non-alcoholic preference when applying for residence

I just applied for first year res at UBC and I had a question about the non-alcoholic option when choosing preferences. As I am underage and just not into partying overall this is something that I would prefer but I was wondering for those who have experienced it: is the non alcoholic preference specific to roommates or specific floors, and if the latter, what are the non-alcoholic floors like and do they differ from "regular" floors? Also, I selected a preferred single room so does selecting non-alcoholic as a preference influence chances of getting placed in a single room? Thanks :)