How to Balance Your Preventive Maintenance Workload
Are you tired of that month, quarter or year-end crunch to get your preventive maintenance (PM) work done? Minimize the chance of this happening again with the steps below.
Before you begin, some fundamentals:
- Be comfortable with linking cells in formulas within a spreadsheet program such as Excel.
- Have the right people with the right skills available to do the work.
- Develop a balanced PM work schedule based on the shop’s capacity to make sure the work can be completed in a timely manner.
Step 1: Include these elements:
- The priority of the equipment – Use established criteria such as criticality to prioritize the equipment or systems that feed into your PM plan. There is a process for determining criticality but that’s a separate article.
- The labor hours by shop or skill for performing each PM event – Example: A monthly air handler PM at a pharmaceutical requires 3 hours for HVAC mechanics. These labor hours constitute the workload. The workload refers to labor hours, not task duration. If 2 HVAC mechanics work on the PM for 1.5 hours, the total labor still equals 3 hours.
- Equipment availability based on the production schedule. Some PM tasks may have to go to the off shifts in order to get access or wait for breaks in the production schedule. Conflicts over availability should be resolved through an existing protocol (which means you should work this out in advance).
- Materials such as filters, gaskets, etc., required for completing the PM tasks. These need to be available when the PM is scheduled for execution so a link between PM scheduling and procurement and inventory should be established to assure PM completion.
- Other factors as appropriate.
Step 2: Identify the following:
- The labor hours required by skill or shop for every PM work order planned for the year based on the OEM recommendations, or prior experience (what happened last time you did this PM), or the current plan.
- The OEM or regulatory prescribed frequency interval (monthly, annually, etc.), and
- The capacity in man-hours of each shop or department required to do the work. These are the hours that can be devoted to real work, aka wrench time, net of meetings and training, etc. A balanced PM schedule supports a dedicated PM crew’s timely completion of the PMs. That’s why Maintenance staffing should always begin with allocating resources to completing the PMs.
Step 3: Create a schedule spreadsheet.
Create a spreadsheet for the shop that will show 52 weeks across the top and each piece of equipment down the left side. Load the labor hours required for each PM each week per the original frequency interval or the way it is now.
- Create a fixed table or location for the hours per piece of equipment and enter a cell reference formula in the row for the week to pull them in. This formula can be easily moved from week to week later for balancing.
- Next, the PM scheduler will need to calculate and enter the available capacity of the shop and include it for each week of the spreadsheet in a row across the bottom. Create a simple formula to compare it to the sum total workload demand for all equipment served by this skill for each week.
- Set up your spreadsheet to color-highlight cells that flag the PM workload exceeding (or falling below) the shop’s capacity. This will help you recognize which PM activities to reschedule to balance the workload.
Step 4: The balancing act.
Now that your spreadsheet contains all the PM and shop capacity information, the scheduler can move PM tasks from week to week to reduce the variance between workload and shop capacity, producing as balanced a workload as possible. PM tasks can usually be rescheduled for a shorter time interval, or “pulled in”, for the purposes of balancing. Be sure to work with production control in advance to adjust the production schedule accordingly.
Engineering or the OEM should be consulted if tasks are to be “pushed out” to make sure there are no negative consequences for equipment. From a Lean perspective, tasks that can be performed at an interval best suited to the equipment’s performance will help reduce operating costs. In regulated environments such as hospitals or pharmaceuticals, care must be taken to ensure that frequency changes are in compliance with health care equipment regulations.
Continue assessing each week’s workload and shop capacity until all PM tasks for the shop have been scheduled to produce the best balance possible.
After balancing the annual PM work, it is wise to try to ‘shadow’ the PMs. One example of shadowing would be to include the monthly PM tasks in the quarterly PM job plan so the CMMS does not generate two separate work orders when the quarterly PM is released. In this case, the monthly PM tasks are in the quarterly PM’s ‘shadow’.
Step 5: Load the new PM schedule.
To complete the balancing process, the new frequencies must be transferred to the work orders in the CMMS.
About the Author
Steve Mueller is Director of Commercial Operations for Daniel Penn Associates. He is responsible for project development, management and delivery of results for the company’s private sector clients. Steve has over 30 years of consulting experience.
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