#The space in between two air locks pdf#
#The space in between two air locks series#

#The space in between two air locks pdf#

ASHRAE Research Project RP-1431 established a new terminology called contaminant migration rate, or contamination rate ( CR), for cleanroom applications.ĪSHRAE Members have free access to the full-text PDF of this article as well as the complete ASHRAE Journal archives back to 1997 in the Free Member Access Area. To identify the performance and effectiveness of various barriers (airlock, single door, mini-environment, or isolation chamber, etc.) to contain contaminant migration, it is necessary to establish a quantitative measure so various “contaminant migration barriers” can be compared or optimized for better performance. Quantitative Measure of Contaminant Migration Across Barrier

Even if a room is equipped with a fast-response (1 to 3 seconds) VAV air supply system to provide extra surplus air, it is not fast enough to prevent an airborne cross contamination. This is because airlock rooms usually do not have sufficient surplus supply air to maintain the required pressure differential needed to prevent reverse flow due to air turbulence during door operation. However, when a door is being opened, the room’s air leakage through the door’s opening suddenly becomes much higher than the leakage through minor cracks when doors are closed. Figure 1 shows common types of these airlocks, though alternative pressure relationships can be used in specific applications.ĭoor Operation and Pressure Differential LossĪs illustrated in Figure 1, airlock spaces are typically designed to maintain certain pressure relationships with respect to controlled environments and corridors. In the rest of this discussion, we will use “airlock” as a general term to include both anteroom and vestibule.Īirlocks can be categorized into “cascading,” “bubble,” “sink” and “dual compartment” types each type exhibits different airflow directions and pressure differences between the controlled environment, airlock, and corridor. Table 1 indicates common practices and functions among vestibules, anterooms and airlocks. The most stringent airlocks are often installed for biosafety level 3 and 4 (BSL-3/4) labs and cleanrooms similar, but less stringent mechanisms can be found in health-care facilities such as anterooms in isolation or operating room suites and vestibules in commercial buildings. Poor airlock design concepts may cause undesired migration of chemical fumes, particles, or microbiological agents, which can be toxic, harmful, or infectious, into protective areas, or cause contaminated products or processes from excessive airborne contaminants inside the controlled environments. However, the relative air volume for supply, return or exhaust could vary based on the type of airlock. An airlock area is often ventilated with filtered supply air, with return or exhaust air to exit. The two doors should be interlocked to avoid being opened at the same time.

#The space in between two air locks series#

delegate.Īn airlock is a transitional space that typically has two doors in series to separate a controlled environment (such as cleanroom, lab, operating room, or isolation room) from a corridor, or vice versa. He served as IEST society president in 2016 – 17 and as ISO/TC 209 standards U.S. He is an ASHRAE Distinguished Lecturer and past chair of ASHRAE TC 9.11. Wei Sun, P.E., is president of Engsysco with offices in Ann Arbor and Farmington Hills, Mich.