When building an in-ground fire pit, ventilation is one of the most important things to consider. However, many people don’t know they must meet specific regulations to have a functional and safe in-ground fire pit. But that changes now.
Every firepit needs proper ventilation to ensure that the fire burns continuously and doesn’t harm those around it. Most jurisdictions require that you have at least one vent at the bottom half of the fire pit. And the idea is to let the hot air and unburnt fuel out.
This article will cover everything you need to know about in-ground fire pit ventilation, from the legalities of fire pit ventilation—to the different ways you can ventilate your fire pit. By the end, you’ll be an in-ground fire pit ventilation expert.
What the Law Says About Fire Pit Ventilation
In addition to being a safety hazard, an improperly ventilated fire pit can also be a legal liability.
Most jurisdictions have laws about open flames and outdoor fires, and these laws usually require some form of ventilation for all fire pits. The recommendation is to have at least two vents of a minimum size of 18 square inches (116 square cm) each. These are supposed to allow heat and residual fuel to escape.
The law also says you should install the vents in the firepit’s mid to lower area. This procedure means using a non-flammable pipe and floor trap to get the job done.
You should also ensure that you place your vents at least 3 feet (0.91 meters) away from trees, shrubs, or other combustible materials. This distance will help prevent fires from embers that may escape through the vents.
The last thing you want is to get in trouble with the law because of your fire pit, so it’s essential to make sure that you meet all the requirements.
What Is Fire Pit Ventilation, and Why Do You Need It?
To understand why ventilation is essential for in-ground fire pits, you first need to know how fire works.
As you probably know, fire needs oxygen to survive. This requirement is why open flames will eventually go out if left in a sealed container—the oxygen depletes, and there is nothing left for the fire to consume.
The same can happen when you build a fire in a partially closed space, like an in-ground fire pit. The fire will burn lazily or need constant attention if there is insufficient ventilation. This issue is vital for propane-powered fire pits, which require a lot of oxygen to function correctly.

Then there is the issue of disposing of unburnt fuel and smoke. When you have a fire in an enclosed space, the smoke and unburned fuel have nowhere to go but up. This build-up can be a severe problem if the smoke if you do not provide ventilation out of the fire pit.
To avoid this, you must ensure that your fire pit has enough ventilation—this will allow the fire to burn at a safe temperature and prevent it from going out.
Types of Fire Pit Ventilation
Now that you know why ventilation is so essential, it’s time to look at the different types of ventilation you can use for your in-ground fire pit.
There are two main ways to ventilate an in-ground fire pit: natural and forced ventilation. Let’s explore these options in greater detail.
Natural Ventilation
Natural ventilation is when the fire pit is open to the air, like a traditional campfire. You can achieve this by digging a bigger hole than you need for the firepit, giving it breathing space all around. This process allows the fire to draw in oxygen from the surrounding area and prevents it from getting too hot.
Forced Ventilation
Forced ventilation is when you use a fan or other mechanical device to move air into the fire pit. This ventilation type is usually necessary for in-ground fire pits with no space between its sides and the earth. In this case, you can connect metal tubing at the recommended height and angle to the outside of the fire pit.
The most important thing to remember is that you should install at least two in the lower part of the fire pit. This method will allow the hot gases to escape and prevent the fire from getting out of control.
How To Build a Safe and Legal In-Ground Fire Pit
Now that you know everything there is to know about in-ground fire pit ventilation, it’s time to put that knowledge to use.
Before we dive in, here’s a quick video for reference when building an in-ground fire pit that we think you might enjoy.
Building a safe and legal fire pit is not tricky, but there are a few things that you need to keep in mind.
- Get the proper permits. In most jurisdictions, you will need a license to build an in-ground fire pit.
- Choose the right location. The best spot for an in-ground fire pit is on level ground at least 10 feet (3 meters) away from any structures or other combustible materials. These include things like trees, wood fences, and decks.
- Choose an appropriate size. The fire pit should be at least 2 feet (60 cm) wide and 2 feet (60 cm) deep. It should also have a base of at least 4 inches (10.16 cm) of concrete or other non-combustible material.
- Install proper ventilation. This procedure means putting in at least two vents that are at least 18 square inches (116 square cm) each. You should place these vents in the lower part of the fire pit.
- Make sure that you have a way to extinguish the fire. A water hose or fire extinguisher should be closed if the fire gets out of control.
Tips for Using Your Fire Pit Safely and Effectively
In case you have a safe and legal fire pit. Here are a few tips to help you get the most out of your in-ground fire pit, especially if you choose to go with a wood-burning fire pit.
- Select only dry wood: Wet wood produces a lot of smoke and can be difficult to ignite—which can be a problem if you’re trying to roast marshmallows or cook hot dogs. You also don’t want to use treated wood, as the chemicals can be released into the air when it burns.
- Build a small fire: A big fire might look impressive, but it’s unnecessary. A small fire will provide enough heat and light for most situations. Plus, it’s easier to control.
- Never leave the fire unattended. Make sure someone is always there to watch the fire to monitor whether it gets out of control. However, this person cannot be a minor. You won’t believe how many accidents happen yearly because someone left a fire unattended.
- Extinguish the fire properly: When you finish using the fire pit, ensure you extinguish the fire before leaving. The best way to do this is to pour water on the ashes and stir them around. You can also use sand to smother the fire.
By following these tips, you can be sure you’re using your in-ground fire pit safely and effectively.
Final Thoughts
Building an in-ground fire pit is a great way to enjoy the outdoors, but it’s essential to do it safely. And ventilation is one of the most important aspects of a safe fire pit.
Make sure you have two vents at least 18 square inches each. You should place these vents in the lower part of the fire pit.
Also, make sure that you have a way to extinguish the fire. A water hose or fire extinguisher should be within reach if the fire gets out of control.