how do you fireproof a stairwell?

Question

why?

Answer 1

Stairwells are designed egress for stories above the first. They are fireproofed (on both sides of the wall) to keep this main egress open in event of fire.

How do you fireproof an existing a stairwell? If it is constructed of masonry walls and steel stringers/ platforms along with fire rated doors, the job is already done. All pass through items (sprinkler pipe or conduit) must be caulked with fire rated caulk.
If you are speaking of wood construction, 5/8 drywall encasing the entire stairwell, with no bare stringer to stud (or platform) connections and fire rated doors will give 1 hour protection.

Answer 2

The building codes are based on getting people out of a building in an emergency. this includes all halls and stairs that lead to the outside.

The stairwell is fire rated and not really fire proof. fire rated means that it can keep a fire out for some specified time like one hour/ two hours/ three hours depending on any number of factors such as how many people will be using it (auditoriums and schools have more stringent requirements than a storage area).

Fire rating are attained by using materials of construction that can hold out a fire. Cement usually gets high ratings/ wood is not allowed. Doors are usually metal or specialty fiberglass. Windows are tempered fire rated glass. any pipes or conduits must also recieve special attention in the application of intumescent sealing materials.. they expand as they heat up closing off and gaps where heat or smoke could enter the stairwell.