An Effective Response Force (ERF) is defined by NFPA as the minimum number of firefighters and equipment that must reach a specific emergency incident location within a maximum prescribed travel (driving) time. The maximum prescribed travel time is an indicator of resource deployment efficiency. The response time is calculated at the 90th percentile to eliminate outliers.
Total response time is composed of the following time segments:
Alarm Transfer: The interval from receipt of an emergency alarm at the public service answering point (PSAP) until the alarm is first received at the fire department communication center.
Alarm Answering: The interval that begins when the alarm is received at the fire communication center and ends when the alarm is acknowledged at the fire communication center.
Alarm Processing: The interval from when the alarm is acknowledged at fire communication center until response information begins to be transmitted via voice or electronic means to the emergency-response facilities and emergency-response units.
Turnout Time: The interval from when the emergency response facilities notification process begins by either an audible alarm or visual annunciation at the beginning point of travel time.
Travel time: The interval that begins when a unit is en route to the emergency incident and ends when the unit arrives at the scene.
Initiating Action/Intervention time: The interval from when a unit arrives on the scene to the initiation of emergency mitigation.