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If there is one thing most of us don’t like about a warm fire, it’s smoke; it makes you cough, tear up, chases you around no matter where you sit, and your clothes smell of it for weeks—to say nothing about the potential impact on your health. Is it avoidable? Well, it can at least be reduced! And here we will tell you all about it. Here’s how to stop a fire pit from smoking so much.
More Reasons To Reduce Emissions
When wood burns, several of its components begin to heat up to the point of evaporation. Some of them are fairly innocuous: the water within will turn into vapor, and the carbon that makes up the wood will turn into dioxide as it comes into contact with the surrounding oxygen. There are, however, certain toxic elements that are released, such as formaldehyde, benzene and polyciclic aromatic hydrocarbons, or PAH. Due to its composition, smoke is more than just an inconvenience—exposure to it can also cause health issues, if these particles are inhaled. Some examples:
- Burning eyes.
- Heart attack.
- Irregular heartbeat.
- Worsening of asthma.
Children are at a heightened risk, among other reasons due to them breathing more oxygen per pound of weight than an adult; the elderly are another vulnerable group, as they are more likely to suffer of chronic respiratory or heart issues. Pregnant women are frequently advised to limit exposure, as their babies might be affected. Other risk factors include obesity and diabetes.
The health hazard smoke represents is taken so seriously, there is a type of restriction which all fire pit users should be familiar with; neglecting to do so might carry hefty fines.
A Primer on Burn Bans
The name is likely self explanatory: when this sort of prohibition is in effect, people in the area are not allowed to burn anything. This is done when concentrations of smoke in the air reach potentially harmful levels, which happens when there is a lot of burning done—such as fall and winter.
A burn ban is temporary, and it usually lasts just a few weeks. Anyone who wishes to start a fire (and this include the BBQ grill) should first verify if there is a burn ban in effect, and its rules.
How To Reduce Smoke
While there are several reasons why your fire is giving off excessive smoke, most of them have to do with the ‘fire triangle’, i.e. the three things a fire needs to start and to sustain itself.
An appropriate presence of all three elements will promote a healthy, efficient burn that won’t generate so much smoke. The following steps will cover more in depth how to achieve this balance.
Step 1: Mind What You Burn
While this may seem self-evident (and your fire pit’s manufacturer likely includes it in their literature), we might as well go over it. When starting and maintaining your fire, only wood should be used. That means steering clear of:
I know what you’re probably thinking: yes, some of that is used to start a fire, and that’s okay—what’s not okay is throwing large volumes into the fire pit. Large concentrations of seemingly harmless materials such as twigs, leaves and paper will cause much more smoke on their own. They may also interfere with the flow of oxygen, which will also increase emissions.
Step 2: Pick the Right Wood
Wait, what? We have to be choosy about wood too? Indeed! To begin with, some wood you may have lying around—and which you might be tempted to toss into the fire pit— has been treated in ways that make it optimal for its intended purpose, but would turn it into a toxic furnace if put to the flame. Construction wood, for example, comes with chemicals that prevent its decay when being out in the open while the structure in question is being built. Painted wood, well, is painted; nobody wants to inhale that. Other examples of wood types you should keep out of your fires are:
- Any pieces that are moldy or have vines.
- Green wood, or wood that has just been chopped. More on this a little further down.
A Matter of Species
It’s not enough for your wood to come directly from a tree; it is also important to know what tree that is.
In general, wood is separated into two types: hard, and soft. It does have to do with density, but the more fundamental rule is the class the tree belongs to. Trees that are angiosperm (shed leaves in the fall, reproduce via a flower or fruit) provide hardwood, as they take longer to grow—over a century, in some cases—, and the molecular structure is more complex. Trees classified as gymnosperm (evergreen, needle-like leaves, known to reproduce via nuts) are fully grown in roughly 40 years, and their internal structure is simpler, which is why they yield what is known as softwood.
Because of how rigid the differentiation is, it is not without its outliers. Balsa wood, for example, is technically a hardwood, even though it is so light and malleable it’s a favorite of the aircraft industry. But there’s no need to guess what’s best for your fire pit; here are a few tried and true choices:
- Ash. A common favorite, burns quite well.
- Beech. Another one with decent popularity.
- Oak. Remarkably dense, with a fairly slow burn; takes longer to ignite, and also to season (more on that later).
- Maple. A good one for bonfires and cooking fires, as it adds flavor to your food.
- Hickory. The smell many people associate with campfires.
We just spoke in passing about ‘seasoning’ the wood, and no, we certainly don’t mean adding salt and pepper; we also mentioned green wood is not ready for your fire pit. It’s time to elaborate.
Step 3: Make Sure It’s Dry
Wood from a tree that has just been felled (also known as ‘green wood’), will easily hold about 60% moisture; if you then toss it into your fire pit, two things happen: one, it won’t burn as hot as it otherwise would; and two, that moisture will turn to vapor. Both things will cause more smoke. In order to be ready for your fire pit, wood should be under 20% moisture; under 18% is even better. Here’s how to do it.
In a way, this means baking. Wood is placed into a kiln (a sort of oven), and left there at temperatures of 120 to 220°F, for a period of 3 to 6 days. You take it out, and it’s usually ready to burn (more on how to check if wood is dry enough later). The main drawback? The investment. If you manage to find a supplier whose stock is kiln-dried, they will charge you between 10 and 30% more than they would for wood that didn’t go to the procedure. Getting your own kiln will set you back a few hundred dollars if you do it yourself, remarkably more if you buy a manufactured one.
No investment here, or rather, not of the money persuasion. All you need is, an open space for your stock, and plenty of time to spare before you start your fires. In essence, what you do is place you wood in the open, and let it dry out for at least one season, hence the name. Here’s a more detailed breakdown.
- Split your logs into manageable pieces. If your fire pit literature includes an optimal size for the chunks you should put in, use that as reference; otherwise, go for about 8″ x 15″, unless your fire pit is really small.
- Spread and stack them, paying attention to airflow. For a base, a wood pallet is often recommended (and definitely don’t place them on bare earth); when stacking, try and leave space between the pieces for the air to go through.
- Set a tarp on top, unless your chosen space happens to have some sort of roof; the idea is to prevent exposure to water.
- The waiting game begins. This will vary depending on the type of wood you chose; oak, for example, can take as many as 3 years to season properly. At least one full year is commonly advised.
Which Is Better?
In general, kiln-dried is considered better, mostly because it provides a better, faster drying; your wood is ready in days, instead of months or years. If you can’t or won’t offset the cost, and you don’t mind waiting, then seasoning is a perfectly viable alternative. Whichever the alternative you pick, there’s yet another step: verifying your stockpile is ready.
How To Tell if Your Wood Is Dry Enough
Either you just got your delivery from your supplier, or you feel your stockpile has been sitting in the open long enough. Whatever the case may be, here are a few ways to find out if moisture level is where it should be.
Look at it. Dry wood will be lighter in color (gray if it’s been longer), with cracked ends and visible growth rings. Bark will come off easy, too.
Bang two chunks together. If they give off a loud, sharp crack, rather than a dull thud, then that’s a good sign.
Use your nose. No more smell of resin? Good sign.
Measure it. The most accurate alternative. A moisture meter will tell you in seconds the percentage your wood is holding, with no need for guesstimates.
Step 4: Keep It Clean
It wouldn’t hurt to give it a deep scrubbing (every 6 months at least), though the specific method will vary depending on the material your fire pit is made of (cast iron, steel, stone). Doing so benefits the fire pit itself, which is not a bad thing. Ash and unburnt bits, on the other hand, should be dealt with frequently, as they will eventually get in the way of proper airflow and, therefore, oxygen supply.
The first thing to remember: it’s best to wait for your fire pit to be completely cool before proceeding. For good measure, approach the back of your hand to the interior. If you feel no heat coming off, lay your hand down on it. Should it be completely cold to the touch, it is a good time to continue.
No matter how long it’s been since the fire died down, there may still be an ember which, if exposed to oxygen, might catch on fire. For this reason, ashes should be gathered into a metal container, never into anything cardboard or plastic (like a trash bag). A kit like this one provides everything you need: a shovel to scoop up the ashes, a bucket to pour them into, and a lid to keep them contained. A good shop vac can help you pick up anything the shovel couldn’t catch.
Disposing of the ashes should be done safely too—a snow bank in winter, or a damp area away from dry vegetation in summer, are good places to dump them into. If you can’t empty the bucket right away, be sure to keep it at least 10 feet from any wall or furniture. That said, you don’t absolutely have to throw them away: ashes have plenty of uses such as compost, de-icing, pest control and even soap making.
Step 4: Pay Attention to Structure
Building a fire is an art of its own. For your flame to begin and rise appropriately, you require three elements—and every one of them should be as dry as possible:
This is what you apply the match to, for jump starting the fire; should be materials that ignite quickly and burn easily, such as dry grass, paper towels with cooking oil, pine sap or sawdust. If you’d rather not bother with procuring your tinder, you can always buy a fire starter.
Its function is to pick up on the flame, and maintain it. It should be quick to catch on fire, and it also must go on burning longer than tinder. Some examples: rolled up newspaper, larger wood splinters, small twigs, bits of softwood such as pine. Nothing too big: if larger than a pencil or too thick to snap by hand, then it is not small enough to use for kindling.
Your carefully selected and prepared chunks go here.
Putting Them All Together
As you may have surmised by now, the idea is to begin the fire with the tinder, have it transfer to the kindling, and eventually propagate it into your firewood. Building your fire appropriately has the purpose of ensuring this process happens smoothly, and also promotes optimal airflow. This is known as a fire lay. While there are several styles of fire lay—and they all work decently—, the ‘log cabin’ is often recommended for fire pits. It is done as follows:
- Place your tinder, all bundled up, at the center of the fire pit.
- Lean pieces of your kindling against one another around your tinder bundle, creating a cone above it. Make sure to leave gaps for air to flow through, and an opening for your match or lighter to reach the tinder.
- Make the cone larger with bigger pieces of kindling and suitably small bits of firewood. At this point, you have built a ‘teepee’, a style of fire lay that is considered basic for anyone trying to learn how to build a campfire. Since we’re going for a fire that lasts longer, we ought to perform a few more steps.
- It’s time to tap into our firewood stockpile. Begin by placing two of your biggest logs on either side of the teepee, parallel to one another. Then, take a pair of slightly smaller logs and set them on the first two; they should be perpendicular to those at the bottom, and parallel to each other.
- By now you might have surmised why it is called the ‘log cabin’. Continue to stack your logs in progressively decreasing size, two by two. Each layer should be brought closer, essentially hugging the teepee within. Keep going until there’s a few small pieces at the top and there is a roof above the teepee.
- Your fire lay is finished; all that’s left to do is to reach your tinder bundle with your match or lighter.
Step 5: Don’t Overload It
As the fire goes on, you will eventually have to add more wood. When you do, don’t overdo it: adding too much wood will lower the overall temperature of your fire pit and reduce its burn efficiency. Put in one chunk at a time, and stop when your fire has regained a decent intensity.
Step 6: Consider a Smokeless Fire Pit
That’s a thing? Yes, in a way. No fire pit—especially among those that burn wood—will be 100% smokeless, but there are some that, by way of their design, boost the flow of air into the fire, which promotes a more thorough combustion, and thus the reduction of particles released as smoke. Here are a few examples:
TIKI Brand 25″ Low Smoke Fire Pit. A pretty good choice for the backyard, thanks to its looks. Made in 16-gauge stainless steel (the thickest in the market), with a black powdercoated finish to make it more durable. Offers its own line of wood pellets for a quick ignition and a 30-minute burn, which can be prolonged by adding regular seasoned firewood. Includes one bag of these proprietary pellets, a weather-resistant cover and a stand.
Blue Sky Outdoor Living PFP1513 Smokeless Portable Fire Pit. As the name implies, this one is made for taking along in camping trips. It consists of 2 pieces, which can form a fire pit or nest into one another for transport depending on how they are brought together. Includes a bag for carrying.
Solo Stove ‘Bonfire’ Portable Fire Pit. Another compact, lightweight design, built with cooking in mind. This one is a single piece, no assembly required. The accessories for using it as a stove (as well as spark screen and cover) must be purchased separately.
Whenever you light up your fire pit, smoke doesn’t have to be a problem. Just choose the right firewood—and make sure it’s not holding a lot of moisture—, keep your fire pit clear of debris, build your pile appropriately, and you should be good to go. There’s nothing wrong with choosing a fire pit designed for reducing smoke to a minimum, if it comes to that. Here’s to the many happy memories to come!