Forum discussion
NC-2009 IEQp1: Minimum IAQ Performance
My project is a 93,000 sf open-plan hangar. We are designing grills on walls that count for 4% of the floor area on 2 opposite facades to induce crossed-ventilation. Has anyone tried this strategy successfully in a project before?
My concern is that it is a big space and I am afraid the reviewer will ask for mechanical ventilation.
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Is outdoor air quality testing required in a space using natural ventilation?
What options are available to projects outside the US to meet this prerequisite?
Can LEED 2009 projects elect to follow ASHRAE 62.1-2010 for this prerequisite?
Which units should be included in the calculations for this prerequisite?
Andrew Mitchell, P.E.
PrincipalMitchell Gulledge Engineering, Inc.
LEEDuser Expert
126 thumbs up
November 6, 2015 - 8:26 am
For natural ventilation, all occupiable space should be within 25' of an opening. If you do not meet this, then I would recommend adding exhaust fans to draw the ventilation air through the openings. You are allowed to control this based on CO2 levels in the space.
Joseph Snider
PrincipalIntegrative Sustainability Solutions
51 thumbs up
November 6, 2015 - 9:49 am
As Andrew has noted, if any part of the space is further than 25' (8 m) away from those openings, the LEED reviewers will have a questions. We have used a similar strategy on large warehouse and manufacturing spaces in multiple LEED projects in Colombia and Venezula. In those cases though, there was a ridge vent in addition to the side wall louvered openings. This works as a stack event and air comes in the sides and is exhausted out the top. These can even be mechanical exhaust fans for not too much cost. When the fans were passive and not mechanical, we had to provide documentation of an engineered natural ventilation system showing how the air would move through the space and how that was more than enough air than required by ASRHAE.
Gustavo De las Heras Izquierdo
LEED Expert185 thumbs up
November 11, 2015 - 8:02 pm
Thanks for your comments,
If I could use Section 6.4.1.2. of ASHRAE 62.-2010 I would be able to comply with natural ventilation. Can I use 2010 version instead of section 6.4 - ASHRAE 62.1-2007?
"6.4.1.2. Double side openings. For spaces with operable openings on two opposite sides of the space, the maximum distance from the operable openings is 5H, where H is the ceiling height"
Annalise Reichert
Project Managerstok
5 thumbs up
December 15, 2015 - 1:59 pm
I am working on a similar project, a 45,000 sf warehouse that is part of an Electrical Training Facility to train electrical contractors. The warehouse is primarily used for storage of educational materials, however a small section (about 2,000 sf) is used for an hour long training session 3 times per week. The facility manager considers this space unoccupied.
The warehouse perimeter wall has large roll-up doors that are manually opened in the morning, and manually closed at night. 3 large rooftop exhaust fans run continuously throughout the building's hours of operation.
To demonstrate that the unoccupied space meets ASHRAE 62.1 minimum ventilation rates, I am using the engineered natural ventilation approach to show the exhaust fans induce outside air from the doors throughout the warehouse space. My question is, do the roll-up doors need to have automatic controls, or is manually opening them acceptable? Additionally, do the rooftop exhaust fans need any sort of control or is it adequate that they turn on and off based on the facility operating schedule?
Gustavo De las Heras Izquierdo
LEED Expert185 thumbs up
December 21, 2015 - 8:09 pm
1. According to LEED definition of regularly occupied space I think your warehouse cannot be considered as unoccupied.
2.In the VRP calculator you should use peak occupancy (but you should also consider the diversity factor)
3.Taking into account this is an engineered system, I think there is no specific requirement for the controllability of the roll-up doors. The outdoor air will enter the building through cracks and gaps in the envelope.
4.Based in my experience, I have never been asked to provide a minimum control or schedule, but it needs to be properly commissioned and meet the OPR.