Sun Oct 11, 2015 9:54 pm
The jurisdiction (city council, fire district, etc.) that oversees the fire dept., has the say over whether the siren is activated for fire, rescue, etc. calls. I have also seen it spelled out in particular ordinances, where the fire chief may be responsible over the siren system.
Anyway, the responsible party that oversees the siren system, determines when (day, night, etc.) and for what calls (fire, rescue, etc.) the siren sounds for. Each community (city, township, fire district, etc.) has its own policy.
Basically, pagers may not be effective in some communities, so sirens are also sounded. If a siren paging tower is far away, hills or tall building(s) are impeding, etc. may result in a lack of pager coverage. In some cases, outdoor warning sirens are also used to supplement or backup a paging system.
Contact your local fire chief and inquire for what and when the sirens are used. That will clarify why (or a lack of) sirens are activated.