Paragraph 7 2 1 5 8 9 from nfpa 101 says that roof doors have to either allow free egress from the roof or be kept locked.
Roof slope fire egress.
Lapped nonsoldered seam metal roofs without applied lap sealant must have a minimum roof slope of 3 12 25 slope.
I interpret this to mean that if the door is locked on the stair side preventing free access to the roof it does not need to provide free egress from the roof.
Roofs with slopes greater than 10 degrees and up to 30 degrees will require additional anchoring.
Low or no slope roofs up to a 10 degree pitch can be installed without the need for any additional anchoring other than what is found in a flat roof system.
Most states and townships have building codes that require means of egress on each floor sometimes including finished basements and attics.
For example a fire escape is defined as a means of egress because it s a way for someone to exit a building in an emergency.
A single exit or access to a single exit shall be permitted from any story or occupied roof where one of the following conditions exists.
The minimum roof slope for metal roof panels depend on 3 different scenarios.
Emergency exits on these floors usually come in the form of egress windows.