A collection of associated control modules and/or equipment modules and other process equipment in which one or more major processing activities can be conducted.
Units are presumed to operate on only one batch at a time. Units operate relatively independently of one another. This term applies to both the physical equipment and the equipment entity.
Examples of major processing activities are react, crystallize, and make a solution.
Typically Process Descriptions may be written for each unit type
It is not always a simple matter finding the Units. Often, specially in multipurpose plants or where CIP is involved, units are dynamic - that is that their boundaries can change (for example by acquiring or releasing equipment modules) during the execution of a recipe.