alarmer

One who alarms; one who sounds the alarm.

A multialarm fire of a specified number of alarms.

This three-alarmer brought out no fewer than seven steam pumpers, which are drawing water from a fire cistern...

“A two-alarmer,” someone commented. “Must be a nasty one.” We slurped our soda and ran for the trolley. “Fire's in Loray,” the motorman told us as he rang his bell.