[Bldg-sim] Warehouse ventilations to comply with ASHRAE 62.1

James V Dirkes II, PE jvd2pe at tds.net
Wed Jan 26 08:13:08 PST 2011


Dear Ashraf,

 

Think about it.  If you exhaust X cfm, where does the infiltration come
from?  Outdoors!  So you are already introducing hot humid Dubai air into
the building.  A (supply)  ventilation system does the same thing as an
exhaust-with-infiltration system; it pushes instead of pulls.  As long as
the fans actually move the same amount of air, the end result is similar.
(The actual mixing within the space is generally better, though, for a
supply system.)   

 

ASHRAE 62 is not confident that the infiltration actually occurs (the
building can be constructed very tightly), so they generally want you to
have a supply system .  As I think about it, I don't think they require an
exhaust fan, but id the air is introduced, there must be adequate leaks,
louvers or exhaust capacity to let it out.  

 

0.06 cfm / sq.ft. is not much.  For a 30ft tall warehouse. 0.5 cfm/sq.ft.
results in 1 AC/hr., so 0.06 cfm/sq.ft.  is around .12 AC/hr (if the
building is 30 feet tall).  This amount of air certainly won't affect your
indoor environment noticeably if your exhaust system is 5-8 air changes! 

 

It's possible that LEED will buy an explanation which discusses why you can
be confident that the exhaust fans are providing good ventilation because:

.         They are properly spaced around the floor area

.         Operate continuously whenever people are present

.         Move the correct amount of air because there are louvers or other
means to make sure the air can get into the building

 

Good luck!  It sounds as though you really have good ventilation, but need
to make LEED confident about how you are doing it.

 

The Building Performance Team
James V. Dirkes II, P.E., LEED AP
1631 Acacia Drive NW
Grand Rapids, MI 49504
616 450 8653

 

From: Ashraf Khan [mailto:ashraf at mecsd.com] 
Sent: Wednesday, January 26, 2011 9:25 AM
To: 'James V Dirkes II, PE'; bldg-sim at lists.onebuilding.org
Subject: RE: [Bldg-sim] Warehouse ventilations to comply with ASHRAE 62.1

 

James,

 

If we introduce 0.06 cfm.sqft, of outdoor air, if it complies with ASHRAE
requirements, then we can do that.  Normally all warehouses here will be
having ventilators to exhaust air which is assumed that air intake by
infiltration.

 

Also project is located in DUBAI, UAE. Climate here is very hot and humid;
if I introduce outdoor air it will affect the storage materials in the
warehouse. 

 

Did you know where can I find the exhaust rates, such as Toilets, Generator
Room, pump room in ASHRAE?

 

Thanks & Regards,

Ashraf

 

  _____  

From: James V Dirkes II, PE [mailto:jvd2pe at tds.net] 
Sent: Wednesday, January 26, 2011 5:26 PM
To: 'Ashraf Khan'; bldg-sim at lists.onebuilding.org
Subject: RE: [Bldg-sim] Warehouse ventilations to comply with ASHRAE 62.1

 

Ashraf,

 

It seems that all you need to do is demonstrate that your ventilation system
complies with Table 6-1.  Are you introducing at least .06 cfm/sq.ft of
outdoor air with the mechanical ventilation system?

 

If so, just document it!  If not, you're in trouble and will need to provide
a ventilation system.

 

 

 



 

The Building Performance Team
James V. Dirkes II, P.E., LEED AP
1631 Acacia Drive NW
Grand Rapids, MI 49504
616 450 8653

 

From: Ashraf Khan [mailto:ashraf at mecsd.com] 
Sent: Wednesday, January 26, 2011 8:15 AM
To: 'James V Dirkes II, PE'; bldg-sim at lists.onebuilding.org
Subject: RE: [Bldg-sim] Warehouse ventilations to comply with ASHRAE 62.1

 

Hello James,

 

I accept that ASHRAE 62.1 is concerned with people, the same we explained to
LEED Reviewer team, this is the comment we received, 

 

However, since the project uses ventilator fans it is considered a
mechanically ventilated space. Additionally, the LEED-NC v2.2 IEQp1 CIR
ruling dated 10/8/2008 states that unless the mechanically ventilated
warehouse has no human occupancy except for maintenance and repairs it must
meet the requirements of ASHRAE Standard 62.1-2004. The narrative states
that the warehouse will be occupied for the loading and unloading of goods;
therefore, the warehouse is regularly occupied. 

Provide calculations for the warehouse space demonstrating that the space
complies with the minimum requirements of ASHRAE Standard 62.1-2004.

 

I am not having any idea how to convince the team.

 

Thanks & Regards,

Ashraf

  _____  

From: James V Dirkes II, PE [mailto:jvd2pe at tds.net] 
Sent: Wednesday, January 26, 2011 3:46 PM
To: 'Ashraf Khan'; bldg-sim at lists.onebuilding.org
Subject: RE: [Bldg-sim] Warehouse ventilations to comply with ASHRAE 62.1

 

Ashraf,

 

ASHRAE 62.1 is concerned with people, who need ventilation (supply /
intake).  For typical buildings, you may not need separate exhaust fans,
because that amount can probably exfiltrate through cracks.  Supply and
exhaust fans can be used in tandem if the building is fairly tight (no
leaks).

 

Your MEP team's  5-8 air changes per hour is for cooling, not ventilation.
Any building with which has that much infiltration is closer to a tent than
a building! (It's not closed up.)

 

The Building Performance Team
James V. Dirkes II, P.E., LEED AP
1631 Acacia Drive NW
Grand Rapids, MI 49504
616 450 8653

 

From: bldg-sim-bounces at lists.onebuilding.org
[mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Ashraf Khan
Sent: Tuesday, January 25, 2011 11:55 PM
To: bldg-sim at lists.onebuilding.org
Subject: [Bldg-sim] Warehouse ventilations to comply with ASHRAE 62.1

 

We received a LEED review comment regarding Warehouse ventilation to comply
with ASHRAE 62.1-2004.

 

Generally depending on the warehouse storage, MEP team recommends 5-8 Air
Changes per Hour by thumb rule for exhaust and air intake is assumed by
infiltration by windows, open doors etc.. But this number I haven't find in
ASHRAE, please give me reference.

 

ASHRAE 62.1-2004, Table 6-1 for warehouse category says to have 0.06
cfm/ft2, is this number defines to intake or Exhaust? If it is exhaust, it
is too small as volume of warehouse will be high.

 

Please share your ideas to comply with the requirements.

 

Thanks & Regards,

Ashraf

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