There are two categories of work done by maintainers, namely, work that is expected and work that is unexpected or anomalous. Work that is expected is built into your work program, complete with work plans for assets regardless of maintenance policy, including “run to fail.” Your objective should be to build a work program that balances the cost and effectiveness of the work program, with the risk that the unexpected will either happen infrequently or with little consequence if it does.
Companies are said to be in “firefighting” mode when the work program must be abandoned due to the volume and severity of unexpected “fires” each day. This column describes initial steps in moving to a more planned environment, including key elements of a work program.
1. Asset hierarchy: The first step in developing a comprehensive work program is to establish a logical hierarchy on the CMMS for all of your assets. This includes parent-child relationships from the highest level down to individual components and even failure modes. For example, the highest level might be a particular building for facility assets, production line for plant equipment, vehicle for mobile equipment, and 40-mile highway for infrastructure assets. The lowest-level components might be a fire extinguisher in a building, motor in a production line, headlight assembly in a vehicle, or 30-foot road segment as part of a highway.
One of the difficulties companies encounter in defining the asset hierarchy is deciding what level of granularity is required. Should each floor in a building be an asset? What about each room? Is a door an asset or part? Determining how many levels in the hierarchy will depend on several factors such as:
- will be there be sufficient history collected for this asset to warrant the additional administrative effort
- could failure modes and cause codes defined at the parent level provide sufficient clues as to the history of lower level assets; for example, for the asset “exhaust system,” cause codes like “corroded muffler” and “corroded exhaust pipe” allow users to treat mufflers and exhaust pipes as parts not assets.
2. Failure tree: For each asset or asset group, the problem, cause, and action codes are identified. The more advanced CMMS packages present these codes as nested and hierarchical, allowing users to associate a short list of problem codes to a given asset, a specific list of cause codes only relevant to each of the short-listed problem codes, and a selection of action codes tied to each cause code. The failure tree forms the basis for analytics on the CMMS, such as root cause analysis (RCA) and Pareto analysis for troubleshooting and continuous improvement.
3. Asset master: Fundamental to any work program is a complete record of static information for each asset in the asset hierarchy. This includes tombstone data such as asset type, manufacturer, make, model, serial number, and date of installation. Most CMMS packages also allow user-definable templates for asset groups such as pumps, flooring, bridges, and forklifts. Templates can be used to describe assets using attributes relevant to a given asset group. For example, length, width, and wall thickness are typical characteristics of piping, as opposed to horsepower, current, and speed used to describe motors. The asset master should also contain any relevant attachments including drawings, manuals, and videos.
One of the most important fields on the asset master is “asset criticality.” Some CMMS packages use a sophisticated scoring algorithm to generate criticality, while others use a single-digit, user-definable drop-down, ranging from low to high criticality. The asset criticality is essential for prioritization when planning, scheduling, assessing risk, and determining areas of focus for continuous improvement. For example, when creating a work program, always start with the most critical assets.
4. Parts master: Once the asset hierarchy and asset master have been determined, a standard bill of material for each asset is defined. This includes parts that will be:
- catalogued and kept in inventory with a specific minimum quantity, reorder point, reorder quantity, preferred supplier, lead time, and cost
- catalogued but not kept in inventory
- not catalogued but referenced on the CMMS — for example, link to OEM or an attachment on the asset master.
As with the asset master, all tombstone data for catalogued parts are defined, such as part name, description, and serial number, if relevant, as well as template-based attributes relevant to each parts group like belts, bearings and switches.
5. Maintenance policies: There are only three ways maintenance work is triggered as follows:
- use-based maintenance (UBM) — triggered by meter (for example, every 3,000 miles), time (for example, every three months), or an event (for example, every snowstorm)
- condition-based maintenance (CBM) — triggered by condition of the asset assessed through automated, semi-automated, or visual inspections, (for example, pressure exhibits certain trend characteristics or hits an upper/lower control limit)
- fail-based maintenance (FBM) — triggered by failure of the asset (run to fail).
For each asset, perhaps for each failure mode for the more critical equipment, you must determine the maintenance policy that best balances risk in terms of probability and impact of failure, with asset lifecycle cost, performance, reliability, availability, and quality of output. The CMMS can be used to analyze equipment history in determining optimal maintenance policies. Other sources include industry data, consultation with the equipment manufacturer, and experimentation. Some CMMS vendors or third-party products offer the more rigorous reliability-centered maintenance (RCM) techniques for determining the most appropriate failure modes, failure effects, and maintenance policies.
Note that optimal maintenance policies may change over time, for example, when equipment degrades, new inspection equipment/techniques are developed, or analysis of asset history or experimentation identifies improvement potential.
6. Work plans: Drafting meaningful work plans is crucial to the success of your work program. Work plans set the standards for how your maintenance policies will be implemented across the enterprise, including allowable local deviations. Work plans should be defined on the CMMS and either auto-populate work orders when maintenance is triggered or are attached. Work plans for all three maintenance policies should include:
- standard procedures
- safety procedures (permits required)
- standard materials required
- special tools and equipment required (crane)
- standard skills required (minimum of two certified electricians)
- asset downtime requirements (three-day outage)
- standard labor hours
- quality standards
- any attachments such as drawings, tables, detailed descriptions, videos
- maintenance frequency for UBM (every 2,000 hours of operation)
- inspection intervals for CBM
- relevant checklists (for entering readings for inspections)
Work plans can also be logically grouped into a work breakdown structure for a major maintenance or plant shutdown.
7. Budget: The total cost of the work program can be calculated using advanced CMMS packages by extending standard labor hours and material requirements from work plans. Other line items in the work program cost summary should include:
- non-maintenance work based on history and future expectations (capital projects, demand work like moving a wall)
- non-maintenance activities (training, travel, cleanup)
- cost implications of capacity planning (overtime, contractors).
However, this is the cost from the asset’s perspective. Suppose management expects a 10% decrease in budget next year. The more comprehensive CMMS packages allow simulation capability, in order to evaluate the change in risk and cost when adjustments are made to the labor and material standards. For example, what is the impact if we mow the grass less often, relax our quality standards, switch to FBM on redundant or less critical equipment, streamline our safety procedures, improve scheduling to reduce travel time, or start kitting parts to reduce wait times?