A fire-rated door is not supposed to combust during a certain time frame While time ratings vary 20- to 90-minute.
Fire doors are required to be equipped with a fire-rated frame and self-closing hinges
- The Minimum thickness for a fire-rated door is 1-3/4”
- The door and frame both must have 20 Minute Label
- Typically add $$ for adding a Fire rated frame to the Single door
- you may search for fire rated door
- here is a link to Fire-rated Doors