I’d be curious exactly what their regulations say. You can buy fire escape ladders for very little, under $100, though I’m not recommending that.
In our jurisdiction we just need two exits from each room, one of which can be the window. But there are laws here on how high that window can be and its dimensions.
I did look into providing something more. I talked with someone at our fire department and they advised against those chain/rung ladders that just sort of hang and for which you need to get your feet into while they’re loosely hanging.
Much better, she said, are those that have ‘standoffs’ that stay against the wall so that you can easily get your feet into them.
The truth is that you can likely comply with the letter of the law for not much money, like in the hundred dollar ballpark per room. You might/might not be interested in how truly effective such a fire ladder will be and how much more will it cost to install something that people can more easily use.
So, 1) Do you just wish to comply with the law (no judgments)? or 2) Are you looking to provide something that is easy to use?
I recommend Googling home fire escape ladders to read up on this, and talking with your fire department on anything they might recommend or recommend against. They’re unlikely to point you to a specific product but might give you their thoughts on do’s and dont’s or at least pro’s and cons… You might also talk with your insurer for any thoughts they have, if any.
I assume that you’ll also need to provide a ‘map’ on each bedroom door that shows the primary and alternative evacuation paths. It can be useful to provide additional instructions, like feeling the door for heat before opening it, where/how to use the ladder, etc.
At one point I was considering this (~$500): Fire Escapes Systems - Offering a Complete Line of Portable Chain/Rung, Rigid Aluminum and Fixed Fire Escape Ladders