We have installed air showers for our Clients to comply with requests from the their Clients based in Japan and the far east. Air showers are not something often used in the UK and we question the effectiveness of the air shower.
Recently we visited a Client who required air showers to all four entry change rooms for their ISO Class 7 cleanroom. After surveying the areas and understanding their requests I asked why do you need them?
I was advised that they wanted air showers because the real time particle monitoring results were getting worse inside the cleanroom due to the increase of employees within the room. When I considered the problem a little further the use of an air shower would have been a pointless exercise with a big cost associated with the initial purchase. I explained that they will gown up using sterile clean garments (to cover up their dusty clothes), then proceed into an air shower to clean the clean garment! Then proceed into the cleanroom in the same state as if they hadn’t entered the air shower in the first place.
Once I had explained this process they agreed to what I was saying – we looked further into the problem. I explained that every time they moved inside the cleanroom suit they caused puffs of air the exit the collar and cuffs area containing dust and skin particles that will contaminate the air.
The solution was to introduce a second stage undergarment change area to remove the use of external clothes and use fully closed hoods – the Client has reported improved air cleanliness ever since implementing this change.
An air shower will remove some dust particles from a cleanroom suit – but if its already clean then how effective is it?