The Equipment Library contains a hierarchy of equipment classes. Each piece of equipment has a parent in the hierarchy (except for the equipment base class) from which it inherits attributes as well as the rules for geometry, nozzle placement, and vicinity routing. Additional attributes can be added to the equipment class and all the rules can be edited. The Equipment Base Class acts as the master parent class. Because all rules and attributes are passed to children classes, the base class has no rules and on the Allowable Nozzle Types attribute. You can add attributes to this class and are cautioned that those attributes will then be passed to the rest of the library.

As shown in the above figure, the PlantWise Equipment Library has two primary branches from the Equipment Base Class. One for rectangular equipment (with length, width, and height attributes) and the other for cylindrical equipment (with diameter and length attributes). Other classes can (and do) branch form the Equipment Bass Class; therefore, you are not required to branch from the Plain Box or Cylinder.

The Equipment Library contains definitions for each equipment class. Each class has its own set of attributes, geometry rules, nozzle placement rules, and vicinity routing rules. These rules define how the equipment looks - including service spaces; how nozzles place on the equipment; and how pipes enter and/or leave the equipment. You can add classes as well as edit existing rules.

The process of defining new types of equipment goes through the following steps: