Model External Shading Devices for LEED compliance

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Dear All,

I am new to Leed compliance simulations and I would like to know how to
model external shading devices in the proposed and baseline building.
Appendix G, Table G3.1 ? 5. Building Envelope, is clear about permanent
shading devices being allowed for the proposed building. But what about the
baseline building? Do you model the external shading devices in the baseline
building as well?

I?d appreciate any help on the matter.

Regards,

LIZZY GUHL

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Hi,

Appendix G allows you to claim credit for shading designs/devices.
Therefore, the baseline building is not required to have shading
devices/projections.

--

Regards
Hisham Ahmad

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Thanks for the fast reply. But it is possible, anyway, to model the baseline
building with external shading devices, right?

De: Hisham Ahmad [mailto:hisham at edsglobal.com]
Enviado el: Lunes, 22 de Marzo de 2010 7:58
Para: Lizzy Guhl
CC: bldg-sim at lists.onebuilding.org
Asunto: Re: [Bldg-sim] Model External Shading Devices for LEED compliance

Hi,

Appendix G allows you to claim credit for shading designs/devices.
Therefore, the baseline building is not required to have shading
devices/projections.

Dear All,

I am new to Leed compliance simulations and I would like to know how to
model external shading devices in the proposed and baseline building.
Appendix G, Table G3.1 ? 5. Building Envelope, is clear about permanent
shading devices being allowed for the proposed building. But what about the
baseline building? Do you model the external shading devices in the baseline
building as well?

I?d appreciate any help on the matter.

Regards,

LIZZY GUHL

Lizzy Guhl's picture
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Joined: 2011-10-02
Reputation: 0

Hi,

The baseline has to be modeled as per G3.1.5 which does not require shading
devices to be modeled. Why would you want to model them in the baseline ??
This will only compromise your energy savings.

--

Regards
Hisham Ahmad

Hisham Ahmad's picture
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Greetings-
Hisham makes a good point, why would you want to? But more specifically, Table G3.1 - 5 c states shading shall NOT be modeled, so there really is no debate.

Regards,
W. Peter Anderson, P.E

W. Peter Anderson's picture
Joined: 2011-09-30
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I think I can clarify the discussion.

First, baseline shading projections are NOT an option in 90.1-2007.

TG3.1, Baseline Building Performance, Section c. : "...All vertical glazing shall be assumed to be flush with the exterior wall, and no shading projections shall be modeled..."

To answer Hisham, the reason you might want to (even though you're not allowed to), is that in some instances permanent fenestration shades can be detrimental to your annual energy performance. Such shades almost always simultaneously help and hurt your HVAC systems - as they block solar load contributions in the summer (when you don't want them), but also in the winter (when you do). Glare issues aside, identical permanent shades/fins can easily be thermally helpful on one orientation but not another for the same project.

NICK CATON, E.I.T.

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Thank you Nick. You are completely right. I was asking this because the
solar load is needed in winter, especially in this case, because the heat
demand which is much bigger than the cold demand of the building. The fact
that I have to simulate the proposed building with external shading devices,
but the baseline building not, is giving me problems. Therefore my question.
Thanks again for the answers. Now I have it clear!

LIZZY GUHL

De: Nick Caton [mailto:ncaton at smithboucher.com]
Enviado el: Lunes, 22 de Marzo de 2010 10:52
Para: Hisham Ahmad; Lizzy Guhl
CC: bldg-sim at lists.onebuilding.org
Asunto: RE: [Bldg-sim] Model External Shading Devices for LEED compliance

I think I can clarify the discussion.

First, baseline shading projections are NOT an option in 90.1-2007.

TG3.1, Baseline Building Performance, Section c. : ?
All vertical glazing
shall be assumed to be flush with the exterior wall, and no shading
projections shall be modeled
?

To answer Hisham, the reason you might want to (even though you?re not
allowed to), is that in some instances permanent fenestration shades can be
detrimental to your annual energy performance. Such shades almost always
simultaneously help and hurt your HVAC systems ? as they block solar load
contributions in the summer (when you don?t want them), but also in the
winter (when you do). Glare issues aside, identical permanent shades/fins
can easily be thermally helpful on one orientation but not another for the
same project.

NICK CATON, E.I.T.

Lizzy Guhl's picture
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Joined: 2011-10-02
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