Little chemical, BIG SMELL: Leave it to a pinch of beta-mercaptoethanol to overpower the lab. While not every chemical has such a pungent reminder about where it should be handled (hint: not at the bench), a good rule of thumb is to make use of your chemical fume hood whenever possible!
We looked recently at the types of hoods that can be found around your research center (Beginners Guide to Fume Hood and Safety Cabinets). If you’re planning to run an experiment in one, here are a few tips to help you prepare:
1. Check the pressure gauge
Fume hoods run 24/7/365 except during maintenance. It’s a good idea to check the gauge before setting up inside. Otherwise, running that experiment will be no different than if you ran it at your desk, on the bench or everywhere you have the potential to expose everyone around you to the effects of hazardous reagents.
2. Check for signage on the face of the hood
You’re looking for a placard that describes whether or not the airflow is out of range for work with specific items, like carcinogens. In some cases you may need to use a different hood. Signs will also indicate whether the fume hood is currently out of service.
3. Turn on the light to see clearly
You may think this one sounds obvious but it is easy to forget, especially if you are only working in your hood for a short period. Having the light switched on allows you to see better and avoid accidents. If you’re working in a fume hood you are likely working with chemicals you want to avoid spilling – so switch on the light, it only takes a second.
4. Tell your coworkers before experimentation
Along with tip #7 (removing extra stuff like sample preps that can belong to everybody in the lab), it’s common courtesy to give a “heads up” so others know what specific materials are in use. On top of that, if there’s only one shared hood it’s a good idea for people to book it on a calendar; then you can make plans around each other’s experiments.
5. Wear your PPE
Although an enclosed workspace does offer great protection against gases, fumes and an assortment of other physical hazards, this protection is still complimentary to what you gain while wearing PPE. Whether you’re handling hazardous reagents or performing another technique like perfusions, for example, in combination with the glass sash, gloves, lab coat and goggles help protect against the risk of accidental spray from saline (or formalin!) from a flow pump dialed too high. Just remember to choose the right glove for what you are working with, they’re certainly not all equal!
6. Baffled on how to set up?
Don’t be! Whether you’re about to generate vapor products that are heavier than, as heavy or lighter than air, you can adjust the baffles to ensure that the fume hood continues to catch away that bad air inside the hood. Check out this handy guide with pictures from the University of California San Diego to show how adjusting baffles affects air flow.
7. Remove extra clutter
Too many flammable and combustible items set the stage to repeat the story of this 2004 lab accident. When you run an experiment, prepare your workspace with only the essential items you need. Fume hoods should not be used for storage or disposal of waste materials, so remove everything you have been using once you are finished.
8. Set up your workspace strategically
a. Keep flammable reagents away from heat sources.
b. Keep electricals away from water.
c. Larger, taller items should be placed towards the back.
d. Reagent containers should be physically separated from waste containers (not side by side).
e. Primary and waste container bottles should look and be sized differently.
f. Aim for the center of the workspace, or at least a few inches from all sides.
9. Maintain your airflow
To keep bad air from pooling in nooks and crannies, it’s important to ensure that air can flow around and above your equipment just as much as it can flow underneath it. Many pieces of small equipment have legs to stand up and off the bench. For light equipment that doesn’t, try inverting a couple of those white, plastic conical or test tube holder racks side-by-side and use that as a stage to lift them up.
10. Adjust the sash
The lower you position it, the more protection you gain.
One interesting item of note is that your fume hood acts as a gigantic exhaust for the building’s ventilation system. What that means is when they’re shut down for maintenance you may find the laboratory room temperature fluctuate by several degrees. It’s nothing to be worried about in terms of safety, but if a particular assays is temperature sensitive, it’s something to keep in mind.
Lastly, the biggest pitfall that scientists make when using a fume hood is actually working with their head inside of it where bad air goes straight up to where they breathe. Remember that three of the easiest ways to help ensure your protection with a fume hood is to keep your head outside of it, wear your PPE and to keep the sash lowered!