The OP is misleading you. You don't need to reach melting temperature to affect a steel structure - you can weaken the steel and produce strange unplanned loads at lower temperatures and cause failure cascades.

Here is the NIST story about WTC7: https://youtu.be/PK_iBYSqEsc

Myles Power made a video about WTC7: https://youtu.be/7PpsCCTMP8w

I don't endorse him on other topics, but this particular video is good.

The OP is misleading you. You can run up a furnace to very high temperatures just by having a hole that air rushes through (with a fan, or wind). You don't need to reach 2700 to affect a steel structure - you can weaken the steel and produce strange unplanned loads at lower temperatures and cause failure cascades.

Here is the NIST story about WTC7: https://youtu.be/PK_iBYSqEsc

Myles Power made a video about WTC7: https://youtu.be/7PpsCCTMP8w

I don't endorse him on other topics, but this particular video is good.