Dorky Firefighter Fire Extinguisher





Introduction: Dorky Firefighter Fire Extinguisher

About: College student, firefighter/EMT, avid tinkerer, always loved working with my hands. Interested in a lot of things, so my tinkering tends to make dorky appearances.

I'm a new volunteer at the local fire house and I learned an interesting way to put out a fire. With summer rolling in at full force, so do rates of easily preventable fires taking charge. In this 'ible, you'll learn how to have an affordably fire-safe summer.

Background/General Knowledge

There are five classes of fire that are controlled by different types of fire extinguishers. For now, what matters are Class A, B, and C fire extinguishers, which control combustible dry materials (such as paper, wood, and cloth), flammable liquids (such as gasoline, oil, and paint), and electrical fires respectively. The ingredient in common? Sodium bicarbonate, commonly known as baking soda.

Chemistry Saves Lives

The chemical reaction stands to reason:

When heated above 50 C, sodium bicarbonate is decomposed to sodium carbonate, water, and CO2.

2 NaHCO3 → Na2CO3 + H2O + CO2

At 850 C, the carbonate is converted to an oxide.

Na2CO3 → Na2O + CO2

The long and the short of it, the heat from the fire is used to drive the reaction that yields CO2, thereby replacing oxygen, which supports combustion.


The original idea trademarked at this fire company by a seasoned veteran was that a plastic bag full of baking soda could be dropped down a chimney to put out a fire, known as a "chimney bomb". Fire melts the bag, baking soda gets released, fire is extinguished.

In reality, this bagged baking soda method is in no way ideal. If by chance you are caught in a situation where there is a fire and have a box of baking soda but not a certified fire extinguisher, it would be helpful. Helpful, but again, in no way ideal.

The main purpose of this Instructable is to give a quick and simple chemistry lesson. The safest way to proceed with this chemistry experiment is to attempt extinguishing a candle flame.


While this DIY fire extinguisher is as workable as a Class A, B, and C fire extinguisher, it should not replace a certified fire extinguisher. Above all, this should supplement your fire extinguisher in the event of a fire.

In the event of a fire, call 911.

Do not test the effectiveness of this Instructable at home.

Step 1: Materials

All you need for this DIY fire extinguisher is:

-A plastic bag (preferably not ziploc)

-A box of baking soda

-Optional cutting board to contain the mess

Step 2: Filling

Simply fill your bag with baking soda. I'd recommend using the whole box. You never know, you might need the whole thing. For bags this thin with such a capacity, I wouldn't recommend using more than a box. The bag could break open unexpectedly and leave you with a mess and without fire protection.

Step 3: Tie Off

An overhand knot will do. If you see yourself wanting to add or remove baking soda in the future, you might want to go with a figure-eight knot.

Step 4: Ready for Use

To take my own advice from the introduction, I won't document proper technique. Just know that this DIY fire extinguisher is usable for Class A, B, and C fires. In other words, dry combustible materials, electrical fires, and flammable liquids.

In the event of a fire, toss the bag into the fire source. Do not open the bag and sprinkle its contents on the fire. The point of the bag is a last resort to keep you safe. Getting close to the fire puts you in danger. Using the DIY fire extinguisher should buy you enough time to call 911 for assistance before the fire gets out of control.

This DIY fire extinguisher should not replace a certified fire extinguisher, only supplement.

This DIY fire extinguisher will not put out a large fire. If large fire danger is high, use a certified fire extinguisher.

In the event of a fire, call 911.

Do not test the effectiveness of this Instructable at home.


Kitchen fires are best extinguished with wet chemical extinguishers, so a Class K fire extinguisher would be a good investment unless you have an electric stove. Same applies to flammable metals, which are controlled using Class D fire extinguishers.



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    15 Discussions

    I am in no way any expert on fire safety or remotely certified to give this advice, but here are my two cents. This will not put out a fire, nor was it meant to. From what i can infer this has two jobs, a chemistry project, and a last resort. If there is a small fire you could toss this on there to slow it then immediately call 911 to let the professionals do their job. But you should still buy a fire extinguisher to be safe.

    5 replies

    Exactly right. A bag of baking soda this size will not put out a fire (except maybe a large candle flame). There are boldfaced disclaimers intended to keep people safe. My fire department uses multiple plastic grocery bags full of baking soda to put out a chimney fire and it's worked for decades. Baking soda (sodium bicarbonate) is the shared component of A, B, and C fire extinguishers, so it would put out a fire. Like you pointed out, this really is a chemistry lesson, so noting of a larger scale than this should be experimented with. Thanks for your concern!

    I think you have made an error an abc extinguisher does not contain baking soda all information shows that sodium bicarbonate extinguisher are for class b or c fires only

    You bring up a good point. Fire extinguisher classes do vary geographically. Depending on where you are from or what you are familiar with, your knowledge of the classes will differ. In the US, sodium bicarbonate is used for ABC fire extinguishers, as it works in all three classes. But if you wanted to specify for just Class A fires, foam or water would probably be a best bet.

    You said your new well I would suggest you check your notes again I have never herd of a baking soda extinguisher containing sodium bicarbonate for class a fires it is only for liquid and electrical fires abc powder contains mono-ammonium phosphate

    I guarantee you if you go to Ansul/First Alert/ sentry or Kidde/ Badger

    Or Amerex or any other U.S manf those are the major ones you will never find a class a rated sodium bicarbonate extinguisher if there is one I will eat my hat !!!! ( if threre is one please post it here so that I may see )

    No offense, but as I used to be a firefighter, this is extremely dangerous.
    I recommend that you remove this ible than give misinformation.

    1 reply

    It's tried and true and more of a fun chemistry lesson when in a controlled and supervised environment. There are disclaimers!

    Ok I get what everyone is saying & ALL are valid points in one way or another.

    For me, this is a perfect way to teach my daughter about different types of extinguishers & not pull my hair out. So on THAT note....Thank you bcrocker1 for putting this out for us (it's a chemistry project & I am sorely lacking those for her upcoming Senior yr).

    1 reply

    I work for a company that services fire extinguishers, so extinguishers are my job. This bag of baking powder WILL NOT put out a fire. The way a fire extinguisher works is by spraying a powder out of the nozzle in a stream. If you read the directions on an extinguisher it says to spray at the base of the fire in a side to side motion. This puts the powder over the entire area of the fire. What you have is a baggy of powder the size of a softball with no way to distribute it. This instructable is going to get someone killed. On another note, K-Class extinguishers are a liquid that will conduct electricity and I would not recommend them for anyone who has an electric stove.

    4 replies

    no what you just said will get someone killed cause theyight try to disperse random powders on a fire. as a fire eater. fire is also my job like yours and the auther is aswell as he is a firefighter. i myself have used this technique many times for small grease fires in the kitchen it does work and is a life saving technique for when the fire extinguisher guys come to your house or business amd just stick on a new tag saying its good when really its bad which has happened to me 3 times btw in the years i was a chef. so who should i believe the fire extinguisher tech who just said fire extinguisers function the same as when a fire eater breaths fire or the firefighter?

    I, unlike you guys, am not a fire expert of any sort. All I know is that baking soda does put out fire, like if there's a grease fire in the kitchen you should throw baking soda on it to out it out. Of course I'm not exactly sure why you would put it in a little bag like that instead of just dumping a ton of baking soda on the fire, I guess it's so you don't have to get close.

    Exactly right, just so you don't have to get close. Of course, a bag this size could probably only put out a candle flame. You'd need something like a grocery bag for a kitchen fire.

    Just a last resort and a fun chemistry lesson I learned from someone. Classically used as a "chimney bomb". I never suggested using it instead of a fire extinguisher. There are many disclaimers. Just for small fires. Thanks for your concern!