XREF (Background) Files
9 characters maximum (not including filetype extension)
Standard: XPPA-DTTLL
X PP A(-) D TT LL
X: Identified the file as a Model file to be XREFed to other files.
PP-: Project identifier (2 characters) (Optional)
A: Phase identifier (Optional) (1 character or “-“ (hyphen))
D: Discipline (1 character)
TT: File type (2 character)
LL: Floor/series identifier (2 character)
Examples:
XPC-AFP01.dwg
Pima County, Architectural, Floor Plan, First floor
XPC-CSP01.dwg
Pima County, Civil, Site Plan, #1
XS8ACSP01.dwg
Segment 8, Phase A, Civil, Site Plan, Mainline (#1)
XAFP01.dwg = Arch Floor Plan, First Floor (No Optional characters)