Penn State does numbering that way also. (I'm posting and example and hpe this matches what you are asking) I'd like to know the same
Room J002
Has door J002a, J002B
Ustn since 1988SS4 - i7-3.45Ghz-16 Gb-250/1Tb/1Tb-Win8.1-64bEric D. MilbergerArchitect + Master Planner + BIMSenior Master Planner NASA - Marshall Space Flight CenterThe Milberger Architectural Group, llc