Scheduled maintenance critical percentage

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Scheduled maintenance critical percentage (SMCP)


Planned or scheduled maintenance is a list of predetermined maintenance actions carried out at regular time intervals that are aimed at the prevention of breakdowns. It has been proven again and again that sporadic ongoing repair leads to asset deterioration, a shorter asset lifetime and increased long-term capital cost. The primary goal of scheduled maintenance is to prevent equipment failure before it actually occurs. This includes inspections, adjustments, regular service and planned shutdowns. Standard scheduled maintenance checks like this can help increase the lifetime of your assets and reduce the need for part repair or replacement.

So, when you’re faced with numerous overdue scheduled maintenance actions, or “PMs”, how do you determine which PM needs to be done first? You have 2 PMs on identical systems – the first is a monthly that is 3 days late, the second is a quarterly PM that is 5 days late. It would seem that the 5 day late PM should be completed first. By calculating the scheduled maintenance critical percent for the preventive maintenance action, we can determine which PM should be completed first.

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How is SMCP calculated?

Scheduled maintenance critical percent shows how late your scheduled maintenance work orders are in relation to the maintenance schedule. The higher the percentage, the more attention you should pay to that scheduled maintenance work order. It takes into consideration the number of days late versus the PM cycle. scheduled maintenance critical percent is calculated from the following formula:

Formula: (Days late + PM cycle) /PM cycle * 100%

Lets take a closer look at the example above:

Monthly PM that is 3 days late:  Critical % = (3+30)/30 * 100% = 110%

Quarterly that is 5 days late:  Critical % = (5+90)/90 * 100% = 105%

On first impressions, it may seem the 5 day late quarterly PM should take precedence but after we perform the critical percent calculation, the monthly PM becomes priority.

Why is scheduled maintenance critical percent important? Unplanned maintenance is generally more expensive than planned maintenance so by performing your PMs on time or as close to on time as possible can help avoid any unscheduled breakdowns, repairs and downtime. This calculation is a simple way to determine which overdue planned maintenance items should be completed first. scheduled maintenance critical percent is easy to calculate but critical percent reports should ship with any good CMMS software package.

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