Denver Fire Dept. Terminology 

Based in part on Recruit Manual

A-CAR: Arson investigation vehicle. Radio call sign: "Arson", i.e. Arson 7.

AIR LIGHT: Mobile air cascade and flood light unit. Assigned to Fire Station No. 8.

ALARM: Notification to respond to an emergency; may be by fire alarm box, telephone, in person, by radio, or other means.


APPARATUS: Any fire department vehicle having a shop number, and equipped with firefighting equipment.

BIG HAMMER: Watch your language, guests are in quarters.

BIG LINE: 2½ inch hose line or greater.

BIG STICK: Aerial ladder.

BUS: Ambulance.

CHAIN OF COMMAND: Unbroken line of authority extending from the fire chief through a single subordinate at each level of command, down to the level of execution and return.

CHIEF OF THE DEPARTMENT: The chief executive officer of the department, with full authority and responsibility for management of all department activities.

CLASS 1, CLASS 2 and DFD BOX: Classification of automatic fire alarm systems. Class 1, commercial; Class 2, residential; DFD Box, institutional, i.e. school building.

CODE 9: Medical response requiring ambulance only; non-emergency response. (Can be upgraded to Code 10) 

CODE 10: Medical response requiring Denver Paramedics and Denver Fire Department; emergency response.  (Can be downgraded to Code 9)

COMMAND OFFICER: Officer of the Classified Service holding the rank of Chief of the Fire Department, Deputy Chief, Division Chief, Assistant Chief, Captain, Master Mechanic, Superintendent of Fire Alarm, Assistant Superintendent of Fire Alarm, and Assistant Master Mechanic.

COMPANY OFFICER: An officer assigned by the Department Chief to command a company unit on a shift or platoon.

DECON UNIT: Responds with Hamer 1 on full hazardous materials assignments. Assigned to Fire Station No. 9 and cross-staffed by 9's personnel.

DISTRICT: One of six geographical sections of the city in which a number of fire stations are located under the jurisdiction of a District Chief.

DISTRICT CHIEF: An officer with the rank of Assistant Chief assigned by the Chief of the Department to command a shift or platoon within a district.

DROP: Meaning to assign to a call, i.e. "We will drop you on the call," the fire dispatcher said

EVOLUTION: A specific action used to standardize firefighting and rescue methods.

GREATER ALARM: A two, three, or four alarm fire, or other major emergency to which additional companies are requested and dispatched to aid in the prompt control of the emergency.

GROUP: Structural fire assignment, i.e. three engine companies, three truck companies, two district chiefs, Rescue 1, Hamer 1. Similar to "box assignment" in other U.S. cities.

HAMER 1: This is the abbreviation the Denver Fire Department uses for its hazardous materials response unit. Pronounced "Hammer." Radio call sign: "Hammer 1." Most other cities use the term "Hazmat." Assigned to Fire Station No. 6 in Auroria. Responds citywide on Hazmat incidents and structure fires. Also answers downtown EMS calls.

HAMER 3: Dump truck available for use on hazardous materials assignments.

HOLD ORDER: Fire companies requested to remain in quarters for assignments. 

"LT": Lieutenant.

MUD: Stop, Wait

NIGHT WATCH: Common term still used but, no longer recognized. The watch was between 2000 - 0730 hours. The watch person would sleep near the Watch Desk and would be responsible for Alarms and phone calls. The position of night watch is no longer utilized but, the responsibility of monitoring the radio’s can take effect if the vocal alarm is down. 

OFFICER: Any member promoted to rank of Lieutenant, or higher position of authority, in the classified service of the Fire Department. However, officers are still members of the Fire Department, but are classified as officers to differentiate their duties and responsibilities where practical.

OVERHAUL: The cleaning up period after a fire has been controlled, ensuring extinguishment of all spot fires.

PAIR: Engine company and ladder company assigned to same firehouse. 

PICK UP: Return to quarters. 

PLATOON: The total firefighting personnel on duty during a working period; also referred to as a shift.

QUARTERS: Any fire station or building where members are assigned for duty.

RED: Aircraft rescue and firefighting (ARFF) equipment assigned to Denver International Airport.

RED CHIEF: District chief at Denver International Airport.

RESCUE 1: Heavy rescue. Responds citywide on extrication jobs, technical rescues and structure fires. Assigned to Station No. 11.
RIT: Rapid Intervention Team.

SHIFT: The scheduled working period, the total firefighting personnel on duty during that period; also referred to as a Platoon. 

SQUAD: Disbanded emergency and manpower unit that operated citywide. Retired vehicle on display at fire museum. Somewhat  equivalent to current Rescue 1 and/or Hamer 1 in some duties performed.

STICK: Aerial ladder. 

SUPPORT DIVISIONS: Those divisions other than Operations Division responsible for day to day operations of the Fire Department, such as Fire Prevention, Technical Services, Administration, Safety and Training.


SUPPRESSION FORCES: Those members assigned to fire companies in fire districts and the airport .

TACTICAL ATTACK COMPANY: Disbanded. Unit organized in 1980s consisting of two-person mini-pumper and four-person tower ladder.

TOUR OF DUTY: The shift during which an individual member is on duty. 

UNIT: The group to which a firefighter is assigned, or the assigned number issued to all department vehicles.

VOCAL ALARM: Fire station alerting system. Simulcast on old VHF dispatch frequency of 154.070 Megahertz.

WATCH: The period of time a company member is assigned to perform the specialized duties at the Watch Desk in fire stations. This duty should not be construed to include "watch duty with restrictions," assigned to members outside their normal work schedule. 

WILCO: Will comply.