Class 100 is an atmospheric environment defined as containing fewer than how many particles 0.5 microns in diameter per cubic foot of air?

Class 100 is an atmospheric environment defined as containing fewer than how many particles 0.5 microns in diameter per cubic foot of air?

• A. 100 particles 0.5 microns in diameter per cubic foot of air
• B. 1000 particles 0.5 microns in diameter per cubic foot of air
• C. 10 particles 0.5 microns in diameter per cubic foot of air
• D. 1 particle 0.5 microns in diameter per cubic foot of air

Answer: (A)

Air cleanliness classifications use how many particles of a certain size are present per a volume of air. For Class 100, the air must have 0.5 micron or larger particles at a count of 100 or fewer per cubic foot. That means the maximum allowed is 100 particles per cubic foot; exceeding that places the air in a less clean class (e.g., Class 1000). This single-number standard gives a practical way to quantify and control contamination risk in environments requiring tight particulate control.

Air cleanliness classifications use how many particles of a certain size are present per a volume of air. For Class 100, the air must have 0.5 micron or larger particles at a count of 100 or fewer per cubic foot. That means the maximum allowed is 100 particles per cubic foot; exceeding that places the air in a less clean class (e.g., Class 1000). This single-number standard gives a practical way to quantify and control contamination risk in environments requiring tight particulate control.