1.2: Communications & Radio Procedures (JPR 4.1.2)

1.2: Communications & Radio Procedures (JPR 4.1.2)

Public Safety Communications and Radio Systems

Emergency communications are the lifeline of the fire service. Clear, reliable, and standardized communication protocols are essential for coordinating operations, dispatching resources, and ensuring firefighter safety. Modern fire service communications rely on a centralized public safety communications center, standardized radio equipment, and precise radio protocols. The communications center, often called dispatch or a Public Safety Answering Point (PSAP), serves as the central hub. Telecommunicators, or dispatchers, receive emergency calls from the public, process the information, and dispatch the appropriate fire, EMS, or rescue units. They also monitor radio traffic, log incident milestones, and coordinate additional resources as requested by the Incident Commander.

Radio Systems: Simplex vs. Duplex

Fire department radio communications typically utilize two types of radio systems: simplex and duplex.

• Simplex System: A simplex radio system operates on a single frequency. In a simplex system, only one radio can transmit at a time; when a radio is transmitting, it cannot receive signals. Simplex channels are commonly used for short-range, line-of-sight communications on the fireground.
• Duplex System: A duplex radio system utilizes two separate frequencies: one to transmit and one to receive. Duplex systems require a repeater station, which is typically located on a high tower or building. The repeater receives the weak signal from a handheld radio on the transmit frequency and rebroadcasts it at a higher power on the receive frequency. This significantly extends the range of communications, allowing units to communicate across large cities or geographic obstacles. However, if a repeater fails or is out of range, firefighters can switch to "talk-around" channels, which are simplex channels that bypass the repeater for local communications.

Radio Communications Protocol: Plain Language

Historically, emergency responders used numeric ten-codes (e.g., "10-4" for message received or "10-20" for location) to communicate over the radio. However, because different agencies and jurisdictions had different definitions for these codes, they often led to confusion and communication failures during multi-agency responses. To address this, the National Incident Management System (NIMS) and NFPA standards mandate the use of plain language, also known as "clear-text." Plain language requires responders to speak in clear, everyday English, using standard terminology that is easily understood by all agencies. Best practices for radio operations include thinking about what to say before transmitting, holding the microphone one to two inches from the mouth or SCBA speaking diaphragm, speaking in a calm, controlled voice, and confirming receipt of all messages by repeating the core information.

Mayday Procedures and the LUNAR Protocol

A Mayday is a high-priority radio transmission reserved exclusively for firefighters who are lost, trapped, disoriented, injured, or in immediate, life-threatening danger. When a firefighter recognizes that they cannot safely escape an emergency situation, they must transmit a Mayday immediately. Delaying a Mayday is a common contributing factor in firefighter fatalities. As soon as a Mayday is declared, all other radio traffic on that channel must immediately cease, and the channel is reserved for the Mayday rescue operations. The Incident Commander will immediately deploy the Rapid Intervention Crew (RIC) to locate and rescue the downed firefighter.

To transmit a Mayday, the firefighter broadcasts "Mayday, Mayday, Mayday!" on the tactical radio channel. Once acknowledged by command or dispatch, the firefighter provides a LUNAR report. LUNAR is a standardized acronym designed to ensure that all critical information is communicated systematically:

• Location: The firefighter's current or last known position (e.g., "second floor, Charlie side bedroom").
• Unit: The firefighter's assigned company or apparatus (e.g., "Engine 2").
• Name: The firefighter's name (e.g., "Firefighter Davis").
• Assignment/Air: The task they were performing and their current air pressure in PSI (e.g., "ventilation, 1200 PSI remaining").
• Resources: What tools or assistance is needed for rescue (e.g., "pinned by ceiling joist, need wire cutters and a lifting tool").

Emergency Traffic and Evacuation Signals

In addition to Mayday transmissions, firefighters must understand "Emergency Traffic" procedures. Emergency Traffic is a priority transmission used to warn personnel of an immediate, severe hazard on the fireground, such as an impending structural collapse, rapid fire spread, or an order to evacuate the building. When the Incident Commander or safety officer orders an evacuation, they will broadcast "Evacuate the building" over the radio. Dispatch will transmit a unique, continuous evacuation tone. Additionally, on-scene apparatus will sound their air horns in a standardized pattern: three long blasts, each lasting approximately 10 seconds, with a brief pause between blasts. Upon hearing the evacuation signal, all interior crews must immediately abandon their tools, follow their hose line or guideline out of the building, and report to their company officer. A roll call, or Personnel Accountability Report (PAR), is conducted immediately after the evacuation is complete to verify that all firefighters have safely exited the building.