You’ve picked out the perfect fire pit, maybe even some comfy Adirondack chairs. You’re so ready for those chilly evenings gathered around the flames. But what if those flames are weak and sputtering, or worse, dangerously high? That’s where this guide to gas line sizing comes in. It’s the key to a safe and enjoyable fire pit experience.
The biggest mistake that we see people make for gas line sizing is not running a large enough gas line. Another common error is choosing a burner that operates at a much higher BTU rating than their line, gas meter, or LP tank can supply. The Crossfire burners operate well even at 70% of the fuel capacity. For example, let’s say you only have 150K BTUs available, but you want to purchase a 180K BTU burner. Will you still get great flames? Yes. The Crossfire burners by Warming Trends are extremely efficient and utilize the BTUs incredibly well.
You see, it’s not just about picking a cool burner. It’s also about making sure your gas line can actually feed those flames the fuel they need. Don’t worry, though! In this guide to gas line sizing, we’re here to break it down and make sure you get it right.
Why Gas Line Size Matters

Think of your gas line like a straw. If you’re sipping a milkshake through a tiny coffee stirrer, it’s going to be a slow and frustrating process, right? The same goes for your fire pit. Too small of a gas line restricts the flow of fuel to your burner, leaving you with weak, underwhelming flames.
Here’s the deal: Your fire pit burner has a BTU rating (British Thermal Units), which tells you how much heat it produces. Your gas line, on the other hand, has a limit on how many BTUs it can deliver. If your line is too small, it won’t be able to keep up with your burner’s demand.
Decoding the Charts
To help you get a rough estimate, we’ve got some handy charts that are a good guide to gas line sizing:

How to Use Them:
- Find your distance: Look in the left column for the distance (in feet) from your fire pit to the fuel source (your gas meter or propane tank).
- Check your pipe size: In the top row, find the size of your gas pipe (e.g., 1/2″, 3/4″, 1″).
- Match it up: Where the row and column intersect, you’ll find the approximate number of BTUs that can be delivered through that pipe size at that distance.
Let’s illustrate how to use these charts with an example. Imagine you have a propane fire pit positioned 20 feet away from your propane tank, and you’re using a 1-inch diameter pipe for the gas line. Referring to the propane chart, you’ll find that this configuration can deliver approximately 732,000 BTUs. This means your fire pit can comfortably handle a burner with a BTU output within that range.
It’s crucial to remember that these charts offer estimates. For precise calculations tailored to your specific setup, it’s always best to consult a qualified gas professional. They can accurately assess your needs and ensure your gas line is properly sized and installed. There may be pieces to this puzzle that you haven’t considered yet, such as gas line material. Also, keep in mind that every fitting (elbows, tees, connectors, etc.) in your gas line adds to its effective length and slightly restricts gas flow. A good rule of thumb is to add 5 feet to the total length for each fitting when using the charts.

Finally, if your fire pit shares the gas line with other appliances like a grill, water heater or furnace, this will impact the total BTUs available for your fire pit when they’re in use. Factor in the BTU requirements of all appliances on the line to ensure adequate gas supply for each.
Beyond BTUs: Pressure is Key
While BTUs determine the volume of fuel your fire pit receives, gas pressure dictates how forcefully that fuel is delivered. Think of it like this: you need enough “oomph” to push those BTUs through the gas line and into your burner.
For optimal fire pit performance, aim for the following gas pressure:
- Propane: 11-13 inches water column (w.c.)
- Natural Gas: 7-10 inches water column (w.c.)
“Water column” is simply a unit for measuring gas pressure when it is less than 1 PSI. You don’t need to delve into the technicalities, but it’s important to know that incorrect pressure can significantly impact your fire pit’s flames. If the pressure is too high, you might experience a noisy whistle and “blowtorch” effect, and in some cases, it can even be dangerous. On the other hand, if the pressure is too low, your flames will be weak, small, and less impressive.
Ensuring the correct gas pressure, along with proper BTU capacity, is essential for achieving that perfect, mesmerizing fire pit experience you’re after.
When in Doubt, Call a Pro!

While these charts provide valuable guidance for understanding gas line sizing, it’s crucial to remember that they don’t replace the expertise of a qualified gas professional such as a plumber or HVAC contractor. Gas lines are serious business, and safety should always be the top priority.
A professional can accurately assess your fire pit needs because they have the expertise to consider more than just the standard charts. They understand that different pipe materials affect gas flow – for example, black iron pipe is smoother than corrugated stainless steel tubing, allowing for easier gas movement. They also know that the gas pressure supplied to your home can vary, which influences how much gas reaches your fire pit.
Furthermore, a professional will factor in your existing gas appliances. If you already have a gas furnace, water heater, or stove, these appliances use some of your available gas supply. That can potentially limiting the amount that can be dedicated to your fire pit. By considering all these factors, a professional ensures your fire pit installation is safe and efficient.

Sometimes attempting to size and install gas lines yourself without proper expertise can lead to dangerous consequences, including gas leaks, fires, and even explosions. A qualified gas professional can accurately determine your BTU availability. They can also ensure your fire pit is set up for optimal performance, and most importantly, guarantee a safe installation that adheres to all local codes and regulations. Therefore, always remember: safety first! Before embarking on any gas line installation or modification, consult with a qualified plumber, HVAC technician, or propane supplier. Their expertise will provide peace of mind and ensure a safe and enjoyable fire pit experience.
With the right guide to gas line sizing, you’ll be well on your way to enjoying those cozy nights by the fire. So, grab your tools, consult with a professional, and get ready to create memories around a fire pit that’s both safe and spectacular!