Deck/stair conundrum

I know, I know – not ANOTHER deck post! But I’ve been lurking around on the many posts about decks and have what may be a dumb question about the minutiae of DOB codes: do all of the codes relating to noncombustible material etc etc apply if I simply want to construct a stairway from my parlor floor kitchen to our backyard garden? I currently have a (probably illegal) wooden deck that is falling apart, so trying to figure out how to rebuild something much simpler – just a straight shot down and out of the back kitchen door. I am unsure whether I need to get an architect/pull permits/build with steel for a simple staircase…. seems like overkill?