In our hallway and in a couple of other rooms in our home, we have combination fire detectors and carbon monoxide alarms made by a company called FIRST ALERT. Its purpose is to alert you to any potentially dangerous or hazardous situation that you may not be unaware of in your home otherwise. It is designed to notify you and maybe even save lives.
Have you ever received an AMBER ALERT? That is a mass communication to alert people to the fact that some child has gone missing and to be on the lookout (BOLO) for a particular individual or a particular vehicle. This alert is designed to notify others that there is a potentially dangerous situation occurring. It also is designed to inform and maybe even save lives.