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How Long Does a Propane Tank Last for a Fire Pit

Have you ever found yourself curled up by a fire pit wondering, “How long will my 20-lb. propane tank last on a fire pit?” Well, you’re not alone.

It’s a burning question for many, especially when the flames are flickering in the middle of a beautiful evening.

This guide will help you understand how long you can use your propane tank, what factors affect tank life and usage, and how to calculate the number of hours you can use a standard 20-pound propane tank on a fire pit.

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I am going to turn up the heat with some facts, so be sure to read the article at the end!

The Anatomy of a Propane Tank and How It Works

A propane tank is a pressurized storage vessel designed to hold propane, which is a liquefied petroleum gas. The tanks are constructed to handle the high pressures under which propane is stored, and they follow strict manufacturing standards to ensure safety. Propane tanks can vary in size, from small portable cylinders to large tanks installed underground. In this article, we are talking about small ones you can use for your fir pit table.

Within a propane tank, there are several key components:

  • Hand Wheel
  • Service Valve
  • Pressure Relief Valve
  • Overfilling Prevention Device

Figure below shows the internal construction of a typical 20 lb propane tank.

Propane Tank Anatomy
In the picture you can see what the propane cylinder is made of.

When propane is pumped into the tank, it remains in liquid form due to the pressure. Upon opening the tank’s valve, the liquid propane gets vaporized. This vapor then travels via pipelines to various appliances where it’s either burned for heating or cooking or utilized in cooling systems.

Interesting Fact

Have you ever wondered why propane (C3H8) is commonly used for many applications and not other hydrocarbons like methane, ethane, or butane? Here’s the science behind it:

  • Methane (CH4): At ambient temperature, methane remains supercritical, meaning it doesn’t easily transition between liquid and gas states. This property gives it a low energy density, making it less efficient for many applications compared to propane.
  • Ethane (C2H6): While ethane isn’t supercritical like methane, it requires significant pressurization to be stored as a liquid. This would necessitate having a regulator directly on the tank, complicating the design and usage.
  • Butane (C4H10): Butane seems to be a suitable candidate in warmer climates. However, it doesn’t exert enough vapor pressure in colder environments, rendering it less versatile than propane, especially in regions that experience varied seasonal temperatures.

In a nutshell, propane strikes the right balance in terms of its physical properties, making it a popular choice for a range of applications, from cooking to heating.

Now let’s look at what impacts how long a propane tank will last on a fire pit.

Factors Affecting How Long a Fire Pit Propane Tank Lasts

The duration of a propane tank on a fire pit can vary based on the following factors:

1. Fire Pit Dimensions & Propane Tank Size

The dimensions of your fire pit directly dictate its fuel consumption: larger fire pits demand more fuel compared to their smaller counterparts.

Correspondingly, the propane tank’s size is pivotal in gauging its duration. A more substantial tank, housing greater fuel quantities, will naturally last longer than its smaller counterpart. However, the trade-off is that larger tanks come at a higher cost.

Hence, finding a balance between tank size and frequency of fire pit use becomes essential for optimal enjoyment and efficiency.

2. The BTU Burning Rate of Your Fire Pit

The effectiveness of your propane fire pit’s heat generation hinges on its British Thermal Unit (BTU) rating. BTU measures the thermal energy necessary to raise the temperature of a pound of water by one Fahrenheit degree at sea level.

A fire pit’s flame height is intrinsically linked to its BTU output: higher BTUs translate to taller flames. Consequently, a fire pit boasting a higher BTU rating will provide more warmth, ensuring a comfortable ambiance for all attendees of your summer barbecues. Remember, propane fire pits are not only efficient but also environmentally considerate, making them a top choice for outdoor heating.

3. A Higher Setting Means the Firepit Will Use More Gas

Intuitively, operating your propane fire pit at its peak setting will consume more fuel, reducing the tank’s overall operating time. A fire pit running at maximum BTU might exhaust a 20-pound tank in about 4-5 hours, whereas a conservative setting could extend this to around 8-9 hours.

4. Impact of Weather and Climate

Environmental factors play a pivotal role in the efficiency and longevity of your propane tank. One element that might surprise you is the influence of wind. In areas susceptible to gusty conditions, you might find your propane tank depleting faster. The reason? Wind dissipates the fire’s heat, pushing the system to expend extra energy to maintain its flame.

Moreover, colder climates or extreme meteorological conditions, such as enduring winter phases or intense cold spells, escalate the need for heating, leading to augmented propane consumption and, thus, reducing the operational duration of your tank.

Another aspect to consider is the external temperature. Unbeknownst to many, a fire pit’s fuel consumption spikes during colder times because it strives to sustain a steady temperature. So, during colder months, be prepared for your propane tank to empty faster. On the flip side, in warmer conditions, your fire pit can operate more efficiently, ensuring longer tank life.

How Long Does a Propane Tank Last in a Fire Pit

On average, with a 20 lb. propane tank, your gas fire pit will stay alight between 3 and 20 hours. As we said above, the exact duration depends on your fire pit’s BTU rating – higher BTU ratings consume propane faster.

Specifically, a 20 lb. propane tank holds roughly 430,000 BTUs. By dividing 430,000 by your fire pit’s BTU rating, you can estimate the hours of burning time you’ll get.

Refer to the diagram below for an overview of the burn duration for a 20 lb. propane tank in a fire pit at heat outputs of 30,000 BTUs/hr, 40,000 BTUs/hr, 50,000 BTUs/hr, and 60,000 BTUs.

Burn duration diagram
The burn time (in hours) of a propane tank in a fire pit depends on the BTU rating – higher BTUs mean less burn time.

The diagram shows that the burn duration of a propane tank for the fire pit fluctuates based on its BTU rating. Specifically, a 20 lb. propane tank will last 14 hours at 30,000 BTU, 10 hours at 40,000 BTU, 8 hours at 50,000 BTU, and 7 hours at 60,000 BTU.

Keep in mind that the durations mentioned in the diagram serve as approximations. Your actual burn time can vary depending on the flame’s height, environmental factors, like wind can also influence propane consumption.

I made a list of the best propane fire pit tables. So read the article to learn more about different types of fire pits available on the market.

How to Calculate the Number of Hours a Tank Will Last on a Fire Pit?

To calculate the number of hours a propane tank will last, follow these steps:

  • Step 1. Determine the total BTU rating. First, list the BTU ratings of each appliance you intend to connect to the tank. Sum up these ratings to get the total BTU usage.
  • Step 2. Identify the propane tank capacity. Check your propane tank for its capacity, usually mentioned in pounds or gallons. This detail can be found on the tank label or in its manual.
  • Step 3. Compute the total BTU capacity. Multiply the tank capacity by the BTU equivalent for each pound or gallon of propane, which is roughly 91,547 BTUs for a gallon and 21,594 BTUs for a pound.
  • Step 4. Estimate Burn Duration. To ascertain how long your gas cylinder will last, divide its total BTU capacity by the combined BTU rating of your appliances. This gives you the approximate number of hours your tank should serve you.

For example, if you have a 20-pound propane tank and a fire pit with a BTU rating of 50,000 BTUs:

  1. The total BTU rating of your appliances is 50,000 BTUs.
  2. The propane tank capacity is 20 pounds.
  3. The total BTU capacity of the tank is 20 pounds * 21,594 BTUs per pound = 431,880 BTUs.
  4. The hourly burn rate is 431,880 BTUs / 50,000 BTUs = 8.64 hours.

In this example, the propane tank would last approximately 8.64 hours when using the fire pit at its maximum BTU rating.

Expert Tips to Extend the Life and Use of Your Propane Tank

Wouldn’t it be great if you could extend the burn time of your propane tank and get more out of each fill? Fortunately, there are several ways to do this. Let’s take a look at how you can maximize the use of your propane tank for longer burn times and more warm, cozy nights by the fire.

1. Regulate Heat Output

Do you remember the diagram above on how many hours lasts a 20lb propane tank across various heat output? To extend the life of your propane tank, regulate the amount of gas you release. This gas flow determines the flame size.

A reduced flow means a smaller flame, thus conserving your fuel. Adjust the propane tank’s knob to find the right setting.

2. Use a Glass Wind Guard

Incorporate a glass wind guard to maintain a consistent flame while using less propane. It safeguards the flame against wind interference.

Particularly if you’re in a breezy region, a wind guard can be essential. It not only preserves the heat but also ensures efficient fuel use, meaning a prolonged tank lifespan.

3. Switch Off When Not Needed

Always remember to switch off your fire pit when it’s not in active use. This simple habit can save significant amounts of propane over time.

4. Keep an Eye on Your Tank

Periodic checks on your propane tank can prevent potential hazards. Examine it for any signs like dents, corrosion, or other damages. Should you spot any wear and tear, consider getting a replacement for safety.

5. Routine Fire Pit Maintenance

Ensuring your fire pit is in top condition can lead to better efficiency and reduced propane usage.

  • Remove the lava rocks or fire glass to expose the gas tubes.
  • Employ an air compressor to clear out any debris, ash, or dust from the pipes.

Check the article on how to clean fire pits.

6. Store with Care

Lastly, but critically important, is the proper storage of your propane tanks. Storing them carelessly, especially when unused for extended periods or in adverse conditions, can compromise safety and efficiency. Always store tanks upright in a cool, shaded spot, avoiding direct sunlight. Enclosed spaces like garages or basements should be avoided to prevent gas accumulation.

Regular leak checks and ensuring the valve is securely closed are also vital. Proper storage practices not only mitigate risks but also maximize tank performance.

Common Questions about Propane Tanks for Fire Pits

From consumption rates to refilling locations, let’s address some common concerns related to propane tanks for fire pits.

Do Gas Fire Pits Use a Lot of Propane?

Gas fire pits can consume a significant amount of propane, depending on their BTU rating. Typically, fire pit tables have heat outputs of 30K, 40K, 50K, or 60K BTU.

How Long Does a 20lb Propane Tank Last on a Fire Pit?

As mentioned earlier, it depends on the BTU rating of your fire pit. Specifically, a 20 lb. propane tank will last approximately 14 hours at 30,000 BTU, 10 hours at 40,000 BTU, 8 hours at 50,000 BTU, and 7 hours at 60,000 BTU. Various factors, such as flame height and external weather conditions, can influence the actual runtime.

Where can I refill a 20 lb propane tank for my fire pit?

You can refill your gas tank at numerous locations, including gas stations, hardware stores, and convenience stores. Propane suppliers like AmeriGas offer both propane refills and tank exchanges at specific locations. Additionally, many U-Haul locations provide propane refill services. To locate the nearest propane refill station, conduct an online search using your zip code or consult with local propane suppliers.

Bringing Things Together

Here’s a quick recap of the insights and information shared in the article:

  • We delved into the inner workings of a gas tank, understanding its anatomy and function.
  • We explored various factors that affect the burn time of a tank: the size of the fire pit and tank, the BTU rating of the fire pit, the higher flame results in greater consumption. We also discussed how weather conditions can impact burn duration.
  • We discovered how long a 20 lb. propane tank can last with different BTU ratings: 30K, 40K, 50K, 60K.
  • We learned how to calculate the burn time of a propane tank on a fire pit table using a specific formula.
  • Finally, we learned valuable tips for extending the life of a propane tank.
Cindy Becker
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