[Trace-users] Ventilation Rate

Hintz, Scott F ScottF.Hintz at trane.com
Tue Apr 6 14:34:23 PDT 2010


The ECB subcommittee of SSPC 90.1 has ruled on an interpretation request for G3.1.2.5 stating the total outdoor air ventilation for the proposed and baseline buildings (remember that cfm is a rate) must be the same. So, if you're modeling for LEED, have TRACE run the Standard 62.1 calculations on the proposed alternative. Next, convert the resulting total OA cfm from the proposed into cfm/sqft and enter this as cooling and heating ventilation values in each room for the Appendix G baseline alternative. Do not run the 62.1 calculations on the Appendix G baseline alternative. As long as the schedules are the same between the proposed and baseline alternatives, the hourly ventilation values will also match. It is easiest to apply the new ventilation rate within the Airflows Templates.

Scott Hintz, LEED(r) AP BD+C
C.D.S. Engineer III
Trane Commercial Systems
Ingersoll Rand
3600 Pammel Creek Road
La Crosse, WI 54601-7599

Office (608) 787-3926
Fax (608) 787-3005
Email: cdshelp at trane.com<mailto:scottf.hintz at trane.com>
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From: Wilson, Luke [mailto:LWilson at integral-group.net]
Sent: Tuesday, April 06, 2010 6:46 AM
To: Craig Gann
Cc: trace-users at lists.onebuilding.org
Subject: Re: [Trace-users] Ventilation Rate

Thanks to all for the replies. So to summarize: the system level ventilation rate should be the same in both cases, but Trace doesn't have a way to specify system level ventilation.

From: Craig Gann [mailto:cjg04austin at swbell.net]
Sent: Monday, April 05, 2010 4:48 PM
To: Wilson, Luke
Cc: Scott Parker; trace-users at lists.onebuilding.org
Subject: Re: [Trace-users] Ventilation Rate

To expand on the discussion..... minimum ventilation rates at the space (room) level are defined by ASHRAE 62, however the design quantity of ventilation air (cfm) introduced into the system must be the same for both proposed and baseline designs. How that ventilation air is controlled at off-peak conditions (such as with DCV, etc) is where the potential energy savings are for the proposed design. In other words both designs must introduce the same ventilation cfm at the design condition. The design ventilation quantity is to be calculated per the ASHRAE 62.1 version applicable to the particular LEED version you are using.


Craig J. Gann, P.E.; LEED AP

On 4/5/2010 3:27 PM, Wilson, Luke wrote:
Thanks for the reply.
So the minimum ventilation rates that Appendix G is referencing is on the space level and not on the system level?

From: Scott Parker [mailto:sparker at aeieng.com]
Sent: Monday, April 05, 2010 4:25 PM
To: Wilson, Luke
Subject: RE: Ventilation Rate

You will have the same outside air per person or per area rate in the templates when you create a new alternate based on the Alternative 1.  If your system type changes so that you have a more efficient introduction of outside air, and thereby reduce the total outside air required, then this is a legitimate savings.  However, you must have the same outside air rates per person or per area (e.g. in a lab if you have a minimum of 6 ACH, once-thru, then you cannot show savings for going down to 4 ACH in the proposed design - I think this is what 90.1 wants to avoid).


From: trace-users-bounces at lists.onebuilding.org<mailto:trace-users-bounces at lists.onebuilding.org> [mailto:trace-users-bounces at lists.onebuilding.org] On Behalf Of Wilson, Luke
Sent: Monday, April 05, 2010 4:03 PM
To: trace-users at lists.onebuilding.org<mailto:trace-users at lists.onebuilding.org>
Subject: [Trace-users] Ventilation Rate

For ASHRAE 90.1 Appendix G, it requires that the proposed and baseline ventilation rates be the same. I have my proposed ventilation rate. Is there a way to input a system level Ventilation rate in Trace?
Any help would be appreciated.

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