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:
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Unique Work Definitions: contain all the steps required to perform a task
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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.
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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:
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Inspect the truck
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Drain the existing oil
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Remove and replace the oil filter
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Fill the new oil
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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:
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Inspect the truck
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Drain the existing oil
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Remove and replace the oil filter
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Fill the new oil
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Remove and replace the air filter
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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.
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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.
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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:
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Every 5000 miles, the engine oil and filter require replacement (unique Work Definition)
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Every 10000 miles, the engine air cleaner element requires replacement (Add-On Work Definition)
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Every 25000 miles, the engine's accessory belts require replacement (Add-On Work Definition)
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Every 50000 miles, the transmission fluid and filter require replacement (Add-On Work Definition)
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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.