[Bldg-sim] GBCI approval of carbon monoxide control of garage fans?

[Nathan Miller]

I know this is a contentious issue on bldg-sim regarding whether this
should be a allowable measure or not. 

 

I can tell you that on a recent office building project (LEED-NC v2.2) we
submitted for energy savings from garage CO sensors. The only comment we
got from the reviewer was that "ASHRAE mandates some sort of timed control
or CO control as part of the mandatory measures," so we couldn't compare
against a 24/7 constant volume system. I wish they had quoted a specific
section of 90.1 for clarity. 

 

We switched the baseline system to be off for ~6 hours during the night
(not in agreement with the IMC requirement for continuous air movement),
and they accepted our energy savings.

 

Our proposed case simply had the fans on a VFD and we created a custom
schedule, which we presented to the reviewer, to reflect that the fans
typically were at their lowest setting, and only ramped up for peak
commuting hours (small peaks for morning and lunch, big peak at end of the
day when all the cold engines start up and really put out the CO). 

 

It is unclear to me if you are modeling a residential garage, where there
may genuinely be 24/7 use, if you get to compare to a 24/7 constant volume
system. 

 

Nathan Miller

Senior Energy Engineer/Mechanical Engineer

direct: 206.788.4577

fax: 206.285.7111 

 

From: bldg-sim-bounces at lists.onebuilding.org
[mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of James Hansen
Sent: Thursday, November 12, 2009 8:09 AM
To: bldg-sim at lists.onebuilding.org
Subject: [Bldg-sim] GBCI approval of carbon monoxide control of garage
fans?

 

Does anyone know if the GBCI reviewers are currently accepting ECMs based
off of garage carbon monoxide sensors to index garage fans?  Or if this
can actually be included in the model with appropriate explanation?

 

IMC requires constant ventilation for enclosed garages, but allows
CO-based systems to activate the fans.  This equates to a substantial
energy savings since most systems like this only operate a few hours in
the morning, evening, and at lunch (other than the minimum 0.05 cfm / sq
ft continuous ventilation required by the IMC).

 

If we explain the system, and explain our assumptions for the use
schedules that dictate the proposed building fan schedules for the garage,
is this acceptable?

 

Do they require any backup support/studies for exactly how often the CO
levels will rise above acceptable limits, or is it sufficient to make a
conservative assumption that the garage fans will operate from 7-9am,
11-1pm, and 4-6pm at full load?  In my engineering experience, CO-based
systems rarely run, and the circulation fans throughout the garage (which
approximate the continuous 0.05 cfm / sq ft requirements of the IMC
CO-based systems) are what really prevent isolated CO buildup.

 

Thanks in advance,

 

GHT Limited
James Hansen, PE, LEED AP

Senior Associate

1010 N. Glebe Rd, Suite 200

Arlington, VA  22201-4749

703-338-5754 (Cell)

703-243-1200 (Office)

703-276-1376 (Fax)

 <http://www.ghtltd.com/> www.ghtltd.com

  _____  

The information contained in this communication is confidential, may be
privileged, and is intended only for the use of the addressee.  It is the
property of GHT Limited.  Unauthorized use, disclosure or copying of this
communication or any part thereof is strictly prohibited and may be
unlawful.  If you have received this communication in error, please notify
me immediately by return e-mail or by e-mail to  <mailto:ght at ghtltd.com>
ght at ghtltd.com, and destroy this communication and all copies thereof,
including all attachments.  Thank you.

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.onebuilding.org/pipermail/bldg-sim-onebuilding.org/attachments/20091112/d660d312/attachment-0001.htm>