Machinery Lubrication magazine published by Noria Corporation
Issue link: https://www.e-digitaleditions.com/i/290460
32 March - April 2014 | www.machinerylubrication.com mAINteNANCe ANd relIABIlIt Y enced or even certified replacements and get them up to speed. In the meantime, monitoring languishes, reliability decreases and the PdM program may even be abandoned if its true worth hasn't been documented. This can result in a decline in avail- ability while the maintenance strategy reverts to more costly approaches such as reactive maintenance. To mitigate this risk, it is a good idea to continue a relationship with the PdM contractor to support the program when required. Another pitfall to avoid is deciding that a PdM program can be done cheaply. With this strategy, simpler, easy-to-learn PdM tools are acquired, but more sophisticated suites are never applied, even with contractor support. In these cases, the diag- nostic and long-term analysis capabilities of advanced PdM software and the full potential of a comprehensive PdM program are never realized. The opposite situation can also create problems. Sophisti- cated and costly PdM tools are purchased and put into the hands of maintenance crew personnel who are given training they either don't apply soon after the classes or have too few opportunities to learn how to apply them on the job. Benefits of a Two-tiered PdM Program A two-tiered PdM program that applies multiple technologies can be beneficial for many organizations, especially those with plants dispersed over a wide geographic area and/or where semi-autonomous maintenance crews are employed. These benefits are over and above those of a traditional team-only or decentralized, non-integrated approach. Under this two-tiered arrangement, a skilled PdM team with sophisticated data-collection hardware and analysis software supports and collaborates with maintenance crews equipped with simpler but sufficiently sensitive tools for detecting and confirming problems in their plants. With this type of program, local maintenance crew personnel are empowered to declare an asset ready for return to operational service. The PdM capability provides maintenance personnel with their own quality-assurance tools. This is done by having the local maintenance crews responsible for post-maintenance testing, which is performed to determine if a restorative or miti- gating task has been successful in fixing a reported problem, as well as to ensure that new problems weren't introduced in the course of maintenance. In the event post-maintenance testing reveals an abnormal condition, help from the PdM team can be requested to define what may have gone wrong during mainte- nance so it can be remedied. There is also a division of labor and responsibilities in the employment of predictive technologies between the PdM special- ists on the PdM team and the PdM practitioners on the maintenance crews. This can pay dividends in three ways: 1. The maintenance crews, which are equipped with simple but effective tools, can perform post-maintenance testing and make the "go/no-go" calls with a reasonable level of assurance. This boosts their confidence and self-esteem. 2. It enables staff through involvement in PdM technology to determine if they are interested in becoming future PdM team member candidates. 3. The PdM team is relieved of having to perform post-mainte- nance testing under time constraints and pressures to return the asset to service as soon as possible. Another advantage of a two-tiered PdM program is that it offers added opportunities for cooperation between the PdM team and local maintenance crew members. For example, when baseline testing by PdM team members is being conducted, main- tenance crew PdM practitioners should be present with their PdM tools to take readings at the same time. This allows the mainte- nance crew members to compare readings from their simpler tools to those taken by the PdM team members on their more sophisti- cated equipment. This will educate both groups on each other's capabilities and limitations, and enhance future cooperation. Case Study: The Metropolitan Sewer District of Greater Cincinnati The Metropolitan Sewer District of Greater Cincinnati (MSDGC) serves 800,000 customers and has approximately 600 In a two-tiered predictive maintenance program, a skilled PdM team with sophisticated data-collection hardware and analysis software supports and collabo- rates with maintenance crews equipped with simpler tools for detecting problems in their plants. The Metropolitan Sewer District wastewater Treatment Division operates seven major treatment plants and more than 100 smaller treatment facilities that process an average of 180 million gallons of raw sewage each day.