What does this mean in the real world? Well, it's almost impossible for a fire station to cover more than 10 square miles and still have firefighters arrive at incidents within the time constraints that many of us consider appropriate for structural fire response. Therefore, if you have a fire station that protects more than 10 square miles, there are going to be lengthy response times.

Another attribute is financial stability. Fire departments are not free. They cost money, even volunteer fire departments. I know of no fire department that hasn't moved past the bucket brigades of the 1600s. To purchase a piece of fire equipment, whether used or new, requires someone to raise the money. Although volunteers may not be paid for their time, they still have to be protected with liability insurance and workers compensation. Full-time paid firefighters working in a fire station have a cost factor that is reasonably predictable and directly linked to policy decisions that determine how many people are on individual engine companies.

The combination of these financial factors leads us to the idea that there's a minimum amount of money needed to operate a volunteer or full-time fire company. Somewhere in between are combination fire companies that somehow emerge from the former and eventually disappear into the latter. Most volunteer fire departments will remain volunteer as long as their workload fits reasonably within the lifestyle of their volunteers. The minute you start asking them to go to more calls than they can fit within their existing commitments, they begin to disappear.

Because such an increase in calls is most often the result of an increase in population, we're left with the conclusion that almost all communities with fewer than 10,000 people, regardless of how much area is covered, rely predominately on volunteer or combination firefighting forces. Communities with more than 20,000 people almost never can sustain a volunteer force for a lengthy period of time without strong management and leadership.