Interesting Iso Room Design
Interesting Iso Room Design
(OP)
Here's the situation: I have a small (~14x16) iso room which I am designing. To achieve the required ACH (including the anteroom, restroom, etc), I need a unit to produce 411 cfm.
Here's the problem: 411 cfm of 100% OA doesn't really work well with a DX system (Location is in Houston, Texas - 98/80 design conditions) and the closest chiller is about 600' away (requiring a pump producing 7.7 gpm at ~70' head). I have though about using some type of heat recovery, but I am not really sure that I can use potentially contaminated air to pre-treat the supply air (I know they won't mix - I am more concerned about exposure to the technicians when they clean coils, etc.).
Any suggestions on the best type of unit/combinations to used for this situation?
Thanks.
Here's the problem: 411 cfm of 100% OA doesn't really work well with a DX system (Location is in Houston, Texas - 98/80 design conditions) and the closest chiller is about 600' away (requiring a pump producing 7.7 gpm at ~70' head). I have though about using some type of heat recovery, but I am not really sure that I can use potentially contaminated air to pre-treat the supply air (I know they won't mix - I am more concerned about exposure to the technicians when they clean coils, etc.).
Any suggestions on the best type of unit/combinations to used for this situation?
Thanks.





RE: Interesting Iso Room Design
RE: Interesting Iso Room Design
According to AIA Health Care Guidlines, iso rooms are 100% exhausted unless you return the air through HEPA filters and only to the system serving that room. So to use a parallel box you'd have to add HEPA filters in the return system somehow which adds a lot of pressure loss that I'm not sure a parallel box could handle.
@dblyle
Take a look at this article:
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RE: Interesting Iso Room Design
RE: Interesting Iso Room Design
Preferably, the exhaust fan will have all maintenace items outside of the air stream, especially the belt, backflow damper and end switch (if using the end switch for AHU shutdown). If not for toxic compounding, air can be recirculated.
I had considered using the interstitial space, but do not like to consider that equivalent to outside air (separate string, no guidance known outside of IMC). Potential for renovation work in the interstitial, and potential for ACM in older buildings, makes this shaky.
Not sure why a restroom would be included on air flow; if a renovation you'll be getting 30 ACH, if new 45 ACH, minimums, just in the ISO 7. If worried about energy, then put the restroom (or any non-regulated space) on a separate system. At 14' x 11', you must have a low ceiling to only be sending 411 cfm to make 30 ACH.
RE: Interesting Iso Room Design
That way, you only have exhaust fan HEPA filtration system.
RE: Interesting Iso Room Design
RE: Interesting Iso Room Design
Can anyone think of the disadvantage of an ERV connected to a RTU? The only thing I can think of is that the exhaust air would pass thru a coil before being ejected.