Health Care - Negative Isolation Rooms.
Health Care - Negative Isolation Rooms.
(OP)
Im having trouble trying to get some legit answers on if i should be using the supply or the exhaust to calculate ACH for negative isolation rooms. One would think that this would be obvious, as i was told that ACH is always calculated from the larger of the 2. However, i just read an ASHRAE document that states "12 ACH on supply air as minimum". And also the original commissioning documents are based on supply air.
My co-workers think I'm wasting my time and over thinking this. Am I?
Thanks
My co-workers think I'm wasting my time and over thinking this. Am I?
Thanks





RE: Health Care - Negative Isolation Rooms.
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RE: Health Care - Negative Isolation Rooms.
RE: Health Care - Negative Isolation Rooms.
TTFN
FAQ731-376: Eng-Tips.com Forum Policies
[IMG http://tinyurl.com/7ofakss]
Need help writing a question or understanding a reply? forum1529: Translation Assistance for Engineers
Of course I can. I can do anything. I can do absolutely anything. I'm an expert!
There is a homework forum hosted by engineering.com: http://www.engineering.com/AskForum/aff/32.aspx
RE: Health Care - Negative Isolation Rooms.
Question 2: why don't we consider the air coming to a space by infiltration as a supply air for pressure calculation purpose.?
ASHRAE follows fluid mechanic, not fluid mechanic follows ASHRAE
RE: Health Care - Negative Isolation Rooms.
And to my understanding, air pulled in through the openings is considered an air change, as in its not the same air that was in the room before, which could potentially be full of nasty stuff. Its not an "outdoor air change", which, yes, would be based on fresh air from the inlet. Outdoor air changes and air changes per hour have different requirements, the former being a portion of the latter. I'm not trying to argue the terminology here, i just want to know why I'm getting contradictory information, and i want to make sure i'm doing things correctly.
For example, here is a document from 2014 that would appear to support my original position that ACH for AII rooms is based on exhaust flow, as stated by urgross.
Link
Which was fine until i found this document that states on page 15 "12 air changes per hour on SUPPLY air as a minimum".
Link
Also, as i mentioned, the original commissioning docs are based on supply air, which is adding to the confusion.
The reason this is important is, I have I have to know which of the flows (supply or exhaust) needs to remain constant to meet ACH requirements, and which one i can manipulate to achieve the pressure i want.
RE: Health Care - Negative Isolation Rooms.
RE: Health Care - Negative Isolation Rooms.
if you consider infiltration or door opening then your exhaust would be equal to your supply, then you don't need to use any document since you have 1000 cfm exhaust and (800cfm from supply duct +200 cfm from infiltration) are running in your room.
RE: Health Care - Negative Isolation Rooms.
urgross, im going to get myself a copy of the documents you mentioned, so i don't have to rely on third hand information.
Awesome, thanks all.
RE: Health Care - Negative Isolation Rooms.
RE: Health Care - Negative Isolation Rooms.