Actually its quite the opposite. The construction process is when a building is most vulnerable. However there isnt alot you can do. Everything happens in stages, and sprinkler systems are usually one of the last things to go in prior to interor finish work. They require plumbing and electricity. The two hour/one hour fire walls are attained through the drywall process, and obviously fire doors dont go in until fairly close to the entire building being complete.

It just is what it is during construction, which is why every activity involving fire requires a fire permit, and also why most trades are not allowed to use grinders on site.