Laminar air flow FFU, if it is based on its name and abbreviation is more directed to the airflow pattern that forms a laminar or sweeping pattern, this is the output of the supply and low return placement configuration, if the return position is not made on the bottom side or under the floor on the bottom side, then the air will not produce a laminar pattern.
LAF will often be associated with the amount of ACH (Air Change/hour) why?
I myself often distinguish ACH into 2.
1. ACH, which is defined as a certain amount of air supplied and returned to the system for processing entirely in the AHU and components in the air conditioning system such as per-medium-hepa filters and other components.
This means that the more air circulates into the AHU and its complementary components, especially the filter, the cleaner the air produced.
The login is simple, the more often we sweep the dirty floor, the cleaner the resulting floor.
2. There is ACH which is interpreted by the total air in the room which is replaced in total with fresh air within 1 hour.
This will greatly affect the IAQ value in the room. The bigger the FA that comes in, the healthier the air in the room.
In the application, both definitions are used. it's just that the determination of flow tends to be based on the definition of ACH at point 1. where the total volume x ACH = the value of the flow supplied by the AHU into the room. plus the amount of FA that is intake into the system based on the number of people, the size of the fixed opening ex-filtration / air loss in the room and or for the purposes of a positive pressure room.
So what does this have to do with LAF?
LAF is certainly very related,
I often meet with colleagues or contractors, the term LAF is often leaned on the HEPA section box above the ceiling of the room, some are equipped with FFU or only HEPA housing.
For class 100,000, the average total ACH is made directly on the AHU and 1 packet directly in the hepa. it means that there is no addition of FFU, while for classes 1000, 100 and other lowest particle classes ACH is created on the filter only, namely by adding FFU (fan Filter unit), the fan is added to chase ACH above the average 25-30 ×, some are 100× 200x and so on depending on the cleanliness class according to GMP recommendations / other standards.
If the clean room class 10,000 total ach is backed up by the AHU, the energy used is very high because the air mass load in m3/h is very large. therefore the FFU is added so that the total ACH is pursued only by the filter.
Post time: Nov-14-2022