A Guarantee of Purity

Defining the term “specialty gas” seems simple at first. But after considering the numerous ways specialty gases might differ from their commodity counterparts, it becomes tempting to apply the aphorism “I can’t define it, but I know it when I see it.”

Bob Jefferys, marketing communications director for Air Liquide America Specialty Gases (Plumsteadville, PA), applies what is arguably the number one differentiator. “Specialty gases are very high-purity products consisting of single gases, up to mixtures of fifty or more individual components,” says Jefferys. “And they tend to be a lot more expensive than run-of-the-mill industrial gases.” For example, high-purity helium is employed as the mobile phase for gas chromatography. “It’s not the same product you’d use to inflate helium balloons at a birthday party,” Jefferys says.

“The definition of ‘specialty gas’ comes up at every training session I conduct,” says Todd Morris, director of laboratory markets at Airgas (Radnor, PA). “The basic definition I use is ‘any gas that’s tested for purity after the cylinder is filled.’ That can include pure gases like nitrogen, oxygen, and argon, or custom gas blends.”

All major ga MANUFACTURERS provide specialty pure gases in several grades, ranging from high purity (99.998% min. purity) to ultra-high purity (99.999% min. purity) to research grade (99.9999% min. purity). Each grade is tested for a defined set of impurities, such as levels of oxygen, moisture, total hydrocarbons, carbon monoxide, nitrogen, and others.

Like commodity gases, specialties are distributed under an unusual economic model: Customers purchase the gas and rent the container (usually a steel or aluminum high-pressure cylinder fitted with a heavy-duty valve). Depending on the size of the container and the type of gas, the costs can run from $100 to as much as $3,000. Rental, or “demurrage,” typically amounts to less than a dollar per day per cylinder. While not expensive for a single tank, costs can add up quickly for large companies with hundreds of cylinders. Because gases are often deployed at the laboratory or individual level, large organizations have difficulty keeping track of which cylinders are empty or are no longer in service. Best-in-class specialty gas companies send out periodic email messages or other reminders for customers to check their gas inventories.

Two main factors enter into specialty gas purchase decisions: price and quality. For gases, “quality” means some desirable combination of purity and mixture accuracy. For each end use, the grade required is entirely customer-driven. “The first thing we ask when a customer specifies a pure gas is which impurities will adversely affect their application,” notes Morris. “Once that is understood, it is relatively straightforward to set the customer up with the appropriate gas.”

The specialty gas business has become more competitive during the past decade, with many smaller businesses being acquired by large manufacturers. At the same time, end users have become more demanding in terms of specialty gas purity and composition. Keeping up with the marketplace involves staying abreast of gas analysis and blending techniques. “A major supplier should maintain a high degree of technical expertise,” Jefferys says, “in order to retain its customers.”

Specialty Gas Regulators

• Made from solid bar stock with a needle valve built in the regulator body to reduce internal volume
• Feature stainless steel diaphragms for consistent, high-purity results
• Check-valve cylinder connection option prevents contaminants from entering gas stream during cylinder change out

Airgas
www.airgas.com

Perma-Cyl Gas Vessel

• Allows liquid to be held for long periods of time without venting, limiting product loss
• Auto shut-off feature allows remote filling with wall box and piping
• Constructed of stainless steel
• Features a Cyl Tel gauge on 450-, 1,000-, and 1,500-liter models

Middlesex Gases & Technologies
www.middlesexgases.com

NitroVap-1LV and NitroVap-2LV

• Produce more than 320 LPM of pure evaporation grade nitrogen
• Require less than 1 square foot of bench space and can supply more than 100 evaporator nozzle positions
• Use a combination of filtration and membrane separation technologies
• High-efficiency coalescing filters remove all contaminants down to 0.01 micron

Parker Balston
www.labgasgenerators.com

ALPHAGAZ™ Series

• Available in three grades and two purity ranges
• ALPHAGAZ 2 exhibits the absolute lowest impurity levels available in the industry
• ALPHAGAZ 1 exceeds purity recommendation of most laboratory instrument manufacturers, making it suitable for general lab use

Air Liquide
www.alspecialtygases.com