In the last three decades there has been an increasing emphasis on the importance of the use of fidelity assessment on improving the science of psychological, social, and behavioral research.
A cleanroom is an area or enclosure in which the air has to be cleaned to a defined particle limit, usually in particles per cubic foot. In the United States most cleanrooms are discussed in terms of Classification Limits.
Cleanrooms are classified by the cleanliness of their air. The method most easily understood and universally applied is the one suggested in the earlier versions (A to D) of Federal Standard 209 in which the number of particles equal to and greater than 0.5 m m is measured in one cubic foot of air and this count is used to classify the room.