There are two ways to specify an inspection: implicitly and explicitly. Both are used in preventive maintenance (PM), and both are appropriate at different times. To start, let’s review the definitions.
Explicit: In a clear and detailed manner, leaving no room for confusion or doubt. The explicit inspection description will have detailed items to look for, have standards or ranges (such as running amps under load: 50-70), and may include photographs and drawings.
Implicit: Implied though not plainly expressed. The implicit inspection description has few words and, if any, drawings will be very general.
An implicit list either requires a technician to have significant experience with the specific equipment or has only superficial requirements. The implicit list is a general reminder.
Technicians working on construction equipment using lists such as the one illustrated in Figure 1 typically follow a protocol they were taught or personally developed through years of experience. The issue with this type of list is that each person using it may perform checks differently.This is okay when the intent is to sweep through an area to look for obvious faults. In an example of this usage, a building tenant might be required to perform a monthly inspection of their building’s basement for water, visual mold, and natural gas or sewer smells. In that type of task, the implicit list is fine. The intent was to get someone to enter an area and observce with their eyes, ears, and nose. This type of inspection is more of a security sweep through an area than a detailed look.
Explicit tasks, on the other hand, require necessary detail. PM checklists should provide enough detail that new technicians can realistically complete the task by following the list. Provide them with photos or diagrams; inspection checklists should include visual representations of the instructions to make the job easier and clarify any ambiguity. While details are important, explicit task lists should also be as concise as possible. Every task on an inspection checklist should have an explicit action and goal associated with it to ensure maximum efficiency.
According to Fiix (a Rockwell Automation Company), PM checklists create a standard method of performing tasks, which leads to reliable outcomes. There is no guesswork or miscommunication, reducing the chances for an error.
A senior technician might be annoyed by a detailed and explicit list because it seems to discount their expertise; it might seem petty to them. But, if followed, the list ensures that everyone performs every task the same each time.
Without explicit tasks, changes such as PM optimization are very difficult to implement because each technician may be doing things their own way.
When designing inspection, tasks keep the goal in mind. If you expect to pick up specific failure modes, you will have to look for them. If you want to avoid gross failures, developing an implicit list will be fine.
An example of an implicit task would be: “Check tires.” Most technicians will know to look for apparent defects or deterioration like baldness or sidewall damage. Here we are making immediate safety checks.
An example of an explicit task would be: “Measure tread depth and individual tire pressure and records. Look for uneven wear patterns.” Here we are trying to improve tire life and fuel efficiency and do a safety check.
Whether it is appropriate to use explicit or implicit tasks depends on the ultimate goal.
Joel Levitt is the president of Springfield Resources, a management consulting firm that services a variety of clients on a wide range of maintenance issues. Levitt has trained more than 17,000 maintenance leaders from more than 3,000 organizations in 38 countries. He is also the creator of Laser-Focused Training, a flexible training program that provides specific, targeted training on your schedule, online to one to 250 people in maintenance management, asset management, and reliability.
