All the doors for ingress and egress to and from all public schoolhouses and all other public buildings, and also of all theaters, assembly rooms, halls, churches, factories with more than twenty employees, and of all other buildings or places of public resort whatever, where people are wont to assemble, excepting schoolhouses and churches of one room and on the ground floor, which shall hereafter be erected, together with all those heretofore erected and which are still in use as such public buildings or places of resort, shall be so hung as to open outwardly from the audience rooms, halls or workshops of such buildings or places; provided, that said doors may be hung on double-jointed hinges so as to open with equal ease outwardly and inwardly.