About 80 percent of the wastewater comes from homes, with the remaining 20 percent generated by business. The service area includes 21 cities and three special districts covering 471 square miles. The Reclamation Plant 1 is located in Fountain Valley and the Treatment Plant 2 is located 6 miles from Plant 1 in Huntington Beach (Fig 1).
Prior to the implementation of the Vibration Analysis program at OCSD, equipment was repaired as it failed, and put back into service with little documentation and no follow-up. Because of the increased use of Root Cause Analysis many changes have been implemented to avoid recurring failures and to identify opportunities to make lasting improvements. Now work is planned and scheduled according to severity and priority.
The Vibration Analysis program at OCSD has been in place since 2002. It began with baseline vibration monitoring being conducted on critical equipment with consultant assistance. Three years ago the Predictive Maintenance (PdM) team with the support from upper management established a three step strategy plan to achieve PdM best practices at OCSD.
• Trained Reliability Maintenance personnel in both preventative predictive maintenance best practices
• Self assessed Vibration Analysis in 2007
• Continuous improvement based on assessment results
In 2008 Uptime Magazine awarded OCSD PdM program as "The Best Vibration Analysis Program of the Year". This paper describes the key elements of OCSD's program.
"Effective implementation of Predictive Maintenance technologies to provide reliable process equipment by having the ability to plan maintenance and repair activities, and by reducing treatment process interruptions and overall maintenance costs."
Training Program for Reliability Maintenance Team
The Reliability Team consists of a Reliability Engineer and two Reliability Technicians. All of them hold certifications in Vibration Analysis. Reliability Engineer is certified as Vibration Analyst Category III by the Vibration Institute and the Reliability Technicians are certified as Level I Vibration Analyst by CSI Emerson.
The Reliability Maintenance Team has created a training matrix including formal courses hours, hands on experience in months and qualifications required to achieve each certification level. Training is self directed and allocated a dedicated budget for two fiscal years in advance. OCSD invested in a Turnkey Vibration Training System to train qualified technicians in vibration analysis. This training system is used as part of the hands-on training in laser alignment for direct and belt driven machines without impacting the plant process equipment.
Equipment Criticality and Quartile Coverage
The criticality of an asset is used to determine the strategy for the PdM management of an asset, since more critical assets should be managed/maintained to a greater degree than less critical assets. Asset criticality is calculated using a "Criticality Analysis Tool" (Allied Reliability) from the multiplication of the probability of a failure occurring and the resulting consequences of that failure.
Three criticality categories have been applied to assets; high, medium and low criticality. High criticality assets are monitored on a monthly basis, medium and low criticality assets are monitored on a quarterly basis.
The equipment coverage best practice is based on the percentage of maintenance costs against Replacement Asset Value (RAV). The best practice or first Coverage means the lowest equipment maintenance costs. The first coverage for wastewater industry based on rotating machinery assets for Vibration Analysis is 62 percent. Currently six hundred (600) pieces of equipment are monitored as part of the PdM program.
Constantly more assets are included as part of the vibration program based on criticality. "Equipment Coverage Benchmark" (Allied Reliability) for wastewater facilities is used to determine what quartile we are on. Our goal is achieve first Quartile Coverage by the end of FY09-10. OCSD first Quartile Coverage would be around 744 equipments.
Procedures, standards and workflows have been established and are followed by the
personnel involved with PdM activities.
• Vibration Workflow Diagram, OCSD 2005.
• Vibration Trending, Analysis and Report Writing Procedure, OCSD 2008.
• Mechanical Vibration - Evaluation of machine Vibration by Measurements on Non-Rotating Parts - ISO 10816-3, 1998
• Condition Monitoring and Diagnostics of Machines - Requirements for Training and Certification of Personnel - Part 2: Vibration Condition Monitoring and Diagnostics - ISO 18436-2, 2003
Acceptance Testing of New and Rebuilt Assets
Before the PdM program was implemented, equipment was repaired and put back in service without any follow up; therefore a lot of rework was done. At the present time when equipment is repaired, overhauled or replaced; acceptance testing is done to accept or reject the work done. Figure 2 below shows the PdM Process follow in OCSD.
Solid Communication Strategy
A monthly vibration report has been developed for OCSD's two facilities and 15 pump stations. These reports have been a great communication tool for Operations and Maintenance. The vibration reports provide a quick overview of high, medium and low criticality assets providing equipment status, condition and a going forward plan of action for repair or monitoring.
The results of the vibration surveys are included on this "Machinery Vibration Condition Report"; which contains severity and priority codes (Fig 3). Severity codes provide the asset condition. This is reflected in CMMS as condition rating. Priority codes provide a time frame to plan and schedule repairs. This is reflected in CMMS as priority (emergency, urgent and routine).
In addition, a report has been created for sharing machinery case histories with O&M personnel. These reports along with other maintenance reports are posted in the maintenance shops. The benefits of the PdM program are formally communicated to management and employees by metric reports, return on investment reports and formal presentations with case histories and savings due to implementation of the PdM program at OCSD.
Root Cause Analysis
The Root Cause Analysis (RCA) program provides documentation on why a piece of equipment failed. The use of RCA software (Fig 4) by trained personnel has resulted in implementing changes to avoid recurrent adverse events of similar consequences and identifies opportunities for making lasting improvements.
Preventive Maintenance Optimization
As part of continuing improvements a Preventive Maintenance Optimization program is being implementing using a "PM Evaluation Tool" (Allied Reliability). All the Preventive Maintenance tasks are evaluated and actions are recommended. Based on the results PM tasks are reclassified in 6 categories:
• Non-value added/re-assign: delete
• Non-value added/re-assign: lubrication route
• Non-value added/re-assign: operation care
• Replace with PdM/NDT
• No modifications required
Figure 5 shows a PM Optimization study conducted on all Preventive Maintenance tasks for rotating machinery at OCSD's Huntington Beach and Fountain Valley facility resulting in recommended changes. Based on this study 3,455 man-hours can be reassigned to other needed areas every fiscal year. Representing savings for $172,750 (man-hour @ $50) annually.
PdM Reliability Metrics and Benchmark
The measurement of the PdM Reliability Metrics is an essential part of our commitment to the program continuous improvement. These metrics are used to measure performance and effectiveness, identifying gaps and improvement areas in our vibration program.
The top three metrics used to measure the effectiveness of our PdM program are:
• Asset Health: Benchmark 80%
• PdM Effectiveness: Benchmark 80%
• PdM Data Collection Schedule Compliance: Benchmark 90%
PdM Cost-Benefit and Return on Investment
The maintenance cost avoidance due to the PdM program is calculated based on historical data. This data is gathered from similar pieces of equipment that previously failed and an average maintenance cost is assigned to compare against maintenance cost when the problem is detected by vibration analysis. Figure 7 shows the total savings and return on investment (ROI) for FY07-08 due to the implementation of PdM Best Practices at OCSD.
OCSD PdM Program Today
At the present time OCSD Vibration Analyst program is operating at World Class level (Fig 8). Then the Reliability Maintenance Team is focusing in this program continuous improvement and applies a similar strategy for achieving Oil Analysis and IR Thermography best practices at OCSD. Some of the Reliability Maintenance Team initiatives as follow:
• Oil Sampling and Analysis of all types of oil shipped to OCSD
• Oil Analysis routes for critical equipments at Plant 1 and Plant 2
• Ultrasound Lubrication systems for grease lubricated bearings
• Use of clear grease container
• Acquisition of several thermal imagers for reliability and maintenance personnel
• Assisted other Wastewater Treatment Plants in California on PdM program implementation.
Article Submitted By Santiago Escobar