Here's a silver gelatin image just in to the Evermore Gallery of American Art's Image Collection. It's from 1940. Professionally produced it's size is the classic 8" x 10"

The men are using warm water to remove ice on the building from the 86th floor (Observation Deck). Even the ladder says "86th Floor Porter"

I would have to assume that all floors were provided a ladder. Go to the Evermore Image Collection for more original photographs.