Fume hoods at UBC consume up to 10 per cent of campus energy due to the large volume of air that needs to be heated or cooled and moved through the hoods.
Read our FAQs below to learn more about the Shut the Sash competition and why shutting the sash makes a difference.
What is Shut the Sash?
A six-week competition to save energy through one simple action—closing laboratory fume hoods.
When & where WAS the competition?
The 2020 competition from November 3 to December 13 was held in Chemistry Buildings D and E.
What were the results?
The results are in! We saw an approximate 7 percent reduction in volume of air flow relative to pre-campaign data, translating into important energy and cost savings. Indeed, if this behaviour can be kept up it would mean yearly energy cost savings of $3500 in Chemistry D and E alone! A huge thank you and congratulations to the folks in Chemistry D and E buildings for your efforts to conserve energy and shut the sash! A special congratulations to our two winning groups, Orvig and Fryzuk.
Interested to start a competition in your department? Contact us at Green.Labs@ubc.ca
Learn about other energy conservation opportunities in labs.
What were the prizes, and who won?
A prize of $100 each was awarded to the two winning lab groups to celebrate their success:
- Most Improved: The lab with the biggest improvement in sash best practices during the competition compared to baseline won this prize. The winning group was: Fryzuk
- Lowest average sash height: The lab that achieved the lowest average exhaust rates over the competition period. The winning group was: Orvig
How were the winners determined?
Over the last year Green Labs tracked fume hoods through the building management system (BMS) to establish baseline use patterns.* Specifically, we looked at the exhaust rate for each fume hood which changes in proportion to the height of the sash. In other words, the lower the sash, the less air that is exhausted. We continued to collect this data throughout the competition and compared it to baseline patterns.
Lab fume hood use summaries and ranking were shared periodically for each lab.*
* While use patterns and tracking are available in a lot of our lab spaces through the BMS, not all spaces and fume hoods have measurable data points and systems. Additionally, due to HVAC mechanical system designs not all fume hood exhaust systems save energy when the sash is closed. However, it is still safer to keep the sash closed when not working in the hood. Closing the sash promotes safe and sustainable practices to carry with you to new lab environments.
Fume hood and energy FAQs
Why do fume hoods use so much energy?
An open fume hood uses as much energy as 3.5 homes! Well, it’s not the fume hood itself, it’s the air being sucked through it.
For health and safety reasons, labs use 100 per cent outside air. That entire volume of air first has to be heated with steam (i.e. natural gas) or cooled by a chiller (i.e. electricity) to make it a comfortable temperature before it is brought into the lab. A lot of electricity is also required to run large supply and exhaust fans that move the air through the building and through the fume hoods.
How does shutting the sash save energy?
Variable air volume (VAV) fume hoods are designed to maintain a constant face velocity across the sash opening. Sash position is connected to the building’s HVAC system so that the fan speed and the volume of air are reduced when the sash is lowered.
VAV fume hoods are mostly found in newer labs at UBC that have been recently constructed or renovated. While typically only labs with VAV fume hoods have been invited to participate in Shut the Sash, it’s best practice for all fume hood users to lower the sash when not in use and promote safe and sustainable lab practices.
Is it safe to shut the sash?
The sash is an important safety barrier between the fume hood interior and the laboratory, protecting the lab user. Sashes should be opened only to set up or modify an experiment. At all other times, shutting the sash is safest. When the sash is shut there is still some air flow through the hood to remove any fumes.
When should I shut the sash?
Shut the sash whenever you are not actively working in the fume hood. Remind yourself to shut the sash every time you walk away from the hood.
What other fume hood practices can reduce my energy consumption?
First of all, never use a fume hood just for storing chemicals – they belong in a safety cabinet, which doesn’t use huge volumes of air. If your fume hood has an occupancy switch, turn it off when not in use. If your group is no longer using a specific fume hood, consider having it locked and de-commissioned so air no longer flows through it.
What if my experiment has cords or tubes?
Some experiments involve power cords or tubing that prevents full closure of the sash. In most cases, if sashes are closed to the cord/tube, your participation will not be significantly impacted.
How do you calculate energy savings of the competition?
We compare the fume hoods’ air flow during the competition to the baseline period before the competition. This is monitored through the building management system which samples and stores data every few minutes. We then calculate the energy needed to heat, cool, and move that air. The more you shut your sash, the more air flow is reduced, and the less energy you lose!
You can check out an interactive fume hood energy calculator here: http://fumehoodcalculator.lbl.gov/
Question or Comments?