Rounds were set up to inspect the mill steam traps on a bimonthly basis. The first year of inspections yielded the repair or replacement of almost all of the steam traps in the mill. Many bypass circuits and valves were found to be faulty or in the incorrect position. Ultrasound was introduced about six months into the steam trap survey program. The ultrasound would confirm steam trap faults and would at times reveal faults that went undetected with thermography.
Thermography was further expanded to mechanical inspections of the asset. Routes were established to survey areas of the asset. These routes identified numerous faults, including bad bearings, failed check valves, and air leaks. This technology was also employed in tissue machine hood surveys. Leaks could be detected from a safe distance, limiting the technician’s exposure to the heat from the hoods.
As the reliability office became proficient with the initial three technologies of lubrication, vibration, and thermography, team members focused on the development of their skills with precision alignment. Formal training was conducted for not just the reliability office members, but for other mechanics and all of the mechanical engineers in the mill.
Precision alignment consisted of shaft alignment and soft foot. Before the reliability office, precision alignment focused on shaft alignment only and ignored soft foot. Best practices were developed and documented for precision alignment, base plate design, and foundation and grouting.
Precision alignment was easily tied to engineering practices. Many aspects of equipment design and installation practices to improve shaft alignment and to minimize the effect of soft foot can be addressed at the design level. This promoted design for reliability, instead of attempting to improve the reliability of the equipment after installation and startup.
Root cause failure analysis
Before the reliability office was instituted, the mill repaired the equipment to operating condition, but most of the equipment would fail again soon after. Failed components would be thrown away without investigating what may have caused the failure. When failed components were inspected, no documentation or sharing of the learnings occurred. The mill’s reaction to failures was to create a preventive maintenance inspection or replacement based on a time interval. This resulted in repetitive failures of the same or similar equipment, and a proliferation of preventive maintenance work that could not be completed within the work capacity of the mill or the planned downtime of the asset.
The reliability office began to investigate failures on major equipment. Root causes were identified and documented in root-cause failure analysis reports. The reports were shared with everyone in maintenance, engineering, and operations. Because the mill is one of six in the sector with similar assets producing similar products, the reports were also shared with the maintenance and reliability leaders at the other mills. The reliability office developed and authored the sector root cause failure analysis framework, which included the report structure and communication upon completion.