ASHRAE 90.1 Space by Space Method - Office, Enclosed or Open Plan

I would assume that enclosed offices have a door to them while open offices don't really have a door except to enter the space itself from a corridor or something similar. An open office space also tends to have systems furniture and multiple occupants in the space while an enclosed office would typically have one occupant. There could be some grey area here so use your best judgement. If you are not sure you will want to be conservative by selecting the space type with the higher LPD.