One of the first tasks for firefighters arriving at a blazing home has long been to ventilate the structure — make holes in it — so that hot gases and smoke can escape. It has been this way for generations: a so-called roof man from a ladder company opens a hatch or saws through the ceiling, while other firefighters break windows as they search inside, often before the first drop of water has hit the fire.

But house fires have changed. Now, spurred on by at least one grievous injury to a firefighter last year, the New York Fire Department is rethinking its tactics for residential fires, while trying to hold onto its culture of “aggressive interior firefighting” — charging inside burning buildings as fast as possible.

As it is the largest municipal department in the country, its new course may well affect the tactics of other fire departments.

“We’re an organization steeped in tradition and we’ve been fighting fires for many years in certain ways and they worked,” the fire commissioner, Salvatore J. Cassano, said in a phone interview.