Measuring maintenance productivity using a closed-loop system

Key conceptsProactive maintenance management includes task lists with allotted completion times, work order system to schedule repairs, and breakdown investigation.Skilled trades, planner/scheduler, maintenance engineer, maintenance supervisor, and storeroom personnel all contribute to the success of the PM program.

Key concepts

  • Proactive maintenance management includes task lists with allotted completion times, work order system to schedule repairs, and breakdown investigation


    • Maintenance departments are continually "under-the-gun" to reduce costs, decrease equipment downtime, and improve efficiency. They are also expected to support popular manufacturing systems such as JIT, MRP, TQM, and lean manufacturing. The achievement of these goals is complicated by the fact that a majority of maintenance organizations operate in a reactive mode with efficiencies in the 30% range.

      There are several possible reasons for this low efficiency figure.

      • Maintenance trades repeatedly travel back-and-forth from the job-at-hand to the storeroom for parts, manuals, tools, and assistance.

      • Equipment is unavailable for maintenance personnel to work on because it is operating or in a setup mode.

      • Travel time to the equipment is lengthy and trades people become distracted en route to the job.

      • Different skilled trades are required to complete a repair, which keeps the original person waiting for their arrival.

      • Problem reported to maintenance was incorrect, resulting in the wrong trade being dispatched to the job.

        • All these factors are the pitfalls associated with a maintenance department operating in a reactive mode.

          <table ID = 'id3456446-29-table' CELLSPACING = '1' CELLPADDING = '1' WIDTH = '95%' BORDER = '.5'><tbody ID = 'id3456456-29-tbody'><tr ID = 'id3456458-29-tr'><td ID = 'id3456461-29-td'>

          </td></tr><tr ID = 'id3456475-33-tr'><td ID = 'id3456477-33-td'> The closed-loop PM system validates the equipment database on a consistent basis by continually updating information. </td></tr></tbody></table>

          Standardize the work

          The basic tool necessary to increase the productivity of the skilled trades is a form of standard work, which is a byproduct of the proactive approach to equipment maintenance. A proactive program can more than double the average maintenance department's 30% efficiency rate and reduce maintenance downtime to the 1%%MDASSML%%2% range, while fully supporting TQM, JIT, and lean manufacturing.

          This efficiency increase frees up almost half the workforce assigned to breakdowns (reactive maintenance). The additional time, money, and manpower can reduce the reliance on outside contractors, start a predictive maintenance program, redesign/modify existing equipment to increase its effectiveness, or become involved in TPM activities.

          System description

          Proactive standard work consists of preventive maintenance (PM) task lists with allotted time frames for the completion of each task. A PM work order system is used to perform deficiencies found during the PM task list work. These work orders are estimated and material is ordered before the work is assigned. The use of these basic tools allows this system to be generic and flexible enough for implementation in a wide range of organizations.

          Activities required to implement this proactive management system include:

          • Task lists with allotted completion times

          • Work order system to complete the repairs found during PM

          • Use of estimated times for work orders

          • Breakdown investigation system

          • Equipment downtime tracking system.

            • Results are evaluated by measuring the productivity of the skilled trades, using a matrix to determine actual manpower requirements, and constructing a database for the predictive maintenance program.

              The foundation for this system is the preventive maintenance program, which is accomplished by completing PM task lists for each piece of equipment included in the program. The PM task list form includes the maintenance trade needed, frequency of maintenance, equipment number, task description, time requirements, and notations for additional repair work required. A task list for each trade involved and each time period is also required.

              For example, there may be a monthly task list for a piece of machinery and a weekly, monthly, quarterly, semiannual, and annual list for a mechanic. Needs vary according to the equipment involved. Required maintenance needs are determined using manufacturers' recommendations, past histories, and inhouse experience.

              Times are tabulated at the bottom of each task list. As the daily lists come due, tabulated times are added together (see table on next page). This exercise shows exactly how many people and which trades are needed that day. Similar planning can be done weekly or monthly.

              Taking the totals for every daily task list and compiling a matrix further expands the concept. This compilation reveals how many people are needed to perform the PM program on a yearly basis, which is especially informative for budgeting purposes.

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              </td></tr><tr ID = 'id3457427-76-tr'><td ID = 'id3457429-76-td'> Paperwork flow of the closed-loop system revolves around the planner/scheduler and is another critical step toward continuous improvement. </td></tr></tbody></table>

              System management

              Track, monitor, and follow up on the PM task lists by investigating discrepancies in them. Authenticating the database solidifies the manpower requirement calculations. Analyzing and problem solving (getting to the root cause) of every breakdown ensures continuous system improvement.

              The management system consists of five major functions:

              • PM task list distribution to the skilled trades

              • PM work order time estimating, parts procurement, and distribution to the skilled trades

              • Updating task list times based on actual numbers reported

              • Updating task lists based on breakdown investigation findings

              • Auditing task lists based on breakdown investigation findings.

                • Tracking the system

                  The planner/scheduler assembles the task lists daily for those activities planned for the following day. These lists are entered into the table matrix and the result identifies the amount and type of skilled trades required for that day. The planner/scheduler then distributes the information to the maintenance supervisor for assignment.

                  Skilled trades perform the tasks assigned and indicate the time required for completion of the list. They also indicate whether any additional repairs are required, and what specifically needs to be done (replace worn V- belts, weld guard, etc). The lists are then returned to the planner/scheduler who writes up any PM work orders for those tasks that require further repairs or adjustment to the equipment.

                  The lists are turned over to the maintenance supervisor who examines each work order and determines if it is correct and justified. The supervisor then estimates the time required to perform the repair, verifies what needs to be ordered, and gives the information to the store room for procurement.

                  Storeroom personnel order the parts, but keep the PM work order until all items are received. When the package is complete, the work order is given back to the planner/scheduler, who adds this data to the tabular matrix. This list identifies additional work and the amount and types of trades needed for the following shift or day.

                  When the completed work order is returned, the planner/scheduler verifies the actual time vs estimated time. If the difference is greater than 10%, he returns the work order to the supervisor to investigate the reason.

                  The reason for the difference is noted on the work order by the supervisor and returned to the planner/scheduler. He transmits it to the PM engineer who updates the equipment history file and the PM task list (if necessary).

                  The engineer reviews the returned information and updates the PM task list (as required). If the time is lower than that in the database, the new time is entered. If it is higher, he questions the maintenance supervisor to determine what changed or transpired. This step is part of the effort to assure that the database is always in a state of continuous improvement.

                  Updating task lists

                  Every equipment breakdown must be investigated each day and a root cause established. An investigative team consisting of the PM engineer, maintenance supervisor, electrician, and mechanic meet to determine the root causes. The group should meet each day at a specific time to review every completed work order that involved a piece of equipment that experienced unscheduled downtime.

                  The PM engineer uses the results of this investigation to modify the task list. Storeroom inventory is also adjusted (if necessary).

                  The team also determines if a task list or work order was properly performed. This determination is accomplished by comparing the list with the defined root cause.

                  If there is a match, an analysis is undertaken to clarify the discrepancy. The investigation includes interviewing the people who performed past PMs to see if they were done correctly (or not at all). Inadequate training or instructions may also cause this situation. If the root cause is not part of the current task list, it needs to be added.

                  — Edited by Ron Holzhauer, Managing Editor, 630-320-7139,

                  More info

                  The author is willing to answer technical questions concerning this article. Mr. Evans is available by telephone at 315-768-8754 or by e-mail at

                  For additional related material, check out the "Maintenance" channel on our web site:

                  Daily manning requirements by trade

                  <table ID = 'id3457599-138-table' CELLSPACING = '0' CELLPADDING = '2' BORDER = '1'><tbody ID = 'id3457607-138-tbody'><tr ID = 'id3457610-138-tr' STYLE = 'background-color: #EEEEEE'><td ID = 'id3457614-138-td' CLASS = 'COPY'></td><td ID = 'id3457618-139-td' CLASS = 'COPY'> PM task lists, hr </td><td ID = 'id3457625-141-td' CLASS = 'COPY'> People required </td><td ID = 'id3457632-143-td' CLASS = 'COPY'> PM work orders, hr </td><td ID = 'id3457638-145-td' CLASS = 'COPY'> People required </td><td ID = 'id3457645-147-td' CLASS = 'COPY'> Total people </td></tr></tbody><tbody ID = 'id3457654-151-tbody'><tr ID = 'id3456540-151-tr'><td ID = 'id3456542-151-td' CLASS = 'COPY'>Machine repair</td><td ID = 'id3456548-152-td' CLASS = 'COPY'>21.2</td><td ID = 'id3456554-153-td' CLASS = 'COPY'>3.03</td><td ID = 'id3456559-154-td' CLASS = 'COPY'>9.5</td><td ID = 'id3456565-155-td' CLASS = 'COPY'>1.36</td><td ID = 'id3456570-156-td' CLASS = 'COPY'>4.39</td></tr><tr ID = 'id3456577-158-tr'><td ID = 'id3456579-158-td' CLASS = 'COPY'>Electrician</td><td ID = 'id3456585-159-td' CLASS = 'COPY'>14.1</td><td ID = 'id3456591-160-td' CLASS = 'COPY'>2.01</td><td ID = 'id3456597-161-td' CLASS = 'COPY'>3.3</td><td ID = 'id3456602-162-td' CLASS = 'COPY'>0.47</td><td ID = 'id3456608-163-td' CLASS = 'COPY'>2.48</td></tr><tr ID = 'id3456615-165-tr'><td ID = 'id3456617-165-td' CLASS = 'COPY'>Lubrication servicer</td><td ID = 'id3456622-166-td' CLASS = 'COPY'>26.9</td><td ID = 'id3456628-167-td' CLASS = 'COPY'>3.84</td><td ID = 'id3456634-168-td' CLASS = 'COPY'>2.1</td><td ID = 'id3456640-169-td' CLASS = 'COPY'>0.3</td><td ID = 'id3456645-170-td' CLASS = 'COPY'>4.14</td></tr><tr ID = 'id3456652-172-tr'><td ID = 'id3456654-172-td' CLASS = 'COPY'>CNC repairman</td><td ID = 'id3456660-173-td' CLASS = 'COPY'>18.7</td><td ID = 'id3456666-174-td' CLASS = 'COPY'>2.67</td><td ID = 'id3456671-175-td' CLASS = 'COPY'>16.4</td><td ID = 'id3456677-176-td' CLASS = 'COPY'>2.34</td><td ID = 'id3456683-177-td' CLASS = 'COPY'>5.01</td></tr><tr ID = 'id3456690-179-tr'><td ID = 'id3456692-179-td' CLASS = 'COPY'>Total man hours</td><td ID = 'id3456697-180-td' CLASS = 'COPY'>80.9</td><td ID = 'id3456703-181-td' CLASS = 'COPY'></td><td ID = 'id3456708-182-td' CLASS = 'COPY'>31.3</td><td ID = 'id3456713-183-td' CLASS = 'COPY'></td><td ID = 'id3456718-184-td' CLASS = 'COPY'></td></tr><tr ID = 'id3456723-186-tr'><td ID = 'id3456725-186-td' CLASS = 'COPY'>Total manning</td><td ID = 'id3456731-187-td' CLASS = 'COPY'></td><td ID = 'id3456735-188-td' CLASS = 'COPY'>11.55</td><td ID = 'id3456741-189-td' CLASS = 'COPY'></td><td ID = 'id3456746-190-td' CLASS = 'COPY'>4.47</td><td ID = 'id3456751-191-td' CLASS = 'COPY'></td></tr><tr ID = 'id3456757-193-tr'><td ID = 'id3456759-193-td' CLASS = 'COPY'>Grand total manning</td><td ID = 'id3456765-194-td' CLASS = 'COPY'></td><td ID = 'id3456769-195-td' CLASS = 'COPY'></td><td ID = 'id3456773-196-td' CLASS = 'COPY'></td><td ID = 'id3456778-197-td' CLASS = 'COPY'></td><td ID = 'id3456782-198-td' CLASS = 'COPY'>16.02</td></tr></tbody><tr ID = 'id3456790-201-tr'><td ID = 'id3456792-201-td' CLASS = 'COPY'></td><td ID = 'id3456797-202-td' CLASS = 'COPY'></td></tr><tr ID = 'id3456802-204-tr'><td ID = 'id3456804-204-td' CLASS = 'COPY'></td><td ID = 'id3456809-205-td' CLASS = 'COPY'></td></tr><tr ID = 'id3456814-207-tr'><td ID = 'id3456816-207-td'></td></tr></table>

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