Whether you’re using a drop-in burner with a pan, a burner ring, or a complete, CSA-certified burner kit to create your fire feature, the fundamentals of a natural gas installation are all the same.
First, it’s important to emphasize that you should have your gas connections made by a qualified, licensed gas installer. Working with gas is dangerous, so you want to be sure the installation is done according to local building codes and is safe to operate.
The purpose of this article is to give you a basic understanding of how a natural gas fire feature works, the components needed, and how everything fits together.
When designing your fire feature, you need to include at least two ventilation openings for any enclosed areas where gas can collect. Keep in mind that natural gas is lighter than air, so when planning the location of your ventilation points, they should be placed in the uppermost portion of the enclosure. This allows the gas to rise and dissipate.
There are two types of fittings used for gas fire features. These two types cannot be connected to each other without a “coupling” to convert the fitting types.
One type of fitting used in many commercially made fire pits and barbecue grills is the flared fitting. These are easy to identify as they have a flared tip. This flared tip is pressed tightly against an inverted flared tip to create the seal.
In this instance, the only purpose of the threads is to hold the flare tightly in place against the other flare. Since the threads aren’t providing the seal, you don’t use Teflon pipe tape when connecting flared fittings.
The other type of fitting is a tapered fitting called NPT – commonly known as National Pipe Tapered Thread. Since NPT has tapered threads, the seal is provided directly by the threads. The tighter you screw the threads in place, the tighter the seal.
For NPT fittings, Teflon gas tape is always required. In the U.S. and Canada, Teflon gas tape is designated by the color yellow for easy identification.
If you’re trying to measure existing NPT sizes, you should know that the size is loosely based on the inside diameter of the pipe and not on the actual thread size. For example, the outside thread diameter for half-inch NPT measures just over three-quarters of an inch, which is the size used for most of our burners and components.
There are two types of burners commonly used in outdoor fire features.
The first type is a burner ring. Burner rings provide a flexible option for many fire pits, such as a fire pit made with pavers or a custom fire bowl.
These rings are reversible, meaning you can install the burner with the holes facing upward or downward. This is only an option with natural gas because it is lighter than air and the gas will quickly rise regardless of which way the holes are directed. (Some people like to install the holes downward to avoid rainwater getting into them. Of course, this and much more can be avoided by using a stainless steel fire pit burner cover over the burner pan.)
The second type of burner, which is the most popular and easiest to install, is a drop-in burner pan. Drop-in burner pans are a great choice for fire table designs because they include the burner and a pan in one assembly. This makes installation a breeze.
Burner pans are installed by placing them into a cut-out in your tabletop that’s about an inch larger than the pan size. This will provide an extra half-inch of spacing on all sides around the drop-in portion of the pan. That way, it can be easily placed into the cutout. Plus, the extra space allows for expansion and contraction during heating and cooling.
Drop-in burner pans are held in place by their own weight, so other than dropping them in place, there’s no other work required to mount the burner pan. The burner pan has a 1/2-inch NPT male fitting on the bottom to connect it to the gas supply line.
Natural gas fire pits require a gas pressure of between 3.5 – 7 inches Water Column. Water column, commonly referred to as WC, is the amount of gas pressure required to raise water in a vertical tube at a given distance.
As a frame of reference, 28 inches WC is equal to 1 PSI. Therefore, 3.5 inches WC is one-eighth of a PSI, and 7 inches WC is one-quarter of a PSI.
The gas pressure in the supply line of a house typically runs around 7 – 15 inches WC, which is powerful enough to distribute gas throughout the dwelling. However, it is probably too high to operate your gas appliances.
Therefore, your licensed gas installer will likely need to install a natural gas regulator to reduce the pressure coming from the house supply line and heading into your fire pit. While natural gas fire pits have a range requirement of 3.5 – 7 inches WC, the ideal pressure is closer to the 3.5.
If the pressure is too high, you can get a whistling noise from the key valve. This is because the key valve will try to reduce the pressure by passing the high-pressure gas through a small hole.
There are several types of hoses used for gas within an appliance.
Standard flex hoses have evenly spaced ribs along the length of the hose. This type of hose should be avoided, as it can cause a whistling noise. The even spacing causes an oscillation effect, which results in a high-pitched whistling sound. Not what you want to hear when you’re trying to relax by your fire pit!
A whistle-free flex hose is designed to prevent whistling noise by changing the rib spacing at various lengths along the hose. The change in rib spacing prevents the oscillation effect that causes the whistling sound.
The most common type of hose is a standard rubber gas hose. These won’t whistle, since the inside is a smooth surface without any ribs. Rubber gas hoses typically come with most natural gas connection kits.
Ignition and Flames
To turn the gas on and control the flame height, you’ll need a key valve. The key valve is a ball valve that mounts flush in your fire pit cabinet and uses a key to access the valve.
To light your fire pit, you have two options: a standard butane stick lighter or a spark igniter. The spark igniter mounts into the drop-in burner pan using the optional plate that came with the pan.
There are many natural gas connection kits available. Our Celestial Natural Gas Connection Kit includes the hoses and key valves needed to make your gas connection. It does not include the natural gas regulator or spark igniter, but these are also available from Celestial Fire Glass.
Another option is to purchase a CSA-certified fire pit burner kit. This complete kit is CSA-certified for safety and includes almost everything you need. It has the pan and burner along with the hoses, flame control knob, spark igniter, and thermocouple (flame sensor for safety).
The spark igniter and thermocouple are located inside a little box that looks like a cage. There’s a hole directing the gas at the spark igniter, which enables the flame to light as soon as the gas is turned on. The thermocouple is a safety feature—if it doesn’t sense the heat of the flame, it will turn the gas off. The CSA kit doesn’t include a pressure regulator, but your installer will likely have this part readily available.
Give Us a Call
The Celestial Fire Glass Tech Team is committed to the success of your project. If you need help determining what parts you need or how to install them, or if you want to troubleshoot a problem – give us a call. We’re happy to assist!
Our team is based in Frederick, Maryland. They’re available Monday through Friday, 8 a.m. to 5 p.m. Eastern Time by calling 301-245-7755.