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Helpful Tips for Planning a DIY Propane Fire Pit / Table

 

Building a DIY propane fire feature, whether it be a fire table or a fire pit, can be both a lot of fun and a bit intimidating when starting your project.  Not to worry, Celestial Fire is will help guide you through the entire project.  We are available both online and by phone to support you and your project.  On this page we’ve put together a lot of information we believe you should know going into your project.  By having a good understanding of the fundamentals and how they apply to constructing a fire feature will help ensure you build a fire feature which not only looks amazing but operates safely.

CAUTION! Installing gas appliances can be dangerous. We advise working with a certified Gas Installer.

Some quick tips from Mike for installing a liquid propane fire pit burner

Propane is Heavier than Air – Design for safe and proper ventilation

The most important thing to know and consider in your design is that propane is a very heavy gas. Propane is heavier than air and will always settle downwards.  It can fill your burner pan with gas before igniting leading to a large initial combustion/flame.  It can also fill the enclosure under your burner pan with gas which can be very dangerous.  For this reason, you need to have adequate ventilation in the lowest parts of your enclosure to allow any propane gas which leaks into it to drain out of the enclosure.  Think of propane as water when planning for ventilation.  With propane you should have 200 square inches of ventilation located in the lowest portions of your enclosure.  The design we recommend for propane enclosures is to leave the bottom of the enclosure open and have it raised an inch or two off the ground.  If you plan to have your propane tank in the enclosure you can add a support shelf for the tank to keep it off the ground and out of sight.

PROPANE has 3 carbon atoms and 8 hydrogen atoms (C3H8) – NATURAL GAS has one carbon atom and 4 hydrogen atoms (CH4).  50% more carbon in propane makes it heavier than air while natural gas remains lighter than air. 

Propane Burns Dirty – How to minimize the soot left behind by propane

As noted in the previous section, propane has a much higher carbon content than natural gas.  This means that it’s much more likely to leave a soot deposit behind due to the carbon not burning completely.  The soot will show as a black covering on the fire glass, or around the edges of the burner pan.  There are two things you can do to limit how much soot is left behind.  The first is to add air to the propane by installing an air mixer just prior to the burner.  This will help the flame to burner hotter and cleaner.  The second thing you can do is add a glass flame guard around your burner.  The flame guard will protect your flame from the breezes which can blow the flame away from the gas from blowing the flame around the fire feature and ensure more of the gas burns completely.  If you see soot on the edges of your burner pan this is a sign that you need to add a glass flame guard.

If you do get some soot from your propane fire feature, don’t worry – it’s easy to clean.  Some people will leave their fire feature uncovered during a couple of rainy day and let nature do the cleaning.  Or you can rinse the soot off using a 50/50 mixture of water and vinegar.

YELLOW flames burn ambient air, BLUE flames burn air which is mixed with the gas.

Gas Fittings – Tapered Thread vs Flared

There are two common type of fittings for gas; NPT (National Pipe Thread – or also referred to as National Pipe Taper) and flared (compression).  The two fitting types are very different and cannot be connected directly together without a coupling to make the conversion; however, it is common to have a mix of flared and NPT components used in fire features.

NPT uses a tapered thread to provide a seal.  Since the threads are tapered the tighter you tighten the fitting the tighter the seal becomes.  Because the seal is made by the threads you need to use Teflon gas tape on the threads.   Gas rated Teflon tape is usually a yellow color.

Flared fittings have a flared surface on the tip of the fitting which is pressed against a matching inverted flare to provide a seal.  The seal is contained to where the two flares meet, the threads do not contribute to the seal.  With a flared fitting the function of the threads is only to apply pressure to the flare where the seal is made.  The threads themselves do not contribute to the seal, as such you should not apply any Teflon tape or other sealant to the threads of a flared fitting.  

NPT sizes are loosely based on the inside diameter of the gas pipe.  As such, 1/2” NPT threads actually measure 0.840”. 

Burner Options – Selecting the best type of fire pit burner for your project

Depending on your project you’ll want to choose the burner option which best matches your needs.  Typically, there are two options to choose from; a stand-alone burner ring or a burner and pan kit.  Burner rings are a good option if you already have a pan or bowl to install it into.  Fire pit burner pans with a burner included are a great option because they include the burner with a pan which can easily be dropped into place.

Stainless steel burner rings are a great option for gas fire pit projects where you don’t require a pan under the burner to support the fire glass or lava rocks.  A good example is converting a bird bath to a fire feature, fire bowls, and paver stone fire pits.  Celestial burner rings come in a reversable design where they can be installed with the holes facing upwards or downwards.  With propane you always want the holes facing upwards because the propane is heavier than air and requires a push to send it up to the flame area.

Drop-in burner pans are the best thing since sliced bread.  They make installing a burner into a tabletop very easy and leave you with a professionally installed appearance.  Drop-in burner pans include a burner pre-installed into a burner pan which simply needs to be dropped in place.  The lip of the pan provides support and the weight of the pan holds it in place. There’s no need to fasten the pan to the surface it’s installed into.  When planning for the burner pan installation, the cut-out for the burner pan should be about 1” larger than the drop-in portion of the pan.  For example, a 24” x 8” burner pan should have a 25” x 9” opening to drop into.  This will allow the pan to easily fit into place and for temperature expansion and contraction.  For smaller pans such as the 24” x 8” you can get away with an opening which is only 1/2” larger than the pan (24-1/2” x 8-1/2”) because the pan won’t expand much when heated.  With longer pans the expansion is more significant, such as the 48” x 6” pan.  Here we recommend the full amount of 1” for the length (49” length opening).

For an easier installation, and safer operation, we recommend installing a CSA certified burner kit.  CSA (Canadian Standards Association) burner kits are complete kits which are certified both for mechanical and electrical safe operation.  Since these kits are tested for safety, they are a complete system with all the components installed and only require you to attach to a propane tank.  They include the burner, pan, igniter, thermocouple (flame sensor), hoses, regulator and control knob.   

Some key factors to know when considering a CSA burner kit:

  • CSA certification is required for commercial installation
  • CSA certification may be required by local licensing and permit offices (we highly recommend for shared use such as Airbnb and VRBO rental properties)
  • CSA burners have a lower BTU rating as the flame height is limited for safety

A THERMOCOUPLE is a safety feature on CSA burners which will turn off the gas if it senses the flame is no longer burning.  It can be identified as a metal rod inside a cage and will have a single flame directed at it.

Propane Gas Hose Options

There are several options when selecting gas hoses for your fire feature.  Most connection kits will include the hoses which will be either a rubber hose or stainless-steel flex hose.  If the hose will be located where it may be cut or damaged, such as by a weed trimmer, then you should opt for a flex hose.  If the hose will be in a cabinet or an area where there’s no danger of it being cut rubber is sufficient.  But beware that not all flex hoses are equal.

  • Standard Flex Hose – Standard flex hoses should be avoided.  These hoses have ribs which are evenly spaced along its length which can cause a whistling noise.  This is because the even spacing of the ribs causes an oscillation effect, which results in a high-pitched whistling sound. 
  • Whistle-Free Flex Hose – Whistle free flex hoses prevent the whistling noise often heard in flex hoses by changing the rib spacing at various lengths along the hose. The change in rib spacing prevents sound from oscillating and creating a whistling sound.
  • Rubber Gas Hose – The most common type of hose is a standard rubber gas hose. These won’t whistle, since the inside of the hose is a smooth surface without any ribs. Rubber gas hoses typically come with most propane regulators and connection kits. 

Most DIY burners have 1/2″ NPT fittings, the hoses used for these projects are usually 3/8” with a flared fitting.  This is not a problem as a 3/8” hose can deliver more than enough gas to operate your fire feature.  

Regulators and Gas Pressure 

A regulator is required to reduce the high pressure of your propane tank to the much lower pressure the fire feature requires for operation.  Broken down to a simplistic overview of how a regulator works, a regulator contains a spring-loaded diaphragm which will adjust the size of the gas input based on the line pressure.  As the pressure rises in the output line to your fire pit the diaphragm will push back on an input valve restricting the amount of gas entering the regulator.  As the line pressure in the regulator drops the diaphragm opens the input valve from the tank keeping the pressure at the desired level.  

Most propane fire features use what’s called a single stage regulator.  A single stage regulator drops the gas pressure from the tank in a single step.  Single stage regulators are affected greatly by drops in supply pressure (tank pressure). This isn’t usually a problem with fire pits as it’s easy to access and adjust the control valve occasionally to keep the flame at the desired height.  Two-stage regulators reduces the tank pressure in two steps.  With this design the two-stage regulators are much better at maintaining the line pressure as the tank pressure drops and eliminating the need for periodic adjustments of the flame height. 

The pressure required for propane fire features is between 7” WC and 11” WC (water column).  Water column is the amount of gas pressure required to raise water in a vertical tube a given distance.  As a frame of reference, 28 inches WC is equal to 1 PSI.  The pressure required for propane fire pits is higher than propane BBQ grills, so want to purchase the correct sized regulator for your project.  

Propane fire pits require a pressure between 7” WC and 11” WC.  If your flame height is low you likely have a grill regulator. Upgrade to a high-pressure regulator to fix the flame height.

Options for Connecting to Your Propane Tank

There are two common ways to control the flame height; with a key valve or with an adjustable regulator.  If you want a basic installation where you control the flame at the propane tank you can install a high-pressure adjustable regulator which goes from 0 to 20 psi.  This is the quickest and easiest installation.  If you want to control the flame at the fire feature you can install a key valve.  A key valve is a gas ball valve which comes with a key to turn the valve on and adjust the flame height.  Key valves require you have a cabinet or other structure to install the key valve into.  To install using a key valve we recommend you purchase a connection kit which includes the key valve, regulator, air mixer and hoses.  This will provide everything you need to connect your burner to the propane tank.

If you’re installing a CSA certified burner kit you don’t need to purchase anything to connect it to your propane tank.  Everything is included including the regulator, air mixer, spark igniter, thermocouple, control valve and hoses.

If you’re installing a CSA certified burner kit you don’t need to purchase anything to connect it to your propane tank.  Everything is included including the regulator, air mixer, spark igniter, thermocouple, control valve and hoses.

CELESTIAL SUPPORT
We’re here to help you with the installation of your Celestial DIY fire pit components. Available by phone M-F, 8:00 AM to 5:00 PM Eastern Time or by email.
(301) 245-7755
Support@CelestialFireGlass.com

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