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Pattern of Flow

Tue, 02/26/2013 - 4:23pm
Paul Livingstone

As the laboratory construction industry struggles to recover, fume hood manufacturers jockey for better positions and products.

Launched about four years ago, AirClean’s Independence ductless filtering hood was outfitted as a top-tier fume hood with an onboard chemical library and advanced detection tools. Fume hood manufacturer Kewaunee has recently partnered with AirClean to launch its own filtering fume hood at the 2013 Pittcon Conference. Image: AirClean SystemsFive years behind us, the latest global recession's impact carried shockwaves that continue to affect the research laboratory industry. During the recession, manufacturing numbers plunged, along with the prognosis of positive growth for a variety of industries, including industrial research.

The downturn was unwelcome news for the fume hood industry, which, in the beginning of the year, anticipated times of stronger growth. R&D spending, closely tied to corporate revenue, dropped significantly in 2008 following the housing market crash. Less capital for new equipment meant a weaker overall outlook for laboratory outfitters. However, a turnaround may finally be happening, and general pent-up demand gives vendors a chance to put some of their newer high-performance hoods in front of researchers in 2013.

Development accelerates despite recession
In anticipation of recovery, fume hood manufacturers have generally improved their efforts to create new products. Competition for a more limited field of U.S. customers has encouraged creativity among vendors. A variety of innovative technologies have been integrated into the latest high-performance fume hoods—both traditional and ductless filtered—to deliver on a few key selling points: ease of use, energy use, and flexibility.

Safety is still the core mission of any fume hood company, but fume hoods are not strictly regulated in their basic function, which is to contain toxic gases within an enclosed space and prevent contamination of the air respired by a user. They must provide and sustain containment, and a variety of testing practices exist to help designers determine the best design for their product given its intended usage. The standard set of testing procedures to achieve this equivalency has been delineated by the American Society of Heating, Refrigerating, and Air Conditioning Engineers (ASHRAE) and is generally updated every few years. A rewrite of the accepted 1995 standard was completed in 2005.

The "Z9" test, published by the American National Standards Institute (ANSI) and recently updated in 2011, provides additional testing protocols to ensure overall laboratory air quality, not just air at the fume hood. And most vendors also look to the recommended practice guidelines offered by the Scientific Equipment and Furniture Association, Garden City, N.Y., which published a guide specifically for fume hoods, last updated in 2010.

The Occupational Safety and Health Administration (OSHA) does not have specific requirements for fume hood face velocity, giving fume hood vendors room to explore designs that feature reduced face velocity rates, yet maintain containment. However, concerns about safety have meant that many manufacturers of traditional hoods have proceeded cautiously in making changes to their product line. Many organizations for laboratory design practices continue to recommend face velocities of 80 to 120 feet per minute (fpm) to help guarantee containment to ensure safety in the use of a variety of toxic chemicals.

Numerous vendors offer low-flow and high-performance fume hoods that consume less outside air and deliver a face velocity as little as 55 fpm. But they also continue to offer traditional full-flow fume hoods, which tend to be a less expensive initial investment.

But few fume hood users require the absolute maximum of air volume for contamination.

Specific tasks require specific chemicals, and only a few cannot be handled by the cost-conscious alternative to traditional fume hoods: the ductless filtered hood. More compelling, however, is the tremendous cost incurred by laboratories that operate a large number of fume hoods.

Shrinking laboratory budgets have forced managers to adopt lean measures in laboratory operation. Energy use is a leading expenditure for research operations, and fume hoods are a famously large contributor to this expense: A single fume hood can use more than 20,000 kWh per year. Low-flow or variable air volume (VAV) fume hoods can lower that rate by as much as 40 to 50%, saving several thousands of dollars in electricity costs over the course of several years. The rising expense of energy has forced traditional fume hood makers to innovate.

Traditional fume hood makers adapt
More than 100 years old, Kewaunee Scientific Corp., based in Statesville, N.C., is known for its technical furniture products, including casework, safety cabinets, and sinks made from a variety of durable materials. They are also well known as a manufacturer of traditional ducted fume hoods.

Labconco Corp.’s most advanced line of high-performance fume hoods, the XStream, is able to maintain fume containment at face velocities of as little as 40 fpm. Computer modeling and sophisticated testing procedures have allowed traditional fume hoods to conserve air use and energy while maintaining safety. Image: Labconco Corp.Not immune to change, Kewaunee has invested heavily in its fume hood technology. One of its biggest breakthroughs in recent years has been the low-flow Supreme LV fume hood, which, despite a face velocity of just 55 fpm, performed to the company’s satisfaction when tested under the ASHRAE 110 method. The ASHRAE standard has sections for visualization of flow patterns, measuring face velocity, and measuring containment using a tracer gas. This hood, which is more expensive than Kewaunee’s standard Supreme line, helps cut energy use by up to 45%. It also provides users the flexibility of the older hoods thanks to a configurable sash and variable airflow (constant volume).

Another unique feature of the LV hood is that the sash automatically lowers to the operating height of 18 inches. On constant volume hoods, this raises the capture velocity from 55 to 84 fpm. This hood was tested with external air disturbances, such as a walk-by test, and with user arm movements within the hood. It is designed to perform at 55 fpm as good or better than traditional hoods operating at 100 fpm.

"Four years ago, these low-flow, high-performance hoods were a trending development. These technologies are more mature now. We've sold a lot of low-flow, high-performance hoods," says Kurt Rindoks, vice president of engineering at Kewaunee. "Extending that idea further, fume hood makers are installing more complex components such as auto-sash closures which, when integrated with VAV systems, have managed things even better for users."

Now, customers are forced to have proper management of sash operation, says Rindoks. "With our sash closures, the researcher doesn't have to remember to close the sash—it does it for them."

Kewaunee's major focus when developing these technologies was to guarantee flexible usage.

The auto-sash has no usage restrictions in the left or right direction, and access depends mainly on the vertical sash position. When combined with VAV technology that automatically adjusts flow to match the position of the sash, the researcher can conduct their work without constantly monitoring sash performance. The Supreme LV has been a strong seller in the new construction sector, says Dana Dahlgren, Kewaunee's vice president of sales and marketing, because it is well-suited for new, highly controlled environments that monitor air quality and laboratory air exchange rates.

The big news for Kewaunee, however, is the imminent arrival of a new line of ductless filtered hoods, the DetectAir line, that incorporates the advanced baffle, airfoil, and bypass technologies developed from the Supreme LV hoods with the air detection and filtration system developed by AirClean Systems, of Raleigh, N.C. This joint venture will be announced at Pittcon 2013 in Philadelphia on March 17-23. The move has been prompted by Kewaunee's recognition of the advantages and drawbacks of current ductless filtering hood technologies.

"We partnered with AirClean, utilizing their electronics technology and some of their ventilation technology. What we’ve done is marry these two technologies," says Rindoks.

The partnership makes sense for several reasons. First, the two companies tend to serve different markets and different types of customers. Kewaunee has never offered a ductless filtered hood, and has traditionally been resistant to the idea. They needed expertise in filtration design, says Howell, which AirClean offers. They also have proximity; the two companies are just a few miles from each other.

"Basically it's our 20 years of knowledge in filtration" that they needed, says Brandon Howell, vice president and technical director of AirClean. "Kewaunee can certainly design a hood, but they’ve never jumped into the filtration arena. Our partnership works because we don’t cross over too much in the market," says Howell.

Another leading fume hood manufacturer, Labconco Corp., Kansas City, already has a line of ductless filtering hoods, called the Paramount. However, Labconco’s focus has always been on refining and improving its chemical fume hoods; and in the past decade, the company's portfolio has expanded to include a line of high-performance hoods. The XStream, the most advanced of the three, features a bypass airflow design with VAV compatibility; heavily optimized designs for baffles, air foils, and sash handle; and a blowerless system for delivering dilution air in the upper portion of the hood.

Using computational fluid dynamics tools, Labconco engineers created an enclosure that produces horizontal airflow, which reduces the tendencies for turbulence. The sash handle, air foil, upper dilution air supply, and rear downflow baffle work together to create patterns of flow that reduce concentrations of chemical contaminants throughout the work area, particularly near the operator's breathing zone and at the surface. Depending on sash position, tendencies for air turbulence, or vortexing, are eliminated.

According to Luke Savage, sales engineer and fume hood product manager at Labconco, XStream may one day become the baseline fume hood. The industry, he says, is heading in the direction of high performance.

"The chemical fume hood has historically been a very large consumer of energy, so look for more technology related to solving the issue of energy consumption, or at least reducing the energy consumption of a chemical fume hood," says Savage.

Until recently, Savage says, too many measures to reduce energy use and the consumption of tempered laboratory air in fume hoods have compromised either comfort or safety. Now, a variety of tools are helping companies like Labconco improve their products without cutting into the safety of the fume hood. Early on, mechanical system controls helped advance the efficiency of VAV hoods, but embedded computational aids are now automating functions like sash position. Labconco has also developed technology which specifies the deviation of face velocity air beyond a certain pre-selected point. The face velocity profile can then be optimized, through sash position and airflow configuration, based on this profile.

"We're putting a larger portion of the fume hood’s required air volume to work than has been done since the bypass fume hood was developed," says Savage. As a consequence, the total air rate of the fume hood has been reduced significantly, regardless of the desired face velocity.

"Then when you add those mechanical control systems, you get a compounding of your reduction in energy use," says Savage.

He offers an example. A typical 6-foot fume hood operating at 100 fpm has a typical air rate of 1,250 cfm. After a thorough assessment of conditions and hood design required to maintain containment, the hood can be engineered to consume 11 cfm and still maintain 100 fpm containment.

"And that's not deviating from the 100 fpm face velocity. It's also based on a 15-year fume hood lifespan. Some [hoods] will last longer than that," says Savage. A reduction in face velocity to 60 fpm, when using a low-flow hood, can drop air use by 90%, potentially netting tens of thousands of dollars per year in energy savings for a single hood.

This image shows a large installation of 6-foot-wide Labconco fume hoods in a laboratory at Meredith College in North Carolina. After several years of slow or stagnant growth, fume hood manufacturers are counting on pent-up demand for advanced, energy-efficient fume hoods to accelerate sales. Image: Labconco Corp.Growth of filtered fume hoods
When R&D Magazine last reported on the fume hood industry, ductless filtering fume hood manufacturers were making a big marketing push in the U.S. AirClean has manufactured fume hoods since 1992, but in 2008 its technology advanced significantly when it launched a fume hood, the Independence, that featured Silconazyne bonded filtration.

This gas phase filtration system is a chemically and thermally enhanced filtration technology that features silica bonded in a matrix with high-surface-area carbon. This higher-capacity solution, when united with gas analyzers, filter monitoring, and an onboard chemical library, allows the Independence to work with 99% of the chemicals AirClean carries in its database. This type of filter architecture, while unique in its construction for AirClean, operates on a similar principle when applied by other manufacturers, including Erlab and Mystaire Misonix, Creedmore, N.C. Traditional vented hoods, which rely on a laboratory's internal air-exchange infrastructure to prevent inhalation of toxic gases, are the industry standard and remain in use at most laboratories. However, the ductless hood has been eyed as a possible partner to the traditional hood for two big reasons. First, it's far less expensive to operate. While filters need to be changed on a regular basis, energy consumption is minimal compared to a high-exchange hood.

The second reason is its popularity in Europe, which has been purchasing ductless hoods made by Erlab, Rowley, Mass., since 1968. Europe pays a much higher cost per capita for its energy, and researchers there have had to adapt to ductless and ductless filtering fume hoods for many years. Erlab’s filtration technology relies on the Neutrodyne product, which offers a broad spectrum of use in a single filter. The company’s most recent major innovation, Neutrodine 2G, represents a significant improvement in the capacity and filter lifetime of the Greenfumehood. It is made of three layers working under the principle of low aeraulic pressure reaction, with an additional carbon layer, and has been tested under AFNOR NF X 15-211 guidelines for ductless filtering hoods established by Union de Normalisation de la Mécanique in France.

Erlab's general manager, Stephane Hauville, believes a number of factors—not just filtration technology—are giving ductless filtering hoods a big opportunity to grow in the U.S. marketplace.

"A ductless system alone is only able to detect specific chemicals, and not in real time, and not all the time. A filtered hood can detect a multitude of different chemicals in real time," says Hauville. "It's also a communications device, one that explains and identifies issues with containment or issues with fire."

In 2008, Erlab began selling the Neutrodine technology in the U.S. under the name Greenfumehoods. The Greenfumehoods differ in scope from Erlab's traditional Captair line of ductless hoods. In addition to the Neutrodyne filtration technology, the company invested heavily to improve the hood's flexibility and ability to be used in a wide variety of industrial applications. The hood’s modular filtration column allows users to stack activated carbon filters, fans, lights, and HEPA filters in a way that optimizes the hood for research using solvents, or research in a cleanroom. The setup is known as a "revolving filter" because it places a chamber containing a molecular detection system between two filters with identical capacities. When the main filter is saturated, excess molecules are directed toward an identical safety filter placed directly above. This prevents toxic molecules from escaping. Eventually, the safety filter is moved down to take the place of spent main filter.

On the communications side, Greenfumehoods can be monitored, accessed, and controlled remotely using a computer or smartphone. The monitoring system, called g-Guard, can issue alerts from a number of different hoods, and with an internal communication protocol called Bacnet, up to 250 hoods can be controlled together.

Hauville says that by communicating the status of hoods to the laboratory manager, who can see this information on a computer dashboard or smartphone, a more efficient and secure laboratory can be achieved. This, he says, helps build trust for the product.

A shake up in the industry
In October 2012, the laboratory furniture industry was rocked by an unexpected announcement. A Los Angeles private investment firm, OpenGate Capital, bought the entire Laboratory Workstations business of Thermo Fisher Scientific Inc. The company became Hamilton Scientific Inc. The price was undisclosed, but with 1,800 employees, $175 million in revenue, and three fume hood brands—Hamilton, Advanced Laboratory Concepts, and Collegedale—the company is a major player in the fume hood industry.

The effects of this move remain to be seen, but other fume hoods manufacturers see it as an opportunity to grow their brands.

"I think it will probably help almost everyone else in the industry because they were the biggest," says Kewaunee's Dahlgren. A moribund economy has stifled fume hood purchases in recent years, and the smaller fume hood companies are looking forward to growth. "I do see that there has been some pent-up demand over the last few recessionary years," he adds.

At Labconco, Savage also has a positive outlook on this industry. He points to improvements in safety and efficiency as core drivers for growth. When the push for efficiency began, he says, safety strategies suffered. That picture is changing as a better understanding of airflow has improved products.

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