Gayanath,
It is a covered area, and I must admit not fully enclosed like a paint booth. We tried a fully covered room, but its visibility was absolutely poor, the technician can not see a thing. I think it is to do with lighting and poor efficiency of our extractor fans they are pretty big, though. We would really need full-scale wind tunnel type room and then series of other issues kiki in as we need a practical separator etc... for small items, we can use the blasting cabinet (hope you have seen it which you put your hands in over a glove)
I like your mobile chamber option and will look into that actually.
(not to show off ) I'm currently working here in the UK and looking for some better options which we could employ in back home Sri Lanka. I have trained our guys with some DVD training program and one-to-one type.
Thanks again