It may be that it is only practical ( physically achievable and cost

effective) in certain situations.
Which was why I was interested in the fundamental research.
  Consider an all weather-board house I visited in Belgrave ( in the
middle of winter);
which  had state-forest  with 30m gums and heavy undergrowth within 10m
of the back of the house;
I suspect the radiant flux from a crown-fire there would heat the air
inside so rapidly it would almost explode !;