Every hotel in this State over two stories in height shall be provided with permanent iron balconies with iron stairs leading from one balcony to the other, above the ground floor, and with a stairway or ladder extending to the ground, in case such hotel is over one hundred and fifty feet in length and in other cases such number as may be directed by the State Fire Marshal of South Carolina or his agent. But when hotels were built prior to March 6, 1920 and are, in the opinion of the State Fire Marshal of South Carolina or his agent, provided with sufficient inner stairways, so located as to furnish sufficient egress in case of fire, the State Fire Marshal may waive the requirement for outside iron balconies and stairs. Such balconies and iron stairs shall be constructed at the expense of the owner of the hotel. This section shall not apply to hotels built prior to March 6, 1920 where fire escapes are located so as to go through any room.