Exit doors open outwards to allow large crowds of people to exit rapidly in a case of a fire. Inward-opening doors have been outlawed in the US due to a horrific fire incident which killed 490 and injured 166.
On November 28, 1942, The Cocoanut Grove restaurant in Boston, Massachusetts caught on fire. As patrons rushed out of the entrance, the revolving door jammed due to the influx of people. “Observers outside could only watch in horror as relatives and friends were crushed by the weight of the crowd surging against the jammed door.” Remaining patrons attempted to exit through an emergency exit. “However, because the door was installed as an inward-opening door, the rush and weight of those fleeing the fire caused the door to shut, cutting off an important escape route.”
“Building codes were amended in the city and elsewhere. Revolving doors were outlawed (later reinstated when a revolving door is placed between two outward-opening exit doors). Exit doors were to be clearly marked, be unlocked from within, and free from blockage by screen, drapes, furniture or business supplies.”
Source: Boston Fire Historial Society