Supplying the correct gas pressure for your outdoor gas fire pit will ensure that you get full enjoyment from your fire feature. When designing and planning your gas fire pit, knowing the correct pressure for the gas type you’ll be using and how to best achieve it, is vital.
In this article, we’ll give you a good understanding of gas pressure for both natural gas and propane gas in regard to outdoor gas fire pits and fire tables.
Water Column (WC) versus Pounds per Square Inch (PSI)
There are two standards for measuring gas pressure. Low pressure is usually measured in water columns (WC), and high pressure is measured in pounds per square inch (PSI). Understanding these two standards will ensure you get the right pressure for your gas fire pit.
Water Column (WC)
Water column is more accurate at measuring gas pressures lower than 1 PSI, and therefore, has become the standard for measuring lower values.
WC is the amount of pressure it takes to lift water in a tube a given distance. WC is measured in inches. For example, 1 PSI is equal to 28” WC. This is to say that if water was placed in a vertical tube and 1 PSI of pressure was applied to the bottom of the tube the water in the tube would be raised by 28”.
Gas fire pits and fireplaces require pressure in the range of 3” WC to 14” WC. 3” WC is equal to 3/28 psi. Imagine trying to measure this in PSI, which is about 0.107 PSI.
In contrast, a larger number is quite a bit easier—14” WC equals 14/28 psi, which is 1/2 psi.
You can see how WC makes measuring lower gas pressures easier for appliances such as gas fire pits.
Pounds Per Square Inch (PSI)
PSI is the most common pressure standard and is used for measuring higher pressures. We inflate our tires to 32 PSI. Can you imagine inflating tires to 896 WC? Airplane tires are inflated to about 200 PSI – or 5,600 WC.
Natural gas is delivered to your house typically around 60 PSI. A regulator at your house will reduce that pressure to between 1/4 PSI and 1/2 PSI.
There are some installations that use a higher value (2 PSI). This is mostly used in commercial buildings, but is also being used for some houses in newer developments.
Natural Gas Pressure for Gas Fire Pits
Outdoor gas fire pits and fireplaces, usually require a pressure that falls between 3.5” WC and 7” WC. Typical regulators have an output between 3” WC and 5” WC, which is the optimum pressure range for gas fire pits.
The recommended gas pressure for NATURAL GAS fire pits is 3.5” WC to 7” WC.
Celestial Fire Glass offers a natural gas adjustable regulator designed for outdoor gas fire pits, though we strongly recommend you have a licensed gas professional install your regulator.
Propane Pressure for Gas Fire Pits
Propane requires a higher pressure than natural gas. The ideal pressure for propane gas is between 7” WC and 11” WC. If you have a whole-house propane tank, you’ll want to install a regulator that delivers gas in this pressure range.
The recommended gas pressure for PROPANE fire pits is 7” WC to 11” WC.
If you’re connecting to a standard, 20 lb. propane tank (like you use for your outdoor grill), you’ll want to use a high-pressure regulator. This is different than the regulator you use for your barbecue grill, and they should not be used interchangeably.
Low-pressure regulators designed for your grill, support a flame height of 1” to 2” at most. A high-pressure regulator designed for propane fire pits will deliver the higher pressure needed in order to produce higher flames and more heat for your fire pit.
If you purchase a regulator from a reputable company that specializes in DIY gas fire pits, you’ll get the right one. If you order randomly online, pay close attention to what you’re ordering to make sure it’s sufficient. Or better yet, keep it simple and order from Celestial Fire Glass—we carry the correct propane regulators for outdoor gas fire pits.
Propane and Outdoor Temperatures
If you’re using a 20 lb. propane tank, you should understand how the outdoor temperature can affect the performance of your gas fire pit. Propane tanks store the propane under pressure in a liquid state. The liquid must change to gas in order to be used as fuel. This process utilizes heat to convert the liquid to a gas.
The more gas that is being discharged at a high rate, the more heat that is needed. Since the tank is outdoors, the ambient temperature affects the amount of gas that can be supplied by the tank. This is particularly critical with a small, portable tank.
For example, if it’s really cold, there may not be enough warmth to convert the liquid to gas in large quantities. This will result in a small flame or a flame that diminishes over time.
It’s good to know, but it isn’t likely to be a huge issue for you because if it’s that cold, you’re not likely to be outside sharing drinks with friends anyway!
Whenever dealing with gas installations, always seek the services of a licensed gas installer to ensure the safety of your project. A quick, online search of local plumbing companies will yield numerous results for locating a certified gas professional in your area.
As always, feel free to contact us if you have any questions. The Celestial Technical Team is available Monday – Friday, 8 a.m. to 5 p.m. Eastern Time.