Definition
The components of a technical object are located in the items of the BOM. Item data is only valid for a particular item within the BOM.
Structure
Items are differentiated by their category (). The item categories are differentiated by an item category key.
Further important item indicators are
Item Category
This item category applies to components which are kept as stock. Any components entered with this category in the BOM must have a valid master record in the system.
When you use this item category, stock item components are automatically reserved for the maintenance order.
This item category is used for components which are not kept in stock if they are used in a bill of material (BOM). Non-stock items can be entered in the BOM with or without a master record. To enter a non-stock item without a master record, you must simply enter a descriptive text.
When you use this item category, the system automatically creates a purchase requisition for these components, when they are used for maintenance purposes. This leads to order-specific materials procurement via the purchasing department.
This item category enables you to specify different sized sections of a component with one material number. Variable-size items are distinguished by the fact that format entries, such as length and width, are taken and converted into the quantity required for warehouse management purposes.
When you use this item category, variable data, such as the size of a steel sheet required to repair some planking, can be entered directly by the user during order processing. You do not have create new material master records with fixed dimensions in the system each time.
This item category is for components which contain information stored as documents. A document can be a design drawing, program, photograph and so on.
When you use this item category, the bill of material (BOM) is connected to the document management system.
When you use this item category, the system stores your text in a text file using the long text processing function.
This item category is for components in plant maintenance which are only used for structuring a technical object (PM assembly). No plant data is necessary for this item.
This item category is only used in plant maintenance for equipment and material bills of material relevant to plant maintenance.
The class item enables you to create a class as the components in a configurable bill of material (BOM for a standard product). Several objects can be allocated to this class, and differentiated by different characteristics.
You can find further information relevant to variant configuration in the SAP documentation PP- Variant Configuration.
Item Category Key
The different item categories are represented by a letter key in the standard SAP System:
L stock item
N non-stock item
R variable-size item
D document item
T text item
I PM structure element
K class item
As the letters of an item category key are defined in Customizing, you can adapt the letters accordingly.
Item Status
For a BOM item, you must specify whether it is relevant in a construction or plant maintenance context, for example. In other words, you must specify in the item detail screen whether it is relevant to construction or to plant maintenance. For a BOM of application type Plant Maintenance, the status "Plant Maintenance" is automatically set by the system in this screen. This cannot be modified. Depending on how the BOM usage was set, you can change - among other things - the entries in the following two item status fields:

Indicator |
Meaning |
A |
spares relating to safety, must always be at least two available |
B |
spare part widely used in the company |
C |
spare part rarely used |
Data relevant to Plant Maintenance
The indicator "PM assembly" is maintained in the data section maintenance relevant data. This indicator can only be maintained when the BOM usage allows the item status "maintenance".
If an item is indicated as a PM assembly, then it will be displayed as a component of a technical system when maintenance tasks are processed. You can use an item which is indicated as a PM assembly to describe an item in more detail. For example, because the maintenance work has to be carried out just on this assembly in a technical object. The assembly can also be used to locate damage more precisely.
Bill of Material Sub-Items
Bill of material (BOM) items can be divided into sub-items for better data management. Sub-items can be used, for example, to divide an item if partial quantities of an item have different installation points. The sub-items can be used to depict these different installation points. You can maintain a short text and a quantity for each sub-item in addition to the installation point.