Transfer air & room exhaust calculations & system calculations

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I am trying to use Trane Trace 700 to calculate my room airflows and system airflows & load requirements for the room air balance diagram show in the snip it below, also attached.

I have set up a Trace model with the 3 spaces shown (CIRCULATION 196, ANTE ROOM 115, & CONTAINMENT SUITE 116). I have input information for exterior walls, windows, doors, lighting loads, & miscellaneous loads. I want Trace to do the usual load calculation for these spaces but also include the transfer air requirements. I'm having trouble getting the transfer air to be included in the room and system level airflow calculations. See snip it below & attached for my inputs in the Create Rooms - Airflow Tab for each of the 3 spaces mentioned.

The resulting System & Room Checksums are attached. The transfer air is not being calculated correctly. CONTAINMENT SUITE is negative but not by 100 CFM as it should be. CIRCULATION supply air and return air are equal which is also incorrect, 100 CFM of the supply air (which is greater than the 89 CFM calculated, I'll have to artificial bump this up to at least 100 CFM) should be couted as transfer air to CONTAINMENT SUITE, therefore there shouldn't be any return air for this space.


1. Has anyone been successful specifying a transfer air value vs letting Trane Trace 700 calculate it? If so, how?

2. Does anyone know why my transfer air from CIRCULATION isn't being calculated in the return air value? Again, is there a way to set the transfer air from a space? If so, how?

3. Does anyone have recommendations how to potentially fix this (under create rooms - airflow tab, system level, or potentially other ways)?

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Brad Eisenbarth, CDT
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T 314.425.8799

Eurek, John S NWO via Trace-users's picture
Joined: 2016-05-18
Reputation: 0

Hi Brad-

Interesting predicament. Common question.

115, and 115 should have the adjacent room set as 196. That would match the
flow from your diagram.

That should change your results, but probably won't fix them.

Next thing is that it looks like the total system ventilation is 101 cfm.
The TRACE air transfer is controlled based on the room ventilation. You
can't exhaust more than you have ventilated (vent+infiltration)

For instance, I created a simple file with similar room names and I set 101
cfm of ventilation to 196. That seems to get it right, except for the
Algebra for Room 116 "SA" because TRACE will not count transfer air as
Supply air.

See the attached file and let me know if you have questions.

Bob Fassbender

Eurek, John S NWO via Trace-users's picture
Joined: 2016-05-18
Reputation: 0