The old adage goes that if you play with fire you are going to get burned. While not written purely for the advice of fire pit enthusiasts there is no denying the old words ring true.
Yes, fire pits can be great focal points for a fun evening of socializing and merry-making, but the key component of fire should not be underestimated. As fire pits have increased in popularity in recent years, so too have the incidences of accidental burns and injuries when using them.
The incredibly hot heat achieved in some models and the material used in construction can result in incidences of a fire pit exploding. So, whether you have already had a near miss or you are just looking to learn from the mistakes of others, read on to find out what can occur to result in your fire pit going boom!
Fire pits are great additions to your outdoor space, but the risk of explosion comes with flames. Whilst explosions are rare they can happen. The most common culprits of fire pit explosions are a lack of ventilation, the wrong fuel, the wrong fire pit material, or a gas leak
Why do Fire Pits Explode?
There are a number of potential reasons that your fire pit may explode. Most of it comes down to some basic scientific principles around heat and expansion. Read on below where we have tried to simplify the main reasons for fire pit explosions:
Trapped Water
Fire pits are made for outdoor use and as such can be exposed to water in the form of rainfall and atmospheric moisture. Depending on the material used in your fire pit, water or moisture can soak in. If a fire pit rises in heat rapidly that can cause the moisture to quickly transform which can quickly, plainly blow your pit apart as it tries to make a speedy exit.
Cracks/Damage
Again, depending on what your fire pit is made of it may develop cracks or fissures over time. This is why it is important to inspect your fire pit prior to each use. There will be hot air and gas within the base of your fire pit. If cracks are there the heat and gas can push through these with enough force to blow them even wider.
Lack of Ventilation
Poorly constructed fire pits can lack enough ventilation to let the hot gases escape, if this continues unchecked it’s a recipe for a massive boom and potential injury to anyone in the vicinity.
Piling on Too Much Fuel
There can be a temptation to overfill your fire pit for maximum warmth, this should be avoided. The more fuel, the hotter the heat. The hotter the heat the more gases that occur as part of combustion exist. There can be a tipping point where these can become flammable and create an explosion.
Burning the Wrong Fuel in your Pit
If you burn fuel that gets too hot or isn’t specifically intended for your type of fire pit this is a surefire way to head toward an explosion. Equally burning fuel not designed for fire pits is also a no-no. Aerosol cans will pop, plastics give up toxic fumes and flammable liquids can quickly ignite.
Which Fire Pit is Most Likely to Explode?
By far the biggest culprit of fire pit explosions is the DIY stone-built affairs. While it may seem a simple enough affair to dig a basin and stack some rocks or stone, the type of material you use for the side needs to be carefully considered. Strictly speaking, if you cannot confidently identify the type of rock/stone you should not use it.
As a rule of thumb, any porous rocks such as those listed below are strongly advised to be avoided. Unless the fire pit can be kept completely dry, these rocks can absorb even the smallest particles of moisture that will expand under heat.
- Pumice stone
- Mixed gravel
- River rock
- Sandstone
- Rocks that appear very smooth (as they have lightly been smooth by water erosion)
What Does a Fire Pit Explosion Look Like?
This short clip shows how pouring on a flammable accelerant can make an unpredictable explosion when lit:
This clip shows the shocking explosion that can occur with a gas leak:
What Stone can I use in my Fire Pit that is Unlikely to Explode?
Some sensible alternatives that are much less likely to explode include:
- Slate
- Marble
- Granite
- Some types of concrete
Now, if you are looking for stones to line the base and edge of your firepit, these need to contend with the highest of heats. The best choice for this is lava rock or fire glass.
Lava rock can handle molten lava temperatures. However, it needs to be ensured that they are bone dry! You can do this by “curing” them. A process of putting them in your fire in small numbers with a lid over the top. Over a reasonable flame, you will hear some popping as the water escapes. The covering stops the rocks from flying out and hitting anyone. Doing this in batches ensures no large-scale explosions
Fire glass is another option. However, this has to be specialty-produced fire glass. This will have been specially prepared to remove sharp edges to prevent injury. Using standard glass could be dangerous as often it can contain coatings or additional materials that can produce toxic fumes and also potentially explode.
Which Fire Pit is Less Likely to Explode?
Although the idea of a gas line or a propane canister near open flames sounds like a surefire route to an explosion, surprisingly a professionally fitted and well-maintained gas or propane fire pit is often less prone to explosion than a wood-fired alternative.
The main bonus is that a gas-fired fire pit doesn’t produce sparks, smoke, or embers and there is the option to kill the gas or propane supply instantly by closing off a valve.
This is of course dependent on safe use as a gas or propane fire pit does produce a fair bit of carbon monoxide. If you’re irresponsibly in a confined space with minimal ventilation this can cause an explosion. The second culprit of a gas fire pit explosion would be a gas leak however as both gas and propane have a scent this would be apparent fairly quickly, likely before an explosion could occur.
How to Prevent a Fire Pit from Exploding
So, what can you do to prevent your fire pit from exploding? We have a basic checklist below
- Keep your fire pit covered when not in use to prevent unnecessary moisture
- Visually inspect it before each use looking for any cracking or signs of moisture
- If you have built it yourself ensure you have used a non-porous rock/stone
- Choose your fuel wisely and don’t over stack
- Remember the need for ventilation, raise your fuel with a grate if necessary to help airflow.
So with just a few checks and some sensible tips, you should be free to enjoy many warm, safe, and cozy nights gathered around your very own outdoor fire pit.