Laminar Flow Hood

A Laminar flow hood or cabinet is an enclosed workstation. It creates a contamination free work environment. Filters capture all particles entering the cabinet.

• These cabinets protect the work from the environment. They are useful for the aseptic distribution of specific media and plate pouring.
• Laminar flow cabinets are similar to biosafety cabinets. The only difference is that laminar flow cabinets draw effluent air toward the user face.
• A biosafety cabinet protects both the sample and the user. A laminar flow cabinet protects only the sample, not the user.

Laminar flow hoods are expensive. You must change their filters regularly. You must also clean the flow hood with bleach everywhere before and after each use. A UVC bulb with a timer helps before use.

Fume hood vs laminar flow vs biosafety cabinet: which one, when

These three look superficially similar. They are all boxes with airflow and a sash or window. They protect different things. Picking the wrong one is either dangerous or pointless.

• Fume hood: protects the user from what is inside the enclosure. Contaminated air is pulled away from the operator and exhausted. The exhaust goes straight outside or through carbon filtration. The airflow does not keep the work clean.
• Laminar flow cabinet: protects the sample or work from the environment. HEPA filtered air sweeps across the work in one direction. The air blows out toward the user face. This works for keeping dust and airborne contaminants off something you pour or assemble. It actively harms anything you don not want to breathe.
• Biosafety cabinet: protects both sample and user. It looks like a laminar flow hood. The airflow pattern is different. Intake air draws in at the front to protect the user. HEPA filtered recirculated or exhaust air protects the sample. For Class II cabinets, exhaust air receives HEPA filtration again before leaving. These cabinets cost more and need more maintenance. They do both jobs.

For electrochemistry work the choice is usually easy once you ask what you fear:

• Volatile solvent electrolytes like acetonitrile, THF, and carbonates belong in a fume hood. See Drying Solvents for details. Acid and base handling belongs in a fume hood. Anything you formulated after reading Section 2 or 9 of an SDS belongs in a fume hood. See Material Safety Data Sheets. You are protecting yourself from the electrolyte. Reference electrode filling with volatile fill solutions also belongs here.
• Sterile bio electrochemistry prep belongs in a laminar flow cabinet. Pouring media and handling cell cultures or biofilms for a bioelectrochemical system requires sterility. Airborne contamination would ruin the experiment. The material itself is not a hazard to you.
• Sterile prep involving anything pathogenic or otherwise hazardous to the user requires a biosafety cabinet, not a laminar flow hood. A laminar cabinet blows contaminated air at your face. That is the wrong tool. This case is rare in a hobby electrochemistry context.

Short version: if the danger is in the box, use a fume hood. If the danger is outside the box and you protect the sample, use laminar flow. If it is both, you need a biosafety cabinet. Do not use a compromise between the other two.

See also

• Electrochemistry. The hub page for the electrochemistry cluster. The decision to work in a fume hood or laminar flow cabinet begins with what electrolyte you handle.
• Material Safety Data Sheets. How to read an SDS before formulating an electrolyte. Specific sections tell you which containment you need.
• Drying Solvents. Volatile organic solvents like THF, acetonitrile, and carbonates all belong in a fume hood.
• Fumehood. DIY fume hood build notes, lining materials, and utility pass throughs.
• Standard Operating Procedure. Cell assembly and sparging within whichever enclosure is appropriate.