“Class 100 environment” means an ISO class 5 atmospheric environment, which contains less than one hundred (100) particles:
a. 0.005 microns in diameter per cubic foot of air.
b. 0.05 microns in diameter per cubic foot of air.
c. 0.5 microns in diameter per cubic foot of air.
d. 5 microns in diameter per cubic foot of air.
Answer:(c). Class 100 environment” means an ISO class 5 atmospheric environment, which contains less than one hundred (100) particles five-tenths (0.5) microns in diameter per cubic foot of air, according to the ISO for clean rooms and associated controlled environments.