Preventive maintenance has many definitions and variations depending on the utility or manufacturer. For the purpose of this article, preventive maintenance is defined as regularly scheduled inspections, tests, servicing, repairs, replacements, and other tasks intended to reduce the frequency and impact of equipment failures. Preventive maintenance is not corrective maintenance or breakdown maintenance (which include repair or replacement activities not occurring on a regular schedule). Preventive maintenance includes scheduled preventive maintenance activities, predictive maintenance activities, and inspection activities.
The objectives of a preventive maintenance program are:
- Minimize corrective and breakdown maintenance, maintain satisfactory equipment conditions, and improve plant reliability through the use of preventive maintenance activities, predictive maintenance activities, and inspection activities.
- Identify maintenance actions on important equipment, and incorporate into the preventive maintenance program those maintenance activities that result in the greatest benefit within the available budget.
A preventive maintenance program must be well defined, periodically reviewed, and adjusted as necessary. The preventive maintenance program should include activities that the manufacturer recommends or that experience indicates are required. Maintenance procedures should be written for each piece of equipment in the program. Each procedure should describe the maintenance activities to be performed in sufficient detail to ensure proper implementation.
Predictive maintenance emphasizes the use of component performance criteria to determine the equipment condition or degradation with the overall objective of identifying incipient failures before they affect other equipment.
Equipment inspections are a systematic approach to the gathering of information relating to equipment general condition. This program involves periodic inspection of each piece of equipment by a qualified maintenance mechanic or engineer and serves as a method of evaluating gathered information, identifying recurring problems, and developing corrective actions.
To be successful, a PM routine must be complete. It must have the following:
- Description of the equipment
- Location of the equipment
- Detailed task list with step-by-step procedures for each task
- Type of craft required to complete the task and estimated labor hours for completion
- List of all materials needed for the job
- List of all tools required for completion
- List of all required permits, clearances, and tags
- List of all safety requirements, including PPE, safety materials, hazardous waste prevention/cleanup, and fall protection, etc.
- Access requirements and notifications to be made
- Manuals, prints, sketches, specifications, and other necessary references
- Paper to write up any unusual conditions or conditions that require immediate attention
Scheduling should never be viewed as a short-term evolution. It must be planned for the entire year, or longer, if necessary. In scheduling far enough in advance and having the schedule reviewed by those sections or departments affected by the outage, the likelihood of a scheduling conflict is minimized. Also, no one can ever say that they were never notified of the scheduled PM.
To improve their willingness to schedule the PM when needed, you must be willing to be ready on time, complete the job on schedule, and communicate with all involved if a situation arises that will delay or keep that piece of equipment out of service. Effective communication at all times will reduce any hard feelings that may arise.
When planning the PM schedule, you must take into account the labor required and skills available during that period. Is it a heavy vacation period? Are your most skilled workers going to be available during that period? If possible, assign specific people to each PM.
Are your efforts paying off? Are you accomplishing what you planned? What can be done to improve our effort Monitoring and auditing the PM evolutions can answer these and many other questions? This is accomplished by keeping track of:
- How many PMs were completed versus how many were planned.
- How many PM hours were done as compared to the total work hours.
- The total backlog of PM by craft, section, equipment grouping, etc.
- What equipment breakdowns have occurred in the reporting period (Where has the PM system failed and what is required to prevent it from failing the next time)
The MP2 system is a computerized maintenance management system (CMMS) used for managing maintenance routines. Some of the areas monitored by this system are:
- Investigation of equipment down time
- Identification of critical maintenance areas
- Justification for additional maintenance funding
- Provision of maintenance reports for all levels in the corporation
- The MP2 system also has the following characteristics:
- System is password protected for authorized access
- Employee information can be entered into system for all maintenance employees
- Vendors and equipment manufacturers information can be entered into the system to facilitate ordering parts or requesting information.
-Items supplied by vendor
- System links to OSHA for regulations that pertain to specific operations or equipment.
- Provides information on equipment (systems, individual pieces, subassemblies, etc.) .
-Drawings or word processing data attached to files
-User-defined fields for additional relevant information
- Creates service contracts for equipment under warranty.
- Creates nameplate information sheets.
- Creates variables to help track trends for changes in monitored values.
- Provides failure analysis records for each piece of equipment to record the reasons for failure and the solutions found, determine trends, and assist in troubleshooting.
- Creates inventory for all spare parts to track usage and costs.
- Creates requisitions, quotations, and purchase orders.
- Creates task lists for maintenance evolutions, including frequency of each task and scheduling of each task, and generates a work order.
- Creates work requests manually by the individual requesting the work.
- Schedules work specifying normal workdays, scheduled outages, exceptions, etc.
-Determines workload by day, week, or month and uses available manpower to increase or decrease workload.
- Generates work orders either automatically for scheduled work or manually by the individual authorized to make the request. When work is completed and all relevant information is entered, the system updates all associated records.
- Notifies you that you need to schedule statistical predictive maintenance when equipment varies outside its normal operating parameters.
- Generates a variety of charts, graphs, and reports for the various levels of management requiring this information.
- Contains utilities for importing and exporting data.
The usefulness of the MP2 system is only as good as the person entering all the pertinent information. Failure to include the following will render the system useless in terms of analyzing and/or predicting machinery failures:
- Work accomplished
- Parts used
- Defects found and repaired
- Causes of equipment failure
- Total hours expended
The following are generic PM practices. No periodicity is assigned as it depends on the equipment, the manufacturers recommendation, facility experience, and the environment the facility and equipment are subjected to.
- Check the condition of floors, ceilings, and walls for evidence of deterioration.
- Check for visible signs of leaks.
- Check for hazards (electrical, mechanical, structural, physical, tripping, etc.).
- Check the condition and operation of faucets, toilets, and showers.
- Check smoke detectors and CO detectors.
- Check the fire alarm system.
- Check the firefighting equipment.
- Check all doors for proper operation; ensure that exits are not obstructed.
- Check for accumulation of trash in storage areas.
- Check for evidence of insect infestation.
- Check the condition of the paint and walls.
- Check for broken windows and doors.
- Check the condition of all railings.
- Check for plants growing on the building or its foundation.
- Clean the roof. Use care when working in high places; employ adequate fall protection.
- Clean roof drains and gutters. Test drains and downspouts by flushing them with water.
- Inspect the condition of the roof.
- Inspect gutters for adequate anchoring and tighten, if necessary.
- Inspect the stack and all roof penetrations.
- Remove any plant life growing on the roof.
- Clean up any debris found.
- Check the grounds for broken glass and debris.
- Check the condition of the sidewalk.
- Check the condition of the driveway and parking area.
- Check the storm water drains.
- Check the condition of the plants and lawns.
- Check the condition of the trees; verify that no branches are about to fall.
- Check for cleanliness around the dumpsters.
- Check the condition of any fencing.
- Check the mailbox area.
- Replace any burned out lamps and clean reflectors, refractors, and globes.
- Check the gaskets for proper seating.
- Check the condition of lamp standards and mountings.
- Check the operation of automatic and manual switches.
- Check electrical connections and boxes for signs of deterioration or overheating.
- Check outlets for proper operation.
- Test GFCI outlets for proper operation.
- Clean the air intake.
- Change the air filter.
- Check the blower motor in operation for excessive noise or vibration.
- Clean the motor and ductwork.
- Check the condensate drain pan for proper drainage.
- Check the flexible duct connectors.
- Secure any loose guards and panels.
- Check the condition of all electrical hardware and connections.
- Check the safety controls and equipment.
- Check for proper operation of the interior unit.
- During the cooling season, check the condenser motor bearings for excessive noise or vibration.
- During the cooling season, check the condenser air intake, discharge, and coil as required.
- During the cooling season, check the condition of all refrigerant piping and insulation.
- During the cooling season, secure any loose guards or access panels.
- During the cooling season, check the operation of the exterior unit.
- Check vehicles for cleanliness, including clean windows, mirrors, and head and tail lamp covers.
- Check the operation of turn signals, stop signals, backup lights, head and tail lights, and emergency blinkers.
- Check the operation and condition of sideview and rearview mirrors.
- In the motor compartment, check:
a. Condition of belts and hoses
b. Check all fluid levels:
- Check tire condition for uneven wear, thread depth, and cupping.
- Turn the engine on and check the gas level, dashboard alarms, interior lights.
2. Depending on mileage
- Change the oil
- Change the oil filter
- Rotate the tires
- Check/change the antifreeze
- Change the transmission fluid
- Change the air filters
- Change the PVC valve
- Change the gas filter
3. As required
- Change the tires
- Change the mufflers
- Change the shock absorbers
- Change the brakes