A critical addition to cleanroom bioburden comes from people, but how many particles and how that changes when they are still or moving has been little studied. Dastex set up a testing strategy to find out.
When discussing the subject of people as a source of cleanroom contamination, the main focus of attention is “how many particles on average does a person give off per minute?” Very often, in this context, the work of Austin1 is considered. Unfortunately, there are no new studies available on this subject, not even on the question of how particle values compare for employees wearing a cleanroom coat with those for employees wearing a coverall.
To address this lack of data, Dastex set about carrying out a comprehensive study on this subject using the following procedure.
Experimental methodology
The measurement set-up was as follows: A body-testing box was set up on company premises and this provided the basis for the technique of measurement. The principle of measurement process within a body box is described in a guidance note from the IEST.2 A defined cleanroom (with an area of 1.20m by 1.20m) is completely covered with a fan filter unit (FFU) using an H13 filter, while the floor construction is chosen such that the air can be led into the air return shaft with as little turbulence as possible.