Understanding Parts of a Propane Tank – From Gauges to Regulators

An image of a hand touching the valve of a propane tank.

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If it is your first time using propane to power your home, the propane tank may appear challenging. This is especially the case for large backyard or underground propane tanks. Propane tanks have multiple connections and accessories, including valves, gauges, and regulators.
These parts of a propane tank are not only crucial for its safe usage, but it is easy to understand their functions. So whether you are a first-time or experienced user, there is plenty to learn from this article. We will discuss the parts of a propane tank, the fittings of a propane tank, propane tank standards, and much more. Read to learn more.

Understanding Your Propane Tank

Household propane tanks are of different types and sizes. Common types include vertical tanks and horizontal tanks, also known as torpedoes. As for sizes, they can range from 20 lb to over 2000 thousand capacity tanks. 

Choosing the type and size depends on the user’s needs. Larger homes with more appliances will require larger tanks than smaller ones. 

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A standard propane tank is a structure with several parts essential for operation. The parts of a propane tank may depend on the type and size of the tank. For example, 20lb cylinders do not have some parts found in the underground or the backyard tanks. 

Generally, home-use propane tanks are designed with valves, gauges, and other fittings. Valves have different functions depending on their use in the propane delivery system. Gauges measure the amount of propane in the tank. We will delve into more details about these parts of a propane in detail below.

What Are the Parts of a Propane Tank Valve?

A gas tank system contains several propane tank valves for various purposes. Below are some of the most common and their uses.

Fill Valve

The propane tank valve allows the unidirectional flow of gas into the tank when the attendant pumps in gas. The fill valve is attached to the delivery truck fuel hose. And it has a pressure activation mechanism to open in response to tank pressure from the delivery hose.

That aside, the valves have gaskets to avoid leaks as the gas flows in from the hose. Once the personnel finish pumping in gas, that’s it! The gas cannot escape unless the gasket or the entire valve is faulty.

Safety Relief Valve

The safety relief is one of the critical propane tank valves. The valve helps with the safe operation of the propane system. That is why it is a statutory requirement to have all types of propane gas tanks fitted with safety relief valves. 

Also known as the pop-off valve, or pressure venting, the relief valve’s purpose is to release excess gas from the tank. In other words, it is a safeguard mechanism to prevent the propane tank from bursting from excess pressure build up in the tank.

Its power lies in a spring that keeps the propane tank valves shut until the pressure inside the tank exceeds the required level. At that point, the valve automatically opens to vent off the excess pressure.

Often, this produces a hissing or a pop sound, depending on the level of the excess pressure. If this propane tank valve releases the pressure with a hissing sound, the pressure build is low. On the other hand, a pop sound denotes high excess pressure build-up. 

So next time you hear this sort of sound, do not panic. You now know what it is. Once the pressure level resumes, the valve closes once more.

Service Valve

The service valve opens or shuts off the gas flowing into the appliances in the house. It is another of the propane tank valves. It acts as a control link between the propane tank and the appliances. If you suspect gas leaks based on the smell of propane, turn this valve off immediately. 

The service valve is usually fixed on top of the tank and looks like a dial, and works like a water faucet. All you have to do is turn the wheel clockwise to switch it off and anti-clockwise when turning it on.

What Are the Fittings of a Propane Tank?

Propane tanks have several fittings installed with the tank in the factory. They all cater to different propane tank needs, which we will discuss below.

Propane Regulator

A propane tank regulator is an accessory that controls the propane flow to the appliances. Without the house propane regulator, the gas is not safely usable by the appliance.

The propane tank regulator works through a pressure relief mechanism to lower the pressure to safely usable pressure levels. No wonder its function compares to how the heart regulates blood flow in the body.

Keep in mind all house propane regulators are not made equal. Their capacities can be as low as 10 psig(pounds per square inch gauge) to 200 psig. But generally, the average home-use propane regulator is less than 10 psig

Remember, different appliances require various gas pressure needs. As such, there are a variety of propane tank regulator capacities to cater to the needs of these devices. 

This aspect dictates the house propane regulator type and where to fix it in the propane gas delivery system. Sometimes, the manufacturers place them in a series depending on the needs of the particular device. 

Below are a few types of propane tank regulators.

  • First stage regulators
  • Second stage regulator
  • Integral two-stage regulator
  • Automatic change over
  • High-pressure regulators
  • Adjustable high-pressure regulators

Always ensure safety when replacement of the house propane regulator replacement is required. Only order from verified sources to avoid possible hazards.

Propane Gauges

The propane gauge shows the current amount of propane in the tank. The gauge has two parts; the internal part inside the tank and the one above it. 

How does the propane gauge work? The arm inside the tank rises and falls with the changes in the level of propane in the tank. And through a mechanism, the arm transmits the reading to the external dial of the gauge. If the level goes down, the gauge dial drops showing lower reading and vice versa.

These figures appear on the regulator dial as percentages spanning from 5 to 95. To get the exact amount of propane in the tank, simply convert it into gallons. For instance, if your 500-gallon tank shows it is at the 60% mark, the tank is currently holding 300 gallons. That is 0.6 x 500=300 gallons.

Note, the gauge readings are in percentages and therefore not precise, but at best approximations. Additionally, the moving part inside can sometimes wear out over time, increasing inaccuracy. Of course, the gauge can be repaired or replaced only by qualified personnel.

POL Fitting

POL is one of the oldest types of propane tank connectors. It is mostly found on LPG gas cylinders, although they are fitted in other propane tanks too. The name POL comes from the company that invented it – Prest-O-Lite.

To connect the POL propane connectors, screw the male connector into the female valve fitting through the left-handed(reverse) threads. This task requires a wrench to turn the hexagonal nut to apply enough force to achieve a tight seal.

This method isn’t user-friendly since it requires tools to apply sufficient pressure for a tight seal. To work around this problem, the regulating agencies revised the requirement to incorporate a hand wheel instead. 

With this new method, you do not need a wrench to achieve a tight leakproof seal, as it is designed with an O-ring.

In the past, POL fittings were the most popular propane tank connectors worldwide, including in the US. However, its popularity has decreased due to the introduction of new fittings in the market.

Overfill Prevention Device (OPD)

The US Department of Transport defines an OPD as a “backup safety shut-off device incorporated into a filling valve of a propane cylinder. It prevents cylinder overfilling in excess of the permitted maximum permitted filling limit”

Simply put, the OPD prevents overfilling a tank with propane for safety reasons. It is important to note the device is not used to measure the amount of gas filled into the cylinder. 

Rather, the OPD is another step in the precaution just in case that happens. The filling company should have other means to ensure the right amount of propane is filled into the tank. 

The OPD is a mandatory requirement by the DOT for all gas cylinders between 4 lbs and 40 lbs. Therefore, only gas cylinders with these propane tank connectors can be changed when refilling. You can distinguish gas cylinders installed with this device by its unique triangular handle wheel. This feature is unlike the traditional shut-off valve, whose shape is slightly different.

Another crucial feature is that an OPD is designed only to let in gas when attached to proper hoses leading to the appliances. The aim is to avoid the inadvertent opening of gas cylinders. Furthermore, it is connected to the valve stem, making it tamper-proof to protect users who may try to replace it.

So how does the OPD work? The device works with a float inside the gas cylinder, much like the floater in a toilet bowl. As the cylinder gets filled, the floater rises to the set level activating a lever that stops the flow of the propane into the cylinder.

Propane Tank Standards

Installing propane tanks requires you to follow specific safety regulations set by the National Fire Protection Association(NFPA 58) code. One of the foremost standard requirements is regarding the location of the tank on your property. Other considerations include certifications and specific fittings. 

All these standards can vary with the type and tank sizes. Below are the standard requirements for different propane tank categories.

Above Ground Tanks

The above-ground tanks are large-capacity tanks ranging from 100 to 500 and over 2000 gallons. The standard requirement is to have these tanks installed some inches above the ground and anchored on a cement platform or wood blocks. 

Additionally, you should only order them from certified and compliant sellers. Needless to say, there are things you should consider when choosing a propane delivery company. Others are standard propane connectors and fittings such as valves, regulators, and gauges.

As we mentioned above, location is a standard regulation. In most jurisdictions, home-use propane tanks require installation at least 10 Ft to 25 ft away from any property line or electrical device.

Underground Tanks

These types of tanks are similar to the above-ground tanks, although sometimes slightly larger. Underground tanks can hold approximately 250 to 2000 gallons of propane. Their standards for manufacturing and installation are almost similar to those required for above-ground tanks.

They have one difference, though; they should be buried underground. That is why they are considered less risky. Consequently, you can install it closer to the house than the above-ground tanks.
The standard depth of burying the tank varies with the tank size, but an average of 1-2 feet deep is an acceptable minimum.  As for the propane tank connectors, the standards are not different for the above-ground tanks.

Vertical Tanks

The vertical tanks are usually smaller than the other two we discussed above. Usually, they are less than 125 gallons. They are also considered less risky hence installation requirements are less stringent. But basic requirements such as having them outdoors or in an area with sufficient ventilation still stand.

Moreover, they have minimal propane tank connectors compared to larger tanks. For instance, they do not require pressure gauges and advanced regulators.

Final Thoughts

Gas tanks have different parts for different functions. These propane tank parts include pressure regulators, valves, gauges, and other fittings. Knowing their use goes a long way in enhancing safety and satisfaction in propane usage. Hopefully, this guide has equipped you with a better understanding of propane tank parts and their importance for a better user experience.

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Ryan McCabe

Ryan McCabe

Ryan is a home and small business energy expert, having overseen retail propane, heating oil, and HVAC services companies. On ComparePropane, Ryan writes about things that people should know when shopping for or using propane in their homes and businesses. 

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