The Basics of the Incident Command System

APCO Institute Curriculum Handout
Written by Kathy Schatel, APCO Institute EMD Services Coordinator


Incident Command is a term that is found in almost every public safety situation, referring to policies and procedures that establish the command structure for incidents. Communications is a part of the Incident Command System (ICS) and you must be familiar with your role in the incident and how it relates to unit response.

The ICS was developed to prescribe a common terminology and method of operating at emergency incidents. Standardization enables agencies that never or rarely work together to instantly recognize terminology and actions in an emergency with a minimum of confusion.

To understand ICS is to understand the building blocks of a command structure that can be built as big as needed to manage and mitigate the given emergency. ICS is used in fires, natural disasters, hazardous material incidents, and mass or multiple casualty incidents (MCI). The Incident Command System is a sophisticated resource management tool that can expand or control to fit the size of any emergency.

Functional Callsigns

Functional callsigns are a major ingredient of ICS. In pre-ICS days, units would arrive at an incident and use their normal callsigns, such as Engine 2, Rescue 5, or Battalion 4. This is fine for a small incident, but in large multi-jurisdictional incidents it could cause some confusion. There could be two Engine 3's or two Battalion 4's on the same scene. Confusion could also be caused by not knowing to whom you were speaking. This is particularly true druing prolonged incidents where there were changes in personnel doing specific jobs. By using a functional callsign these problems are reduced or eliminated. A functional command callsign is named after the job the person does, rather than who they are. As an example, the person in charge is the incident commander or IC, regardless of who holds that job during an incident. Other common functional callsigns used in ICS include: Staging Area, Medical, Operations, Logistics, and Tactical sub units such as strike teams, task forces, divisions, and sectors. In structural fires some of these titles can also be location related such as: roof, interior, and basement.

Command Span

ICS was build to a command span principle designed to make the most effective use of leadership and control. A tactical leader can effectively manage up to five resources. Thus in ICS the magic number is five resources. As an example, a strike team is five of the same type of apparatus under the command of one officer called a strike team leader. Five strike teams operate under one sector officer and five sectors are under the control of a division officer. Thus 125 fire apparatus would be operating under the command of the division officer, but that officer would only need to give orders to his five sector chiefs. On a major wildland fire there can be several hundred apparatus operating at any one time, along with ground crews and aircraft in a complex coordinated effort to contain the fire.

Below are important basic ICS terms that every communicator should understand. They are listed in logical order, as opposed to alphabetical.

Resource
Any equipment or personnel needed, requested or used to manage or mitigate the emergency.

Allocated Resource
A resource dispatched to an incident but not yet checked in at the incident.

Available Resource
Resources checked in at an incident and ready for an assignment.

Base
Location where primary logistical functions are coordinated and administered, NOT the command post: supports the command post by managing many essential tasks. Bases are frequently used in major wildland fires; large incidents may have multiple bases. Bases frequently have a location name attached to them as an identifier, i.e. "Camino Base," "Main Street Base," etc.

Staging Area
The location resources report to during an incident: May be separate locations or part of a base; urban staging is frequently set up on a street within a few blocks of the fire; units wait at the staging area until assigned a task; staging areas are an active part of communications during major incidents.

Command Post
Location of the person(s) with primary command responsibility. The command post may be located at the base or elsewhere; Usually well marked.

Incident Commander
Person who is charged with the overall strategic command of an incident; Ultimate resource manager for an emergency; Person filling the Incident Commander position may change several times during an incident.

Section
An organizational level that has responsibility for primary segments of an incident. Examples of sections include Operations, Planning, Logistics, and Administration/Finance.

Unit
Organizational element providing a specific support function working under the control of a section. Examples include: Weather Forecasting Unit, Time Unit, Medical Unit, and Communications Unit.

Branch
An organizational level having functional or geographic responsibility for major segments of the operation. Examples could include: Air Branch or Support Branch.

Division
An organizational element that is responsible for the tactical operations within a defined location. Examples can be identified by letters, such as Division A, or by geographical location such as North Stairwell, or by Roof Division.

Sector
Two options: 1) Used as a specific location within a division, i.e. a large building has a roof division, and is then broken up into "logical" sectors; normally numbered, i.e. Roof Sector 2.
2) Describes a division or a group.

Group
Organizational element that provides a primary job within an incident; May include Fire Attack, Primary Search, Ventilation, etc.; In large incidents such as high-rise fires groups may be further identified by location (14th Floor Fire Attack), or with an alpha-numeric identifier (Fire Attack 1,
Fire Attack B).

Crew
Lowest level of organizational element; Can be a permanent unit, such as an engine company which arrived at the fire, or one made up to do a specific task; Will ALWAYS have a designated leader, and in most cases will have the normal command span of five persons. (Exceptions may apply.)

Strike Team
Five of the same type of resource under the command to a strike team leader; Varied in their make-up; Is common to have bulldozer strike teams, ambulance strike teams or engine strike teams; Generally have numerical designator (Strike Team 4511).

Task Force
Up to five dissimilar resources grouped together for a specific task. Example: three hand crews and two engines grouped together under the command of an officer. Identifiers such as Task Force 27.

Agency
A specific entity involved in the management or mitigation of the emergency, i.e. police, fire, public works, EMS or others.

Assisting Agency
An agency with resources directly committed to the management and mitigation of the emergency. Example: an Urban Search and Rescue (USAR) dispatched by FEMA, county animal control, etc.

Cooperating Agency
An agency providing support or assistance other than active management or mitigation role. Examples include the Red Cross, Salvation Army, Civil Air Patrol, Army Corps of Engineers. Law enforcement resources fall under either category depending on their actual job function for this emergency.

Agency Representative
The individual assigned from an assisting or cooperating agency that has been empowered to act as the decision-making authority for that agency during the emergency. When multiple agencies and jurisdictions are involved these representatives are generally grouped as "Unified Command" and provide staff and liaison functions for the IC and his executive staff.

Incident Action Plan
Plan developed by the incident commander; outlines strategic goals for incident management and mitigation, and related tactical objectives to meet the goals. All incidents require an action plan, written or verbal. Larger incidents, especially thost that involve major disasters or prolonged operations lasting longer than 12 hours, require more complex written plans. Generally in these large incidents, the staff group responsible for a given portion of the support plan writes that portion. The IC is then free to concentrate on the actual management of the incident. Examples include the medical plan, the food service plan, and the communications plan.

ICS appears very complicated. While there are many branches, sections, groups and other units working together on the incident, ICS actually serves as a way of getting everyone to cooperate. Remember that the ICS can be expanded or contracted as needed. Communications is greatly simplified by the use of ICS. Everyone knows whom they report to. The radio traffic to the IC is limited to necessary members of the command staff only. Larger incidents can occupy multiple frequencies to further isolate key staff groups and allow for a more focused approach to incident management.