by Arne Oas

Operations supervisors are upset. Each of them wants their work done first regardless of what it is. Critical maintenance work is delayed or missed. Other work in the CMMS is so old, no one remembers if it has been done or just forgotten. Your backlog is growing and is out of control. What do you do first? How do you prioritize?

In order for a maintenance department to be truly efficient and effective, its work must be planned, scheduled and performed in some order of importance to the facility. Work type and equipment criticality are two key areas for development in a CMMS.

The work type code is often called a priority code and should be based on the nature of the work, (emergency, preventive, predictive, etc.). The location/equipment criticality code is established based on the unit’s relative importance to production or operation of the site (key unit shuts down line, plant, etc.). These two values are then multiplied together (beware: different systems use different formulas) to arrive at a Relative Importance Factor (RIF), or the order of service. This computed result is then evaluated by the planning and scheduling process and changed as required.

With only slight modification, the following tables are used in many different systems.

PRIORITY

1) Safety/life and limb: Needs to be completed above all else.
2) Environmental: Needs to be completed immediately.
3) Emergency: Needs to be completed immediately
4) Critical: Needs to be completed within 24 to 48 hours.
5) Preventive maintenance: Completed as scheduled.
6) Routine: Can be scheduled for completion at a future time.
7) Project Work: Long-term planning.
8) Housekeeping.

CRITICALITY

1) Affects plant personnel or the environment.
2) Shuts down the entire plant.
3) Shuts down an entire department.
4) Shuts down an entire line.
5) Restricts the full performance of a department or line.
6) Shuts down a vital piece of equipment but does not affect the plant, line, etc. This equipment usually has a backup.
7) Shuts down a non-vital piece of equipment.
8) Building work.
9) Mobile equipment.
10) Other (i.e., office equipment).

Calculating a RIF
Applying these tables, an emergency request (Priority 3) on a piece of equipment that would shut down a line (Criticality 4) would give the work a RIF of 12 (3 x 4). A critical (4) job that shuts down a vital piece of equipment (6) would result in a RIF of 24 (4 x 6).

Depending on the CMMS, the highest or lowest number could be most important. In this example, the lower RIF number (12) would be more important and scheduled first.

The facility’s planning and scheduling function can then review the resulting work list showing these RIFs. New work orders coming in with RIF codes 1 to 16 should be reviewed and scheduled daily or immediately, usually with minimal formal planning. The remaining work orders are placed in the backlog to be reviewed by the planner.

The review should check for parts, manpower availability, equipment availability and overall importance. This will ensure that the time required and parts required for critical jobs were evaluated and that everything is available. During the review, the RIF of a work order could, of course, be changed due to additional information (a change in machine condition or status) or office politics.

The last part of the scheduling piece (usually not included in CMMS RIF calculations) is the age of the work order. All other things being equal, the oldest work order should be done first.

This article appeared in the April/May 2003 issue of MRO Today magazine. Copyright, 2003.

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