The walls and door of the stairs inside the building must be made of fire-resistant materials and does not cause the smoke, such as reinforced concrete walls. Refractory masonry, etc.
The walls and doors of a building fire escape must be made of fireproof material. And does not cause smoke, such as reinforced concrete walls. Masonry, refractory etc.
Walls and doors of the elevator inside the building must be made of refractory materials and does not cause smoke, such as reinforced concrete wall, brick wall, fireproof. And so on.