Scheduling preventative maintenance – timing is everything
OK, before I begin, I need to state aloud: I am a big fan of preventive maintenance and am not advocating that maintenance operations teams cut back on PMs. However, applying “CMMS Intelligence” to certain scenarios allows maintenance teams to reduce PMs, yet still achieve maximum uptime.
Traditionally, most organizations issue PMs on a calendar basis. As an example, a manufacturer needs to periodically check on one of the plant’s air handling units. In a perfect world, a CMMS system triggers a reminder that a PM is due and the work order is completed in a reasonable timeframe. Even when running a paper-based system most organizations schedule calendar-based PMs.
But what if “every four weeks” is too frequent? In some cases the PM will be completely skipped if there are not enough resources to get it done. In other cases you struggle to get PMs done every time, only to find out that you might be doing them too often. There are other variables to drive more efficient, less frequent PM schedules.
The case for meter reading-based PMs
In many cases there is data to support more intelligent PM scheduling. For example, the AHU manufacturer’s suggested routine maintenance protocol is once every 500 operating hours, rather than every four weeks. Unless that AHU is running 24/7, 500 hours of usage will stretch well beyond four weeks.
Most CMMS systems allow users to enter “meter readings” (MRs), numerical readings that can be associated with any asset. A CMMS system can set different variables for MRs, i.e., “hours run,” “pressure,” “temperature,” “widgets produced,” etc., and show maintenance staff when an MR for a piece of equipment is outside of acceptable tolerance. MRs can also be used for trending purposes to help determine when PMs should be performed.
For example, if you want to track “hours run” for an AHU, take periodic meter readings and once you hit a threshold of 500 hours, initiate a PM.
To prove “every four weeks” is too frequent, start taking metering readings and track them in your CMMS system. It may turn out that the AHU unit is running 15 hours per day, averaging 105 hours of runtime per week versus the total 168 hours that make up a week. Initiating a calendar-based PM schedule every four weeks, based on the 105 hours of weekly run time, would trigger the PM every 420 hours—80 hours shy of the manufacturer’s recommended schedule or nearly an extra week of unnecessary maintenance checking. Over time, these extra PMs would add up to wasted parts and labor costs.
Or a manufacturing operation may need to schedule PMs based on accumulating production volume, i.e., output in widgets produced, with maintenance warnings issued at set intervals. A calendar-based schedule will not change as production volume changes over time, again risking too frequent or infrequent PMs.
Do your research
To develop a more accurate PM schedule based on meter readings, know your equipment and gather accurate data to support the manufacturer’s recommended maintenance schedule. Rely on your equipment vendor or previous experience to determine the most accurate intervals to perform PMs. Make sure your CMMS system supports both calendar and meter-reading based PMs.
Can you schedule too many PMs? Yes you can. Still, too many PMs are probably better than not enough. CMMS and meter readings can help any organization implement a more intelligent, accurate, and efficient PM schedule. Lachance is president and chief technology officer for Smartware Group, which produces Bigfoot CMMS.