All public schoolhouses, theatres, lecture rooms, churches and public halls where large numbers of persons assemble, if more than 1 story in height, shall be furnished with doors opening outwardly and hung in such manner as to afford the most convenient and ready means of safe and speedy egress. Any building having doors of egress that open outwardly as provided in this section may also have outer doors on the front that do not so open, if the outer doors are habitually kept open during the services or performances.