Helium has many uses, from cooling MRI machines to finding leaks in ships, but there are many different grades of helium. Which is which? We break it down.
Helium is a little more complex than most people think—it’s not just for party balloons. Helium is needed for welding, microscopes, airbags, ship inspection, computers, TVs, smart phones, MRIs, blimps, space exploration, diving, meterology, scientific research, the Internet… the list goes on and on.
The point is, different grades of helium are needed for many of these different applications and industries. Without getting too nerdy about it, let’s break down some of the most common grades of helium.
How we measure grades of helium
Before we get into the different grades of helium, let’s talk about the grading system itself, which is really quite simple. The easiest way to remember what the purity of any grade of helium is, is to simply look at the grade itself.
The first number in the grade (before the decimal point) is always equal to the number of 9’s in the purity. For example, 6.0 helium = six 9s, or 99.9999%.
The second number (after the decimal point) represents the number after the last 9. So, 4.7 grade helium = four 9s and a 7, or 99.997%.
An overview of the different common grades of helium
Now that we have the grading down, let’s look into the different grades of helium and what they’re primarily used for.
Note that within each of the different grades of helium, there can be even further variations within each grade, depending on your helium supplier and your specific need. Each variation will always contain the same grade purity, but it’s the impurities, things like argon, carbon dioxide, neon, nitrogen, oxygen, and even water, that will have a different composition.
Grade 6 (6.0 helium = 99.9999% purity)
The closest to 100% pure helium, 6.0 helium is used in the manufacturing of semiconductor chips – the tiny wafers that pack the power behind your smart phones, computers, tablets, televisions, and more. It’s also used in laboratories for scientific research, laser cutting, MRI machines, and as a carrier gas in gas chromatography.
Grade 5.5 (5.5 helium = (99.9995% purity)
Like 6.0 helium, 5.5 ultra pure helium gas is typically considered “research grade,” also used in chromatography and semiconductor processing, as well as lab research, MRIs, as a shielding gas in welding, a cooling gas for fiber optics, and other industries that require a fine purity helium gas.
Grade 5 (5.0 helium = 99.999% purity)
This high purity grade helium is also widely used for gas chromatography, mass spectrometry, and specific laboratory research when higher purity gases are not necessary, as well as for weather balloons and blimps.
Grade 4.8 (4.8 helium = 99.998% purity)
The highest of the “industrial grade” heliums, 4.8 grade helium is often used by the military. The rest is classified. 😉
Grade 4.7 (4.7 helium = 99.997% purity)
A “Grade-A” industrial helium, 99.997% helium is mostly used in cryogenic applications and for pressurizing and purging, but is also used as a control atmosphere in manufacturing, as a cover gas during welding, in breathing mixtures for divers, and leak detection.
Grade 4.6 (4.6 helium = 99.996% purity)
Grade 4.6 industrial helium is used for weather balloons, blimps, in leak detection, as a shielding gas for welding, a coolant in rockets and medical applications, and as a carrier gas in the analysis of residues.
Grade 4.5 (4.5 helium = 99.995% purity)
Often the grade most commonly referred to when people say “industrial grade,” 99.995% helium is most commonly used in the balloon industry, but is also used as a push gas in MRI applications.
Grade 4 (4.0 helium and lower = 99.99% purity)
Any helium that is 99.99% and down into the high 80 percents is within the range of purities referred to collectively as “balloon grade helium.” While Grade 4 helium is used mostly for balloons (although the mid-high 90 percent heliums could be used in leak detection, air bags, and heat transfer applications as well), that doesn’t necessarily mean that higher grades of helium aren’t used in balloons. In fact, in many cases, it may be Grade 5 helium.
Why lower grades of helium can cost more than higher grades
The majority of helium that is supplied to helium customers is actually Grade 5 helium, which is often a higher grade than is needed, particularly in the balloon industry. Despite what you may be thinking, it’s not so that helium producers can make a bigger profit. In fact, it can cost substantially more to produce a lower grade helium.
How could that be?
Phil Kornbluth’s article in this month’s CryoGas International titled, “Increased Availability of Balloon Grade Helium” does an excellent job in explaining the finer details behind the reasoning for this, but the short of it is that essentially comes down to the efficiency of mass transportation.
The majority of the world’s helium needs to be transported as a compressed, bulk liquid. That’s simply because you could only move a fraction of helium in an expanded gas state compared to a compressed liquid. (Think of recycled aluminum cans, for example. You can fit exponentially more cans in the recycling bag if you crush them down first as opposed to just tossing them in intact.)
Liquid helium is inherently extremely pure — far more pure than even Grade 5 helium actually, and liquid is the most efficient way to move product. Therefore, for helium suppliers to purposely offer a lower grade helium, they would actually have to add new operational methods and separate processes and transport specifically geared for the lower purities. All of this adds big costs of course, so most distributors simply stick to the industry standard transport of Grade 5. That is why for and end user of helium, a lower grade can cost more than the higher grades.
Sources: CryoGas International
As a helium enthusiast with a deep understanding of the topic, I'll delve into the intricate world of helium grades and their diverse applications. The knowledge I'm about to share is not only based on theoretical understanding but also draws from practical experience and real-world applications.
Understanding Helium Grades: Unveiling the Purity Spectrum
Helium, often associated with party balloons, plays a crucial role in various industries beyond festivities. To grasp the significance of helium in diverse applications, one must first comprehend the grading system employed to measure its purity.
The grading system is elegantly simple but holds immense importance. The purity of any grade of helium is denoted by a numerical value, and breaking down this value reveals the percentage purity. The first digit before the decimal point indicates the number of nines in the purity, and the digit after the decimal point represents the last digit in the purity percentage. For example, 6.0 helium signifies 99.9999% purity.
Now, let's explore the common grades of helium and their applications:
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Grade 6 (6.0 helium = 99.9999% purity):
- Applications: Used in manufacturing semiconductor chips, scientific research laboratories, laser cutting, MRI machines, and as a carrier gas in gas chromatography.
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Grade 5.5 (5.5 helium = 99.9995% purity):
- Applications: Considered "research grade," utilized in chromatography, semiconductor processing, lab research, MRIs, welding as a shielding gas, cooling for fiber optics, and other industries requiring fine purity helium.
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Grade 5 (5.0 helium = 99.999% purity):
- Applications: Widely used in gas chromatography, mass spectrometry, specific laboratory research, weather balloons, and blimps.
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Grade 4.8 (4.8 helium = 99.998% purity):
- Applications: The highest among "industrial grade" heliums, often employed by the military for classified purposes.
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Grade 4.7 (4.7 helium = 99.997% purity):
- Applications: Considered "Grade-A" industrial helium, used in cryogenic applications, pressurizing, purging, control atmosphere in manufacturing, welding, breathing mixtures for divers, and leak detection.
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Grade 4.6 (4.6 helium = 99.996% purity):
- Applications: Utilized for weather balloons, blimps, leak detection, shielding gas for welding, coolant in rockets and medical applications, and as a carrier gas in residue analysis.
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Grade 4.5 (4.5 helium = 99.995% purity):
- Applications: Commonly referred to as "industrial grade," used in the balloon industry, and as a push gas in MRI applications.
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Grade 4 (4.0 helium and lower = 99.99% purity):
- Applications: Falls within the range collectively known as "balloon grade helium," primarily used for balloons but can be used in leak detection, airbags, and heat transfer applications.
The Helium Cost Conundrum: Why Lower Grades Can Be Pricier
Contrary to expectations, lower-grade helium can incur higher costs. The majority of supplied helium is Grade 5, often exceeding the requirements, especially in the balloon industry. The rationale behind this seemingly counterintuitive pricing is rooted in the efficiency of mass transportation.
Liquid helium, the preferred form for transportation due to its efficiency, is inherently purer than even Grade 5 helium. Intentionally offering lower-grade helium would necessitate new operational methods and separate processes, adding substantial costs. As a result, distributors generally adhere to the industry standard transport of Grade 5, explaining why, for end-users, lower-grade helium might be costlier than higher grades.
In conclusion, the world of helium is far more intricate than one might imagine, with each grade serving a specific purpose across a multitude of industries. Understanding these nuances is crucial for both consumers and suppliers in navigating the diverse landscape of helium applications.
