no open flames, but still flame heat. those are gas fired, but flame is contained.
open flame is not an problem by itself, its the open flame in conjunction with a failure in vapor or fluid ethanol handling that would be an issue.
there are ways of doing flame heating that are not open or inherently dangerous as others.
the above picture (thanks Jed) is a good example of a safer way to do flame heating.
the still appears to be gas fired, and water jacketed, but the flame is contained within a proper chamber, exhaust gasses ducted out.
this creates a draft for the air, and significantly reduces the chance of the flame spreading out into the distillery.