The faces of four real-life Bravest will be smiling from the facades of every firehouse in the city on Monday — part of a new recruitment tactic put in place by the Fire Department. For the first time ever, banners will be draped across firehouses in an effort to encourage potential new recruits to sign up for the firefighter entrance exam this spring. Filing for the test — the first step in the long process of becoming a city firefighter — opens on April 5, the Fire Department said. The four Bravest who were chosen to be the poster faces of the FDNY are all active-duty firefighters who also serve as recruiters for the agency.