How You Model Maintenance Work Definitions

When you translate an asset service interval into a work definition, you review the originating service tasks and determine how work definitions should be defined into a unique and logical sequence of steps.

Based on the service interval definitions, you can model work definitions using one of several approaches:

Unique Work Definitions: contain all the steps required to perform a task
Incremental Work Definitions: contain all the steps required to perform a task based on the combination of operations from an existing work definition plus incremental additional operation steps.
Add-On Work Definitions: contain only the incremental steps to perform specific task. It is expected to be combined with another unique work definition during the creation of a work order.

Unique Work Definitions

Create these types of definitions to represent the complete set of steps for a task. You can used these work definitions as the work scope for the manual creation of a work order or in a work requirement.

However, these types of work definitions are typically not expected to be combined with other work definitions in a work order, as it would result in duplicate operation steps. Therefore, if used in a work requirement, they typically aren't modeled to merge with other work definitions.

For example, a work definition for an oil change that's due every 5,000 miles for a truck. This work definition includes all the steps to:

Inspect the truck
Drain the existing oil
Remove and replace the oil filter
Fill the new oil
Run the engine and check for leaks

Incremental Work Definitions

Create these types of definitions to represent the complete set of steps for a task that's based on an existing work definition plus additional steps. You can use these work definitions as the work scope for the manual creation of a work order or in a work requirement.

These types of work definitions are typically not expected to be combined with other work Definitions in a work Order. However, they could be defined in a work requirement with other work definitions, representing the unique work that's required at a unique interval in a cycle-based forecast.

For example, a work definition to replace the air cleaner every 10,000 miles for a truck. This work is executed at the same time as the oil change. Therefore, this work definition includes all the steps to change the oil and replace the air cleaner in a single work definition:

Inspect the truck
Drain the existing oil
Remove and replace the oil filter
Fill the new oil
Remove and replace the air filter
Run the engine and check for leaks

Add-On Work Definitions

Create these types of definitions to represent only the incremental set of steps for a task. You can only use these work definitions as the work scope in a work Requirement where it's expected that they would be merged with a unique work definition, typically at an interval in a cycle-based forecast.

The unique work definition would contain the common steps that don't need to be repeated in each of the other add-on work definitions.
The add-on work definitions would define additional steps to be added and it's expected that the work definitions would be merged into a single work order

For example, create these types of work definitions that work together in a work requirement:

Every 5000 miles, the engine oil and filter require replacement (unique Work Definition)
Every 10000 miles, the engine air cleaner element requires replacement (Add-On Work Definition)
Every 25000 miles, the engine's accessory belts require replacement (Add-On Work Definition)
Every 50000 miles, the transmission fluid and filter require replacement (Add-On Work Definition)
Every 75000 miles, the brake pads and rotors require replacement (Add-On Work Definition)

During work requirement modeling, work definition 1 would be due every time a work order is created. Then, starting at 10,000 miles, additional add-on work definitions would be merged with the work definition 1 to create a unique work scope in the work order for the Asset. While this modeling may seem a little more complicated, it does provide some flexibility for preventive maintenance modeling over time.