It is my understanding that USP <797> requires a minimum of 30 air exchanges per hour in both buffer and ante rooms. In buffer rooms up to 1/2 of the air exchanges can be provided by operating Laminar Flow Hoods. Eric would you please comment on the following....In a negative pressure buffer room containing MIC hoods exhausted to the outside, 30 air exchanges would be required because the air filtered by the MIC hood is not re-circulated into the buffer room....it is vented to the outside. We are having a disagreement with our architects/designers, we feel that we need 30 ACH and they are of the opinion that 15 ACH is sufficient because they are assuming 15 ACH are "donated by the MIC hoods. Am I correct in saying that ante rooms also require a minimum of 30 ACH?
I will not comment on the performance of the MIC isolator and the design specifications of the room where this isolator is located because of a lawsuit that I was dragging into while being an AJHP reviewer of an article that was published in AJHP evaluating the performance of four isolators. The manufacturer sued AJHP and the article authors over the article and thankfully lost the case and the appeal in having to compensate AJHP and the authors for legal fees. We live in a very litigious world. I have attached a copy of the chapter and article in question. I have no current working knowledge of how these isolators perform relative to the requirements of the chapter. You correct about the 30 ACPHs per hour in the ISO Class 7 buffer and ante area if the isolator does not meet the performance requirements detailed in the chapter: "Placement of Primary Engineering Controls". If you like, you can contact Jim Wagner (jimwagner@cenvironment.com) and he may be able to help you.
