852 $b - Sublocation or collection:

Subfield $b contains the name of the organizational division of the organization (identified in subfield $a) or the name of the collection in which the item is located or from which it is available. The name is given in full or in a standardized abbreviated or coded form.

Subfield $b may be repeated to indicate the organizational hierarchy of the sublocation. Separate 852 fields are used for each sublocation when multiple copies of an item having the same call number are housed in various sublocations or when parts of a copy are split among several locations. Example: