A loft is a very handy kind of space, with practically no restrictions attached. Typically, these spaces are free of furniture, so you can bring your own and set it out as you please. As a rule, lofts have high ceilings which measure at least 4 metres. Many of these venues are located in industrial zones, on the premises of former factories and warehouses. This should mean that you are free to play loud music and dance.
Dance is about movement. The venue for this kind of event should be spacious enough that everybody participating can feel free and not have to worry about bumping into one another. You might want to check whether it includes a changing room, shower, and toilet.