On 27/10/2009, at 1:39 PM, Chris Tully wrote:

> 3) Having worked in a Class 1000 clean room lab that was always  
> under a slight positive pressure, there are pluses and minuses.  On  
> the plus side, almost no dust ever built up in side the positive  
> pressure rooms.  On the down side we had to go through an air lock  
> room to avoid too strong of a draft out of the lab.  We did have  
> special synthetic fiber lab coats (no bunny suites) and we each had  
> to bring in a pair of all leather shoes to keep in the locker room  
> for use exclusively in the clean room.  The upside for a micro  
> facility would be less time spent cleaning dust off of equipment and  
> worrying about dust covers.  You could achieve all of this by  
> specifying an ISO 6 (Formerly Class 1000) clean room.  Even if you  
> allowed people to come an go in street clothes/shoes, keeping a  
> fresh sticky mat at the entrance would keep street dirt to a minimum  
> and the filtering implied by a ISO 6 would help a lot too.  Of  
> course this would up the cost a bit...

Positive pressure would seem to be problem if there potentially  
biohazardous samples being imaged?

Regards,

Adrian