What Is A (1, 2, 3, 4, 5) Alarm Fire? Firefighter Answers

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One of the mysteries of the firefighter’s world is the fire alarm code. Many people come across it on cable TV shows or overhear a firefighter using it in real life but don’t know what is it and how does it work? What are firefighting alarm assignments?

A 1, 2, 3, 4, or 5 alarm fire refers to the number of resources (firefighters and apparatus) needed to contain and extinguish the fire, based on its size and severity. Each firefighting alarm assignment typically has 2-4 fire engines, 1-2 ladder trucks, 1 rescue/air unit, and 1 battalion chief, though this varies.

Alarm assignments can give you an idea of how serious an incident is being worked. Let’s take a closer look at how this system works.

Your # 1 priority is keeping your family safe. As a firefighter, I recommend everyone has updated smoke detectors that don’t require battery changes, like these ones from Kidde, a fire extinguisher, like this one from Amerex, and a fire escape ladder if you have bedrooms above the first floor, I recommend this one from Hausse.

Also read: What’s the Difference Between a Fire Engine and a Fire Truck?

1,2,3,4,5 Alarm Fires: Fire Alarm Assignments Explained

what is a 1, 2, 3, 4, 5 alarm fire

The fire service has to deal with fires from the smallest to the biggest and it’s important to be able to communicate the extent of the emergency and how much resources must be allocated to fighting a fire.

If someone calls in a wastepaper basket fire in their garage, the fire service will send out a fire engine and firefighters to deal with it if necessary, but they don’t want to send the same level of resources as they might for a burning gas station or high-rise apartment block. 

That’s not because they don’t take small fires seriously, they do, but with limited resources on hand, a fire service has to prioritize fires based on what they need to extinguish them. 

This is why the firefighting alarm assignments exist.

If you watch TV shows about the fire service (even the fictional ones), you’ve probably heard somebody say “It’s a five-alarm fire” or something similar but what, exactly, does that mean?

The alarm assignment sent to a fire is based on the number of personnel that is needed to handle it.

Also read: How Fast Does Fire Spread? (House Fire, Wildfire)

1 Alarm Fire

As you might expect a one-alarm fire is the “least serious” fire, but don’t think that means that the fire department will be phoning in their response if you’re caught in such a fire. It could still be a well-involved house fire and only require 1 alarm.

In fact, typically, they will send a pair of fire engines, a rescue unit, a ladder truck, and a battalion chief to manage the scene!

Fighting fires is all about making sure you have the right resources on hand immediately and because a one-alarm fire can spread and quickly become “more alarms”, it’s better to have extra capacity to fight the fire on hand than it is to run out of capacity when the scene calls for it.

The first unit on the scene of a one-alarm fire is also tasked with evaluating the alarm level of the fire. If they think that the severity has been underestimated? They can upgrade the alarm and call for more resources.

Also read: How Much Do Fire Trucks Cost? Apparatus Types and Prices

2 Alarm Fire

As you’d expect, a two-alarm fire immediately requires more fire engines, fire trucks, and firefighters than a one alarm call, and these resources are swiftly allocated the moment that the call goes in.

Usually, each alarm after the first will get another 2 engines, a truck (aerial), and another chief officer.

However, they also require two more specialist pieces of equipment in most fire services – a support vehicle and a hazardous materials vehicle. Again, this will really vary by department.

This ensures that additional equipment that is needed for tackling more severe fires is on hand – such as additional oxygen tanks for personal breathing apparatus. 

A two-alarm fire may not sound like much, but it may see up to thirteen vehicles deployed from the fire department to assist in extinguishing the blaze! 

Again, the firefighters on the scene may call in and request that a two-alarm fire be upgraded in severity both when first attending the scene and later on if complications develop. 

A two-alarm fire could be a fire at a 2 story apartment complex, with multiple units involved or it could be a small house fire that requires rescuing people trapped inside.
The alarm number does not directly correlate with the size of the building or the amount of fire involved. It is about how many people and tools are needed to handle the entire incident.

Here is an example of a 2 alarm fire:

Also read: How Long Does It Take To Put Out a House Fire?

3 Three Alarm Fire

Three alarms, as you can probably guess, means tripling the resources that are going to be deployed when compared to a single alarm fire. 

This means an additional alarm assignment. It may be a larger, more complicated incident, or it may just be a fire that takes longer to put out.

When it burns longer, you need more people to rotate out and make sure firefighters are able to safely do their job.

At this point, the fire service knows that they will need to ensure that the firefighters on duty will need support to keep their energy up and can deploy a vehicle that is stocked with both snacks and electrolyte solutions (this is better than water as it replaces lost salts that are sweated out when doing intense physical labor like firefighting).

They also know that it’s unlikely that a blaze that burns for several hours in the modern world is going to go undetected by the keen eyes of the media and they may also send out a special vehicle for media relations so that the firefighters can continue to work without being interrupted by the media and so that the media can get the latest information they need. 

Here is a 3 alarm fire:

Also read: How Much Does Firefighter Gear Weigh?

4 Alarm Fire

Once you hit four alarms, you’re talking about a genuine catastrophe taking place.

These are not common occurrences, in fact, you might only see 2 or 3 of these a year for any given fire department, maybe less. This means a firefighter might only be called out on one (or even none) each year but, of course, eventually, they will have to face a four-alarm fire.

Given the scale of this kind of blaze, you may now see up to 21 fire fighting vehicles deployed to fight the fire and there could be up to 6 battalion chiefs on the ground to coordinate all the activity. 

Big fires are complex to handle, and each firefighter needs clear instructions to follow and the necessary amount of support to do their job effectively. 

This one is a 4 alarm fire:

Also read: How Many Firefighters Are Needed to Fight a Fire?

5 Alarm Fire

For a single fire department, this simply means that the fire is so huge that all available hands are likely to be needed to put it out.

Fires of this nature are not everyday occurrences some firefighters might go through their entire careers without ever tackling one and no firefighter will have fought more than a handful. 

The biggest structure fire that I have personally been on, in 10 years as a firefighter, was 4 alarms.

By now, you’re going to see more than 20 fire engine companies deployed to get the water flowing, a rescue company will be required too to ensure that people can be freed as necessary, you’ll see up to a dozen ladder companies, as well as a squad company. 

And that won’t be all, there may be, air support, ambulance services, hazardous materials vehicles, media teams, and snack trucks too. 

The chain of command will be out in force too and there will be a division chief, a deputy chief, and a chief of operations on hand.\

And here is a 5 alarm fire:

Also read: Black Smoke: What Does It Mean And What Causes It?

Is There Any Such Thing As A More Than Five Alarm Fire?

Yes, fire alarm assignments can go above five alarms, as high as needed. They may be required to call for resources from neighboring departments to handle the number of personnel and apparatus that is needed.

The highest alarm fire in history was a 16-alarm fire (some sources say 20 alarms) in Brooklyn, New York in 1995. You can see more about it here:

Can The Fire Alarm Number Go Down On A Fire?

Yes, just like a fire alarm number can increase if things get worse, a fire alarm number can decrease if things get better.

If the Incident Commander (IC) on the scene believes that the severity of the fire has been over-reported in the first instance. Always better to send more resources and send them back if you don’t need them when time can make a huge difference.

Sources: 1 2 3 4 5 6 7 8 9 10

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