system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: If large buildings are made of concrete, shouldn't they be able to build it so a fire can't spread from one floor to another?

As has happened with the london tower block fire for example.
gpt
They do. The big, heavy steel doors to the stairways that close automatically are designed to keep the fires from spreading from floor to floor. That's why bldg security goes apeshit when they're propped open or the hydraulic closer is broken or disabled.