I’ve seen B and SB (basement and subbasement) on elevator buttons. Generally those are floors that the public isn’t allowed to go to and I never had the right key to activate them so I don’t know what was there.
I’ve also seen B1 B2 B3 B4 B5 for different basement levels, though I don’t remember which was on top. Those were all parking levels though so no rooms were numbered.
I’ve seen B and SB (basement and subbasement) on elevator buttons. Generally those are floors that the public isn’t allowed to go to and I never had the right key to activate them so I don’t know what was there.
I’ve also seen B1 B2 B3 B4 B5 for different basement levels, though I don’t remember which was on top. Those were all parking levels though so no rooms were numbered.
Basements are numbered increasingly as they travel away from the ground floor. This is code for elevators at least, in most municipalities in the US.