Laminar flow hoods
(Also known as laminar flow cabinets, laminar flow closets, tissue culture hood or clean benches. )
Laminar flow hoods are specialist hoods that are designed to prevent the contamination of any particle sensitive device, biological samples or semiconductor wafers. They are particularly important pieces of equipment in any tissue culture laboratory as they provide a 99% sterile area in which to work. Laminar flow hoods work by sending lab air through a HEPA (high efficiency particulate) filter that removes 99.99% of all airborne particles such as dust, spores and mycelia. The filtered air is delivered into an enclosure open on one end.
The principle is similar to ductless fume hoods in that air is drawn through a HEPA filter (a high efficiency bacteria-retentive filter) and is then drawn towards the user is a very smooth laminar flow.
Laboratory air is taken into the laminar flow unit and passed through a pre-filter to remove large particles such as dust. The air is then compressed and channeled through the HEPA filter (High Efficiency Particulate Air filter) in a ‘laminar flow’. Laminar flow is where the purified air flows out over the entire work surface in parallel lines at a uniform velocity.
The cabinets or clean benches are usually made of stainless steel with no gaps or spaces where contaminating substances or spores may gather.
Laminar flow hoods or clean benches come in both horizontal and vertical layouts. The cabinets come in a rage of sizes and with a variety of airflow patterns.
NSF49 is the usual regulatory standard for these laminar flow cabinets.
Some laminar flow cabinets come with a UV-C germicidal lamp to sterilize unit and its contents when not in use. It is very important that the UV-C germicidal lamp is turned off when not in use as it can cause burns to exposed skin and cataracts.
Cleanrooms
A cleanroom (sometimes called a clean room) is a large room, area or environment, typically or scientific research or specialist manufacturing where the area has a very low level of particulate contaminants as dust, microbes, chemical particles and fumes.
Cleanrooms can be quite enormous. Entire factories can be a cleanroom environment. Industries where they can be found include chemical manufacturing, semi conductor manufacturing, biological, medical and biochemical research. In fact any manufacturing process or scientific research that is sensitive to atmospheric pollutants might use a cleanroom.
The operating principles of cleanrooms are similar to laminar flow hoods in that air entering the cleanroom from the external environment is passed through a filter which excludes dust and other large particles. The air inside the clean room is constantly passed though a HEPA filter to remove any pollutants that have been created internally.
Staff who work in a clean room usually have to wear a special cleanroom suit and shoes with completely smooth soles that do not attract dirt and dust.
Read more:
What are fume hoods?
Fume cupboard technical terms and definitions
How do fume cupboards work?
What are fume cupboards used for?
Tips on ductless fume cupboards
Tips and advice of ducted fume cupboards
What are clean benches?
Health and Safety issues concerning fume cupboards
