This video shows several firefighters entering a structure during a controlled training burn. Several firefighters enter the structure without a hose line and advance forward. Smoke conditions slowly begin to worsen and soon show rapid signs of a flashover when the PPV fan is placed inside the front door. The house flashes, firefighters quickly work to get out of the building, and the PPV fan was instantly removed. Fortunately, all firefighters were wearing full protective clothing which lead to only one small minor burn.