five or six minutes after paul camiolo called the fire department the outside window exploded. the explosion was the result of what is called flash-over. when flash-over occurs, temperatures in the room get so high that items ignite even without coming into contact with the flame, as you can see here. >> and in fact, unfortunately there are firefighters killed every year by having been caught in flash-over conditions because it happens so rapidly. sometimes it's very difficult to escape from those conditions. >> after roby entered this information into his computer program, he lit a virtual match. within 30 seconds, hot gas fills the room. within one minute, smoke and gas spread up the stairs to the second floor. and three minutes after ignition, the living room would reach flashover, blowing out the