A: It works from inside our barn, which has steel roof and siding. I wouldn't recommend it for a completely enclosed steel building, but if it is just the roof you should be good. If an AM radio can pick up a signal (the system monitors electrical noise in the AM radio band), you are good to go.
A: The user guide says that the device needs to be near a window (within 3 ft). There may be buildings in which the antenna in the tornadoAlert device is shielded from receiving the energy from a storm, such as in a basement or bunker. I am not sure about a steel roof. In other instances, such as houses with radiant barrier in the attic, or metal roofs, the device performed as expected. I would say give it a try. My experience has been that the device works amazingly well. Never have I gotten a false alarm. Always detects the severe weather in the area. Accuracy, both in terms of distance of the storm and severity, is almost always dead on. Everyone should have one of these to ensure awareness of approaching storms.
A: There are actually 5 levels of detection (6 counting "No Threat"). From least severe to most severe: 1 Lightning 2 Not Severe (Thunderstorm, but not at Severe Thunderstorm damage potential) 3 Severe Thunderstorm 4 Tornado Risk (tornadic thunderstorm that could produce a tornado soon) 5 Tornado I have found that it is VERY effective at differentiating the severity levels all the way to the extent of the 30 mile range around the device.
A: It reports lightning, storms, severe storms, tornado risk, and tornado. For each of these the bar graph indicates the distance (more bars means closer). I've owned this for nearly a year and have found it quite accurate and sensitive, and even better than the city's weather sirens.
A: Yes, it will distinguish between lightning, severe weather or tornado.
A: It has many levels. Mine has determined lightning and desplayed the word lightning on the screen. However, during a recent tornado warning of rotation that did not touch down, it detected a "not severe " storm and displayed those words. More testing during actual weather events needs done before I can reccomend this product.