What Is A Code 4? Firefighter Radio Codes

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If you’ve ever listened to firefighters, even if just on the TV, you’ll know that they seem to have their own special language, including a set of radio codes that lets them communicate important information in a standardized fashion. But what are these codes and what do they mean? Well, let us walk you through it. 

Code 4 means that no further assistance is needed and is used as a radio code in emergency services. This communicated to other responding resources (fire, police, ambulance) to let them know that they can cancel their response.

The fire service has moved away from many of the radio code language that was previously used, but there are certainly some codes that are commonly used. We will take a look at the radio codes that are used, what they mean and how they can vary by location. Take a look.

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Also read: Does 911 Cost Money? The Price of Emergency Calls

Are Emergency Service Codes Standardized?

firefighter radio codes

In the United States, the highest level of emergency service codes are standardized.

That is Codes 1 through 4 which are used, specifically, to describe the manner of response that will be used by an emergency vehicle when it responds to an emergency call.

Thus, it dictates how urgent the matter is and whether or not things like lights and sirens should be used when responding to a call. These are not the same, as we shall soon see, as the Priority Terms (which are ranked from 1 to 5) commonly used by Paramedics and Emergency Medical Services and it can be easy to become confused between the two. 

What Is Code 1?

A Code 1 response is a “cold response” this means that it is the lowest priority type of call, you would expect the vehicle to be heading to the response with no light or sirens because there is no reason to employ them. 

This does not mean, however, that the call is pointless or that the incident will be abandoned in favor of something more pressing, it just means that there is no need to go in as though a high-speed, high-intensity response was required. 

In essence this is used when there is a “routine or scheduled transportation of non-emergency patients”. 

What Is Code 2?

Code 2 is a slightly different form of “cold response” which is employed when a “non-life-threatening emergency requiring immediate response without the use of red lights or siren” takes place.

In many cases, a Code 3 call might be downgraded to Code 2 when a first responder arrives on the scene and determines that the issue is not as urgent as originally thought.

Again, this doesn’t mean that this call will be treated as unimportant, just that there is no need for the emergency services to rush to the scene and risk their safety and/or that of the general public. 

What Is Code 3?

A Code 3 is a “hot response”, you would certainly expect any vehicle responding to a code 3 call to have their lights and siren on. 

This is a call where there is deemed that there is a life-threatening emergency and it is important that the medical response team get to the scene as fast as possible, in order to effectively respond to the call.

It is possible for a Code 2 call to be escalated to a Code 3 call if the situation requires it.

What Does Code 4 Mean?

If there are enough responders on the scene and there is no need for further vehicles to be called, then a Code 4 might be given. This is an instruction to discontinue the call.

However, we would note that when we examined the radio code policies of different departments in the United States – not all of them allowed for the use of Code 4 and only employed Codes 1 to 3. 

Thus, it would be important for a firefighter to be fully familiar with their local policy before calling a Code 4, because of the possible risks of misleading or confusing their colleagues. 

What Are Priority Terms?

firefighter radio

These are a set of non-universal terms which are employed by some medical service agencies and paramedic teams, as such, there may be some carry over into the firefighting world, as many firefighters are also fully qualified paramedics.

They should not be confused with the radio codes above but are as follows:

Priority 1 – DOA (Dead on Arrival) Trauma/CPR: This is to signify that the victim is deceased

Priority 2 – Emergency: Fairly straightforward, an explanation to the hospital that there will be a need for urgent support when the victim arrives

Priority 3 – Non-Emergency: Sometimes, paramedics respond to calls that do not result in emergency treatment, but where the patient will still need to be transported to a hospital

Priority 4 – Situation Under Control: A signal that no further action will be needed for the patient

Priority 5 – Mass-Casualty Incident: Yes, while you may have expected this to be the least serious priority, it is actually very serious and warns the hospital dispatch that there may be many patients on the way and potentially many requiring emergency treatment 

The National Incident Management System (NIMS) And The Shift To Plain Language

The United States has long been examining the practical value of radio codes and there is a case for the use of plain language in radio communication in the modern era. 

Codes were useful when high-quality radio performance was a rarity but today, this is no longer such an issue and even smartphones are capable of delivering high-quality “push to talk” radio signals. 

They say that, “”it is required that plain language be used for multi-agency, multi-jurisdiction and multi-discipline events, such as major disasters and exercises”.

That means that when more than one emergency service is involved – plain language is needed and, in fact, back in 2006, they ensured that any federal grants given for these operations required the use of plain language too.

They have also recommended that individual agencies adopt plain language. Given that you’re reading this, today, you can see that this recommendation has not, yet, at least, been taken up universally. 

This shift is meant to replace both the codes above and 10-codes used in inter-agency use but, interestingly, it does not prohibit the use of 10-codes in single agency use, which may explain why these codes are the best-known of them all. 

What Are 10-Codes?

Ten-codes aren’t 10-codes at all, they’re “ten signals” though almost no-one calls them that.

They are considered to be “brevity” phrases that allow law enforcement and other services to communicate effectively with each other.

However, they lack standardization of any kind and may vary from department to department. This makes 10-codes among the most confusing codes in use in the USA and many feel that they should be replaced with plain language and in 2012, ACPO international, mandated a transfer to plain speech over the radio. 

This hasn’t been entirely successful, but many states have now phased out 10-codes and they are not as common in use as they once were. 

Though they can vary, this video covers many of the common 10 codes used:

What Is A 10-55?

A 10-55 is a great example as to why 10-codes are confusing.

In my agency and the surrounding areas, a 10-55 is used to described someone who had died and is past the point of being savable. Also referred to as a “Coroner’s Case”.

However, in many areas, they say that a 10-55 refers to an intoxicated driver

There’s probably no better reason for their replacement with plain English than that, right? 


We hope that our guide to “What is a code 4? Firefighter radio codes” has been helpful and that you now have a better grasp of what the codes used for firefighting and emergency responses in the United States mean. However, be aware that these are not always consistently used and there may even be times when they are best replaced by the use of “plain language” or “plain English”. 

So, if you intend to work as a firefighter, it’s always best to check exactly what coding systems are in place in your fire department before you start to put your knowledge into practice, the odds are that you’re good to go but if you don’t check and you get something wrong, it might land you in hot water. 

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