Fire Alarm Degrees: What You Should Know

When the fire department is notified of a fire they need to have some understanding of the scale of the problem they are dealing with.

This helps them to decide how fast they need to get to the scene and how many resources to send there.

They cannot send all of the resources to each fire as there could be multiple emergencies happening at the same time across their jurisdiction. 

That is why the fires are categorized into different degrees to represent the level of threat. Everyone in the fire department understands the difference between these degrees and how the fire department should respond to each one. 

If you want to know more about the fire alarm degrees, what they mean, and what response they trigger then keep reading. We have put together this useful guide to tell you everything that you need to know. 

Fire Alarm Degrees: What You Should Know

One Alarm Fire 

If there isn’t much information available about the fire then it will be categorized as a one alarm fire.

This means that two fire engines will be dispatched to the fire along with a rescue unit and a ladder truck to ensure that they can reach upper floors if needed.

A battalion chief will be on board one of the trucks to supervise at the scene. 

Once the crew arrive at the scene they can get a better idea of the scale of the fire and what is needed.

It is unlikely that they will send resources away unless it is clear that they are not required and there is a bigger emergency elsewhere.

If more help is needed they will update the status to a two alarm fire and the station will send more resources. 

Two Alarm Fire 

If the fire is categorized as or upgraded to a two alarm fire then this will double the resources sent to the scene.

A hazardous materials vehicle will also go to the scene which will allow the firefighters to deal with a bigger range of scenarios safely. There will also be a support vehicle at the scene with extra supplies of oxygen and other equipment. 

Once a fire has been classed as a two alarm, there could be up to 13 emergency vehicles present at the scene trying to tackle the blaze and rescue people from the building. 

Three Alarm Fire 

Anything beyond a two alarm fire is considered to be a very large, significant fire. These fires can easily spread and get out of control if they are not dealt with properly, so resources to this fire will be prioritized.

More units will be sent to the scene, along with firefighters not necessarily attached to a truck or vehicle as they can provide extra help.

It is likely that the firefighters could be working on this fire for many hours, so sometimes a truck will be sent to the scene with drinks and snacks so that the firefighters can keep their energy up. 

Once a fire has reached three alarm status, it is very likely that the press will arrive at the scene and begin reporting on the developments.

The fire officer or chief in charge of the scene will need to set up a perimeter to keep the public away from the danger and to give the fire department enough space to do their job without civilians getting in the way. 

fire alarm degrees

Four Alarm Fire

A four alarm fire is considered to be a catastrophic fire. They don’t happen very often - perhaps a few times a year in large cities and less in smaller towns and counties.

These fires cause significant property damage and are also likely to cause serious injuries or even to take lives.

Fires of this level may require up to 21 different vehicles and units and 6 battalion chiefs to supervise and make decisions on how to tackle the blaze. Firefighters who are not on shift may be called in to help out. 

Five Alarm Fire 

A five alarm fire is as serious as it gets. If a five alarm fire is called in then at least 20 fire engines will be sent to the scene immediately, 10 or more ladder companies, and at least one squad company and one rescue company.

There will also be a range of specialized units such as a hazardous materials vehicle, a supply truck, and a snacks truck. Air support might even be required. 

A perimeter will be set up and it is likely that nearby buildings will be evacuated in case the fire spreads. The amount of smoke and ash in the air will be a danger to bystanders and people in the surrounding buildings.

As well as the 6 battalion chiefs on the scene, the division chief will show up at the fire along with the deputy chief and chief of operations. 

Five alarm fires pose a serious threat to life so it is all hands on deck. As many firefighters as possible will be fighting the blaze, including people not on shift and maybe even firefighters from other jurisdictions. 

Are Fire Alarm Degrees Universal?

Fire alarm degrees are used across the United States to indicate the severity of the fire.

With a fire, every second counts, so using a clear system saves time when it comes to allocating resources and knowing how to respond to the threat. 

However, the exact breakdown of the degrees may differ between states and fire departments.

They broadly mean the same thing, but different fire departments have different amounts of equipment and resources so they may need to split their units differently in order to cover all risks across the jurisdiction.

Some states will be affected by different kinds of fires depending on climate and culture, so the fire departments will tailor their fire alarm degrees to suit their individual needs. 


Fire alarm degrees are extremely important when it comes to dispatching resources to the scene of a fire.

Using the right degree will help to save lives and ensure that the firefighters have the best chance of stopping the blaze.