[Equest-users] LEED Increased Ventilation ASHRAE 62.1

Jeremy Poling Jeremy.Poling at transwestern.net
Thu Apr 21 09:17:16 PDT 2011


Paul,

 

The standard is using a reduced notation format (not one I generally use
or encourage others to use).  More fully described it should be (bold is
my update):

 

"the region within an occupied space between planes located 3 in and 72
in. (75 mm and 1800 mm) above the floor and more than 2 ft (600 mm) from
the walls or fixed air-conditioning equipment."

 

Basically, draw one plane relative to each surface of the room.  If the
surface is a floor, draw the breathing zone "floor" plane at 0'-3" AFF.
If it is a ceiling, draw the plane relative to the floor at 6'-0" AFF.
If it is a wall, draw the plane 2'-0" perpendicular from the wall.  The
volume enclosed by the intersection of all of those planes is the
breathing zone.

 

Hope that helps with the definition!

 

The problem I usually run into is this definition to begin with.  It
conflicts with the definition for "zone" (renamed to "ventilation zone"
by an addendum), which includes the entire volume of a space or multiple
spaces.  The calculations for breathing zone outdoor airflow use "Az =
zone floor area: the net occupiable floor area of the zone ft2 (m2)."
So for calculation purposes - I don't see any use for the definition of
breathing zone.  The formulas are based on total floor area, not the
area of the lower plane of the breathing zone (0'-3" AFF) and also do
not make consideration for space volume vs. breathing zone volume.  This
is all while calculating Vbz for the breathing zone.

 

Since it usually results in more OA than other methods, I typically
ignore the breathing zone definition for calculation of Az.

 

Any thoughts from the rest of the list?

 

Jeremy R. Poling, PE, LEED AP+BDC



From: equest-users-bounces at lists.onebuilding.org
[mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Paul
Diglio
Sent: Thursday, April 21, 2011 10:16 AM
To: equest-users at lists.onebuilding.org
Subject: [Equest-users] LEED Increased Ventilation ASHRAE 62.1

 

Per the LEED NC V3 requirements in order to qualify for IEQc2 the
ventilation in the breathing zone needs to be increased by 30%.

 

62.1-2007 defines the breathing zone as "the region within an occupied
space between planes 3 and 72" above the floor and more than 2' from the
walls or fixed air-conditioning equipment."

 

I do not understand what is meant by "planes 3".  

Can anyone shed some light on this?  Has anyone has success modeling a
reduced space volume in eQuest or is it easier to perform a manual
calculation and adjust the CFM of outside air per a weighted volume? 

Thank you,

Paul Diglio

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