In order to make sure laboratory workers and specimens are protected, labs have fume hoods installed. In fact, it is mandatory for those to be in place if the laboratory deals with toxins or chemicals, as those can cause significant hazards. As a result, it is also vital that all such organizations have good professional relationships with a laboratory fume hood manufacturer.
How Lab Fume Hoods Work
Fume hoods are workspaces that are partially enclosed, with the fume hoods ensuring the air remains clean. This is done either by expelling the air, or by filtering it before returning it. Fume hoods don’t take up a lot of space inside the lab, but they certainly do pack a punch.
They usually have tempered safety glass and the sides and back, as well as excellent visibility. This enables outsiders to view how the experiments are conducted. Naturally, a hood is attached to it as well, as is a sash that can easily be raised so that it can be cleaned and loaded, or opened and close. It is recommended to have a corrosion-resistant fumed hood in place in thermoplastic industries and others where corrosive substances and trace metals are analyzed.
A fume hood has a specified efficiency rating, which indicates how quickly the air flows between the sash and the workspace. Usually, this is indicated in feet per minute. Th higher the velocity of the hood, the quicker vapors and toxins are removed. Laminar flow velocity can be achieved at 100 feet per minute, which is usually the recommended speed. Different hoods work at different velocities, however, and you must make sure that you use the one that is right for the technological or chemical application in which it is used.
Two types of hoods exist: perchloric acid and radioisotope hood systems. The latter is made from stainless steel, which stops radioactive elements from being absorbed. The first stops volatile perchlorate salts from building up inside the hood’s exhaust system.
Five standard hood constructions also exist, being:
- Ductless, which recirculates air after it has gone through a filtration system. This has a higher HEPA rating as well.
- Auxiliary, which uses outside air, which means it also consumes less energy. It also has controls, which help workers to adjust the velocity depending on the sash position. Like the ductless hood, this has a highly-rated HEPA filter.
- Bypass, which provides extra air room, even if the sash is lowered.
- Variable air volume, which are the most sophisticated machines, keeping air velocity at a constant speed at all times.
- Conventional, which ensures exhausted air is at a constant volume, regardless of sash height.
Filtration performance is one of the most important things on good lab fume hoods. Additionally, replacement parts should be kept in place. The laboratory hood’s manufacturing should also have parts available, as well as technical support. Most importantly, however, laboratory operatives must be committed to regularly checking the hoods to make sure they are still fully functional.