In order that satisfactory results may be obtained from an open
fireplace, it is essential: First, that the flue have the proper area;
second, that the throat be correctly proportioned and located; third,
that a properly-constructed smoke shelf and chamber be provided; fourth,
that the chimney be carried high enough to avoid interference; and fifth,
that the shape of the fireplace be such as to direct a maximum amount of
radiated heat into the room.