I'd like to know if there's an argumentation-/science-based recommendation regardless of the specific laws in different countries. Boundaries/parameters of my question:
- fire pit for making a(n open) camp fire with wood for <= 15 persons (max. 10 kg of wood burning at the same time) on the ground inside a stone circle
- building made partly or completely of wood (I guess that matters, so should be distungished in the formular in the answer)
- fire is watched permanently
The choice of the distance should avoid transmission of sparks to fire receptive parts of the house, e.g. exposed parts of the root framework. What would a fire fighting specialist/consultant, assurance specialist, etc. say?
 I've no idea how to measure fire energy emission, so I give this "dimension" for the beginning