Pressurization technology utilized in cleanroom facilities is typically used to minimize airborne contamination from less-clean rooms into a cleaner room. Pressurization design has been traditionally based on intuitive suggestion instead of well-established guidelines. A pressure differential of 0.05 in. (12.5 Pa) as a single and uniform criterion is believed to be oversimplified for more complex conditions, such as when an auxiliary device is utilized inside a cleanroom.

As the second part of the research, the research team quantitatively evaluated the effectiveness of common auxiliary devices in room cleanliness control, such as a clean bench, a mini-environment, a containment hood, and a pressure stabilizer. It was found that some of these devices could contribute to a possible reduction in room cleanliness requirements, air change rates, or pressure differential values, while others may not. A summarized table is included as a general recommendation, along with the minimum pressure differential table listed in Part 1 of this research (Sun 2013).