In my basement I have several lolly columns attached to wooden beams that are supporting the floor joists. On one of these wooden beams I have attached a smoke detector vertically on the side of the beam instead of at the bottom of it, mainly to avoid someone knocking the smoke detector with their head since there is low clearance. The detector is next to the lolly, not directly over it.
Here's a 2D picture (not to scale):
I can mount the smoke detector to the joist in the typical horizontal ceiling type of fashion, but is it OK to mount it vertically? Will its effectiveness be reduced or compromised?