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What Size Black Pipe for Propane- Discover the Right Size for You

Are you looking for a pipe for your propane? Then you are here at the right place. Choosing the right black pipe is crucial for ensuring propane appliances’ safety, efficiency, and optimal performance.

So, what size is a black pipe for propane? The size of the black pipe is influenced by a number of factors. For instance, the distance between the propane tank, the BTU load of the devices, and the pressure drops.

Here we are going to cover everything you need to know about your propane pipe’s size. We’ll take a closer look at the factors that determine the appropriate size for your propane line. Also, we will provide tips on how to calculate the optimal diameter for your specific needs.

What Type of Pipe for Propane?

What type of pipe you use for your propane gas tank largely depends on the type of things you are going to use. But in general, most people use black pipes or black steel pipes.

what size black pipe for propane

And there is a valid reason for this. It is strong, durable, and resistant to corrosion. Other options for propane gas lines include copper and plastic piping. However, only some states permit the use of copper or plastic lines.

So, it’s important to always follow local codes and regulations when choosing the pipe.

Factors to Consider for Propane Line Sizing

There are a few factors that play a chronic role in your pipe-sizing adventure.

Distance between The Propane Tank and home

The first consideration is the distance between the propane tank and the appliances in the home. This distance largely impacts the pressure drop that occurs as the propane travels through the line. The longer the distance, the greater the pressure drop.

So, it can impact the performance and efficiency of the appliances.

BTU load

The British thermal unit determines just how much propane your device will need. It becomes easy for you to calculate your back pipe’s size.

Pressure Drop

Pressure drop refers to the decrease in pressure. It happens as propane travels through a pipe due to the resistance caused by the length of the pipe, the diameter of the pipe, and the fittings and valves in the system.

So, if the propane line is not properly sized, there is a chance of pressure drop. It impacts the performance and efficiency of the appliances.

Type of Appliances

Different propane appliances need different amounts of gas pressure. For example, a furnace may require a higher gas pressure than a stove or oven.

LP Gas Pipe Sizing Calculator

To calculate the black pipe size, you need to follow some simple steps.

Step 1: Calculating the BTU load

Most appliances, such as furnaces, water heaters, and stoves, will have a label that lists their BTU rating. You can also find it in the user manual or on the brand’s website.

Some appliances may list their heat output in watts or joules per hour. To get the BTU rating, you need to convert these units using a conversion factor,.You can use the following formula:

BTUs per hour = Watts x 3.412

For example, you have a Furness with a rating of 1,500 watts. So, now you would multiply 1,500 by 3.412.  It equals 5,118 BTUs per hour. When you have the BTU of every device, just add those up to get the total BTU.

Step 2: Determine the Gas Flow

Now that you know the total BTU load of the appliances, you can use this to figure out the gas flow rate for the system. This is typically measured in cubic feet per hour (CFH).

Here is the formula:

Gas flow (in cubic feet per hour) = BTU load/heating value

The heating value is the amount of heat that one cubic foot of propane gas can produce. However, the heating value of propane can vary depending on factors such as temperature and pressure. But a typical value is around 2,500 BTUs per cubic foot.

So, for example, if the BTU load of your propane appliances is 100,000 BTUs, the gas flow required would be:

Gas flow = 100,000 BTUs / 2,500 BTUs per cubic foot = 40 cubic feet per hour

Step 3: Determining the Black Pipe

With BTU and gas flow, now you can determine the size from the size chart. A pipe sizing chart is a reference tool used to determine the appropriate size of piping for a given application. It is determined based on factors such as flow rate, pressure drop, and pipe length.

Pipe sizing charts typically provide tables or graphs that relate the maximum allowable flow rates for different pipe sizes and lengths. The process is done based on the pressure drop and fluid properties.

Some Appliances with Their BTU/h Capacity

For your convenience, I am going to give you some of the common device BTUs.

ApplianceBTU Rating
Standing oven65,000
Boiler unit25,000
Clothes dryer35,000
Gaslight and logs2,500
Gaslight and logs30,000

The following are automatic water heater BTU/h:

Water Heater Gallons per MinuteBTU per Hour


Here are some additional frequently asked questions you might be looking forward to.

Q: How deep is a propane pipe?

Underground propane gas lines are typically buried at a depth of 12 to 18 inches. It mostly depends on the level of vehicular traffic in the area. This depth requirement is essential because by this you can ensure that the underground gas line is adequately protected.

Q: What size is the standard pipeline?

Gas lines in some homes have a standard diameter of 3/4 inch. This size is commonly used to support major appliances. However, in other homes, there may be a combination of gas lines with diameters of 1 inch, 1/2 inch, and 3/4 inch.

Q: How much pressure is on the propane line?

The pressure in a propane line typically ranges between 100 and 200 psi. So the line can maintain the liquid state of the propane gas. However, the pressure inside a propane tank may vary slightly depending on the outside temperature.

For instance, at 70 degrees Fahrenheit, a standard 20-pound propane tank would have an internal pressure of 145 psi.


So, what size of black pipe for propane? Well, it largely depends on your appliances and their BTU rate.  So, you have to determine it from the chart based on BTU and flow.

However, working with propane is a dangerous matter. To avoid any unnecessary accidents, it would be best if you consult with professionals. And always maintain safety precautions while working with flammable gas!