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external/lab-equipment/hoods/hoods.md

+# Laminar Flow - Fume Hood - Biosafety Cabinet: what are the differences and when to use them?
+
+At LCSB, you can find different types of hoods. In order to work in a clean and safe environment, it is important to know what are the differences between the different hoods and when to use them. To help you to identify the different hoods, each of them has a sticker reminding the protection it offers.
+
+For any issue regarding a hood, please send a [ticket](https://service.uni.lu/sp?id=sc_cat_item&sys_id=be0873f8db7070505c72ef3c0b96199f&sysparm_category=af924f17dbac38105c72ef3c0b96194b) to the Support Team.
+
+For any concern regarding safety or quality, please send a ticket [here](https://service.uni.lu/sp?id=sc_cat_item&sys_id=4343cc0ddbb070505c72ef3c0b961932&sysparm_category=cca7f2c1db683c905c72ef3c0b961940).
+
+![](media/image1.png)
+
+## Laminar Flow
+
+A (vertical or horizontal) laminar flow is used when there is a need for
+sample protection. It can be used only when the user does not have to be
+protected from any biohazard or chemical risk, has a laminar flow does
+not protect the user at all.
+
+![](media/image2.png)
+
+## Fume Hood
+
+A fume hood is used with volatile chemical compounds. The air is drawn
+out of the hood directly to the exhaust air. It can be used only when
+the sample and the user do not have to be protected from any biohazard
+risk. The fume hood is not a sterile environment.
+
+![](media/image3.png)
+
+## Biosafety cabinet (BSC)
+
+A BSC is used when a sterile environment and/or protection of the user
+against biohazard risks are needed. The biohazard protection of the user
+is ensured by an air aspiration at the entrance of the BSC, creating an
+air curtain minimizing the escape of aerosols. 70% of the air extracted
+from the BSC is filtered by a HEPA filter and blown back in the BSC,
+ensuring a sterile vertical flow. 30% of the extracted air is filtered
+by another HEPA filter and blown to the laboratory. Therefore, BSC are
+not protecting the users against chemicals risks.
+
+![](media/image4.png)
+
+## Biosafety cabinet (BSC) with thimble connection
+
+At LCSB, we have some BSC with a thimble connection allowing to work in
+a sterile environment with volatile chemical compounds. Thanks to the
+thimble connection, the 30% of the air that are blown in the laboratory
+in a normal BSC configuration are blown drawn in the exhaust air of the
+building. This kind of hood is providing a sterile environment for the
+sample protection and a protection of the user against biohazard and
+volatile chemicals.
+
+![](media/image5.png)
+