My beelab, where I also extract, is just a wooden 5 x 7m insulated house with screened windows and screened door. While honey spinning, I just keep the windows shut. Never had a bee in there.
They may fly around the lab, but they can?t get in.
Distance to the hives that are scattered over the land is 10 to 200m.
Just ensure you insulate well and seal any entry points. My lab has been built with that in mind.