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Sustainability in laboratories: fume hoods

“Shut the sash!” – a small act for change

2023/03/28

Even though laboratories occupy only a rather small fraction of TU Darmstadt’s space, they are still among the largest energy consumers of the University. But there is great potential to save energy!

The need to maintain proper exhaust air—an essential requirement along with constant laboratory conditions—results in an enormous electricity and heat demand. This is because the supply and exhaust air fans are not only working permanently, but the supply air needs to be pre-heated as well. A single laboratory fume hood needs 3.5 times the energy of an average family home. [1,2]

But there is hope: In addition to an optimised control of the technical systems by the Energy Management unit of TU Darmstadt, there is great potential for every operator to save large amounts of energy based on the way they use these fume hoods. This applies to both researchers in their laboratories and students during their lab practicals. By doing so, occupational safety and energy conservation go hand in hand!

The further you open the sash of modern fume hoods, the more air will be drawn in by the fume hood. Hence, the volume flow rate can be reduced by half if the sash is pulled down from its maximum working height to its closed position. [3] Consistently closing the sashes on the front and on the sides whenever the fume hood is not in use results in significant energy savings. This, of course, also has an impact on operating costs. A case study at two Californian universities showed that savings of USD 1300 from 2009 to 2011 per fume hood and year are possible simply by adapting the way fume hoods are used. [4] Another case study at Harvard (opens in new tab) indicates that this cost-saving potential can be tapped into through awareness campaigns, for example. [5]

Carlo Walz,
doctoral candidate in the field of chemical biology

In my opinion, it is nowhere as easy to save energy as in the laboratory and nowhere as important, too. Close fume hoods, turn off lab equipment no longer needed, separate waste – small effort, high impact, if everybody joins in.

Picture: privat

Hands-on

There are four essential aspects, you need to keep in mind to ensure optimal handling of fume hoods in terms of occupational safety and energy efficiency:

Whenever you are not working with your hands inside the fume hood, make sure that the sash is closed. Manually close the sash if you leave the fume hood even for short periods. This reduces the pre-set time for activating the automatic closing feature, if installed. You also need to make sure that moveable sash windows on the sides are completely closed because they do not close automatically even if the fume hood is a modern one. Their open position does not sound an alarm either.

Unless there is an explicit demand, do not increase the flow rate (vmax) manually. To save energy, it is worthwhile to check regularly that the flow rate has not been increased accidentally. Fume hoods that signal during normal operation that the air flow is too low must not be set to vmax permanently. Instead you are required to report this to Technical Operations using a digital form.

(To access this form, you need to log in using your TU ID.)

Unless there is an explicit demand, do not increase the flow rate (vmax) manually. To save energy, it is worthwhile to check regularly that the flow rate has not been increased accidentally. Fume hoods that signal during normal operation that the air flow is too low must not be set to vmax permanently. Instead you are required to report this to Technical Operations using a digital form.

On the page Störmeldung und Notruf (fault message and emergency call), this is done via a digital form stating Kälte / Lüftung (refrigeration / ventilation).

(To access this form, you need to log in using your TU ID.)

Fume hoods are most energy-efficient and safe if the air flow inside the fume hood is not disturbed needlessly. This is why fume hoods must be kept tidy and must not be used for storing chemicals or laboratory equipment, unless required by the experimental setup.

More advices

For more information on sustainability in laboratories, please refer to the webpage of the Department of Chemistry

Mehr erfahren

Sources

[1] Evan Mills, Dale Sartor (2005): Energy use and savings potential for laboratory fume hoods. In: Energy. Vol. 30, Issue 10: 1859-1864 https://www.sciencedirect.com/science/article/abs/pii/S0360544204004906

[2] Evan Mills, Dale Sartor (2006): Energy use and savings potential for laboratory fume hoods. https://energy.lbl.gov/publications/energy-use-and-savings-potential

[3] https://www.chemie.tu-darmstadt.de/fachbereich_chemie/organisation_chem/nachhaltigkeit_chem/nachhaltigkeit_chem.en.jsp

[4] Geoffrey C. Bell, Allen Doyle, Amorette Getty, Jesse Bickley (2012): Fume Hood Sash Stickers Increases Laboratory Safety and Efficiency at Minimal Cost: Success at two University of California Campuses. https://www.energy.gov/eere/femp/articles/fume-hood-sash-stickers-increases-laboratory-safety-and-efficiency-minimal-cost

[5] Quentin Gilly (2016): Validating cost and energy savings from Harvard’s Shut the Shash program. https://www.mygreenlab.org/uploads/2/1/9/4/21945752/fh_-_harvardfumehoodwhitepaper.pdf (opens in new tab)