A fume hood is an essential piece of equipment found in almost all laboratories, from teaching labs to research labs to industrial labs. The fume hood limits exposure to hazardous or noxious fumes, vapors or dusts by safely removing these substances from the immediate working environment. The fume hood also serves to protect the sample from the external environment.
Fume hoods may either be ducted or recirculating. Both types operate by allowing air to be drawn in from the front (open) side of the cabinet, and either expelled outside the building or made safe through filtration and recirculated back into the room.
The history of fume hoods can be traced back to the days when Thomas Edison used his fireplace chimney to exhaust fumes from his laboratory.
Early twentieth century – the origins of fume hoods
Working in around 1900, Thomas Edison seems to have been one of the first scientists to be concerned about laboratory ventilation. Edison used the fireplace chimney in his lab to exhaust noxious fumes and odors from his experiments into heated rubber compounds, using the natural draft of the chimney to expel the gases.
In 1923, one of the first recognizable fume hoods in the modern sense of the word was in use at the University of Leeds. This unit consisted of a large cupboard standing at working height and incorporating vertical rising sashes arranged like parallel windows.
In 1936, Labconco, one of the pioneering manufacturers of fume hoods, developed its first fume hood for sale commercially. This unit incorporated the now-familiar sash fronted design, allowing a single operator to work safely by placing his hands within the "cabinet."
World War II
Considerable advances in fume hood technology were made during the second world war in response to the fear of exposure to highly toxic chemicals and radioactive materials. Against this catastrophic backdrop, significant progress in safety, ventilation, and fume hood design was made.
Also during the war years, the high-efficiency particulate air (HEPA) filter was developed by the body which later became the Atomic Energy Commission. The development of the HEPA filter had a dramatic effect on the effectiveness of fume hoods and biological safety cabinets, greatly increasing protection for users.
In 1943, John Weber, Jr. working at the Ames Laboratory in Ames, Iowa, developed the concept of a constant face velocity, variable exhaust flow fume hood control. This design was applied to a vertical rising sash hood served by a dedicated hood exhaust fan. The concept eventually became a standard feature employed on many fume hoods at that time in atomic laboratories, especially where ventilation containment within the hood was critical.
In the early 1950s, John Turner, working in the Engineering Department at Oak Ridge National Laboratory (ORNL), suggested replacing vertical rising sashes with horizontal sliding sashes in order to reduce energy consumption. He also introduced the use of a mechanical damper that worked off the imbalance between external and internal hood pressures.
Around the same time, Weber also recognized that best containment in a fume hood was achieved with minimum sash opening when he developed the emergency quick close feature incorporated as a part of his system. The exhaust fans used as a part of Weber's system were never turned off.
In 1951, H.W. Alyea, Chief Field Engineer, Johnson Service Co. (now Johnson Controls, Inc.), realized that keeping the door of a fume hood closed as much as possible, and certainly when not in use, resulted in considerable savings in the amount of air supplied, with proportional reduction in cooling demand, improved filter life, and considerable energy savings.
In 1961, Labconco introduced its first one-piece molded fiberglass-line fume hood, the Fiberglass 47. Fiberglass was chosen to line the fume hood as it offers durability, cleanability, high-light reflectivity, fire resistance and chemical resistance. The one-piece, fiberglass liner has been a signature feature of Labcono’s general chemistry fume hoods since this time.
Labconco’s Fiberglass 28 fume hood, introduced in 1965.
In 1968, Francois-Pierre Hauville created the company Erlab and began selling the first Captair ductless fume hood in the same year. Erlab continues to develop and market the Captair range of fume hoods today.
The greatest innovation enjoyed during the 1970s was the development of auxiliary air fume hoods, which conserved energy by introducing outside air into the hood, reducing the loss of tempered air from the laboratory. This type of fume hood requires the use of two duct and blower systems.
During the 1970s, Labconco developed the fiberglass walk-in fume hood, allowing the researcher more room to operate, and enabling work with larger pieces of apparatus in a safe environment. Walk-in fume hoods are a common feature in many laboratories today.
An important milestone achieved during the 1990s was the development of the sash-limiting device designed to limit the amount the sash could open without hindering access, and reduce the energy consumption of the fume hood.
In 1996, the AFNOR AF X 15 211:1995 standard was introduced, allowing the performance of a ductless fume hood to be evaluated based on strict criteria. This standard is used today as the reference standard for all fume hoods.
In 1997, Lab Crafters introduced their patented, high-performance Air Sentry fume hood, the first high-performance fume hood to be introduced to the market. This fume hood offered an efficient and quiet operation designed to operate in the ‘real world’ conditions of cross-drafts and temperature and pressure fluctuations, for example. More than 1200 Air Sentry fume hoods are currently installed across the country.
In 1998, Erlab expanded its Captair product range to meet the demands of the modern laboratory. New instruments included the CaptairStore (a vented filtering storage cabinet), the CaptairBio (a PCR workstation), and the CaptairFlow (incorporating HEPA-filtered enclosures).
One important milestone to occur during the 2000s was the development of low-flow fume hoods operating at 50-60 fpm. These instruments allowed considerable cost and energy savings, while still delivering the performance of earlier models.
In 2005, Flores Valles introduced Adiprol, a new fume hood providing high chemical resistance and a total fire proof property designed specifically for use in schools and universities.
Flores Valles’ Adriprol fume hood for use in schools and universities.
In 2007, Lab Crafters introduced the Air-Prentice fume hood, a variation of the Air Sentry fume hood specifically designed for academic science laboratories. This fume hood was designed to offer excellent performance at a price appropriate for academia.
Lab Crafters Air-Prentice
In 2008, Erlab presented their new Greenfumehood technology for the first time at Pittcon. Greenfumehood technology marked a new generation of fume hoods designed primarily to be safe, energy-efficient, cost effective and environmentally friendly.
In 2009, Thermo Fisher Scientific launched its own energy-efficient fume hoods, the Hamilton Infinity fume hoods. These fume hoods incorporated an AutoSash feature designed to maximize laboratory safety by ensuring correct sash positioning with an extra trough positioned at the front of the unit to catch any spills.
Thermo Fisher Scientific’s Hamilton Infinity fume hood.
Also in 2009, AirClean Systems began selling the Independence ductless fume hood. This device incorporated a Silconazne filtration system that offered advances in gas phase filtration, filtration monitoring, airflow control and monitoring, and user-friendly operator interaction to make the unit one of the safest in the world.
Air Clean Systems’ Independence ductless fume hood.
In 2010, Air Science introduced a new series of Enhanced Filtration Technology (EFT) carbon filters for use in the company’s line of ductless fume hoods. Enhanced Filtration Technology was a universal filtration system developed for use with a wide range of core chemicals including organic acids, alcohols, aliphatic hydrocarbons, aromatic hydrocarbons, esters, aldehydes, ketones, ethers, halogens, as well as inorganic acids.
In the same year, Air Science also introduced the Purair ECO line of energy-saving ductless fume hoods designed for both chemical and particulate protection over a broad range of laboratory and industrial applications and based on the use of EFT filters. The Purair ECO was developed in response to an increasing worldwide demand for safe, cost-effective and energy-efficient ductless containment cabinets that minimize stress on facility HVAC systems without compromising protection for personnel and the environment.
The Purair ECO energy-efficient ductless fume hood.
In 2011, Air Science introduced the mobile ductless fume hood providing all-around visibility for classroom demonstrations and industrial training. The unit was designed to be self-contained and easily moved from laboratory to laboratory.
Air Science mobile ductless fume hood
Future of fume hoods
The driving force behind further innovation in the field of fume hoods in the near future is likely to be the demand for increased energy efficiency and reduced running costs. High-performance fume hoods promising a reduced environmental impact are likely to become standard, and further advances are likely to be based around fume hoods offering low-flow performance and smart mechanical systems.