Cleanrooms and equipment

What is a typical guideline for the air velocity blown from the ceiling in downflow cleanrooms?

  1. AAbout 30 m/s
  2. BAbout 0.3–0.5 m/s
  3. CAbout 0.001 m/s
Show answer and explanation

Answer: B. About 0.3–0.5 m/s

In downflow cleanrooms, a slow unidirectional airflow of about 0.3–0.5 m/s flows from the ceiling. Too fast causes turbulence that stirs up particles, and too slow cannot carry particles away adequately, so an appropriate velocity is maintained.

Practice this topic Back to topic

More Cleanrooms and equipment questions

  1. In bay-and-chase cleanrooms, how is the cleanliness of the maintenance space behind equipment (the chase) typically handled?
  2. Which element can be released from glass-fiber filters and similar sources and cause unintended doping (contamination) of wafers?
  3. Which is closest to the typical temperature setting of a cleanroom?
  4. Which instrument is used to measure the number and size of fine particles in cleanroom air?
  5. Which item, placed on the floor at cleanroom entrances and elsewhere, removes dust stuck to shoe soles?