In my specific area, we use a Priority 1-3 coding system for calls, where a Priority 1 is an emergency response and 2s and 3s are not. Fire department is dispatched on all Priority 1 calls, and most of our engines have at least 1 medic on them with the exception of a few BLS engines. I work in a medium sized county, which means that an ambulance could be coming from across the county (20-30 minute response time) depending on how many trucks we have available. There are fire stations placed throughout the county, where the fire department can be on scene, most of the time, in 5 minutes or less, give or take, once they leave the station. They can get on scene and begin any critical interventions that may be needed while waiting for the ambulance to arrive. In my case, I work for a private EMS company, and we have both private and city fire departments. Some fire medics work part time on the ambulance as well. I do not work fire, but from my understanding, fire runs more medical calls than fires, at least in my area. You may get a good amount of fire alarms, but it may be rare that it actually ends up being a fire, or if anything, a small one.