[Bldg-sim] Exterior Lighting Power Calculation for BuildingFacades

[Vikram Sami]

If you go by ASHRAE’s definitions, a non-tradable surface 

 

(LPD calculations for the following applications can be used only for the specific application and cannot be traded between surfaces or with other exterior lighting. The following allowances are in addition to any allowance otherwise permitted in the “Tradable Surfaces” section of this table.)

 

If I am interpreting this correctly, this means that for a building to comply, you have to comply for each tradable surface considered. So for example if you have two illuminated facades 100 feet long, and you had 2W/lft on one of them and 5.5w/lft on the other, you would be in violation of this because they are not tradable (even though the overall average is below 5w/lft).

I see nothing in appendix G about non-tradable surfaces. 

Vikram Sami, LEED AP 
Direct Phone 404-253-1466 | Direct Fax 404-253-1366 

LORD, AECK & SARGENT ARCHITECTURE



 

From: bldg-sim-bounces at lists.onebuilding.org [mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of weixiu kong
Sent: Friday, February 05, 2010 11:31 AM
To: Arvinder Dang; Robby Oylear; bldg-sim at lists.onebuilding.org
Subject: Re: [Bldg-sim] Exterior Lighting Power Calculation for BuildingFacades

 

Arvinder,

 

I got the interpretation from one of the LEED reviewers. And I think it 
agrees with how you show compliance for non-tradable surfaces.

 

Weixiu

 

________________________________

From: Arvinder Dang <Arvinder.Dang at som.com>
To: Robby Oylear <robbyo at rushingco.com>; "bldg-sim at lists.onebuilding.org" <bldg-sim at lists.onebuilding.org>
Sent: Fri, February 5, 2010 4:38:16 AM
Subject: Re: [Bldg-sim] Exterior Lighting Power Calculation for Building Facades

Weixiu

Are you sure about your interpretation of the non-tradable surfaces. If I understand correctly what you are saying is that even though my proposed design uses less lighting power compared to the baseline for the non-tradable surfaces I cannot get an benefit from those savings.

 

 My understanding was that total of tradable and nontradable should be less than the overall allowance +5% additional unrestricted allowance. 

Each category of tradable does not have to comply prescriptively and can be higher than base allowance in some cases and have increased savings in another. For example my overall lighting energy use can be higher for say parking area compared to the base allowance as long as I compensate that additional power by increased savings in another category say plaza area.

On the contrary one has to meet the prescriptive requirements for each category of non tradable surfaces and cannot exceed the allowance. Increased building façade lighting cannot be compensated by reduced gatehouse inspection station lighting.

 

Can someone please confirm this. 

In my model I have significant savings in non-tradable lighting and I have been modeling Ashrae allowance for non tradable area based on area being lit in base case and actually proposed design wattage and lighting power in the proposed case which is much lower. 

 

Thanks

 

ARVINDER DANG, LEED® AP

SUSTAINABILITY SPECIALIST   

 

SKIDMORE, OWINGS & MERRILL LLP 

224 SOUTH MICHIGAN

CHICAGO, IL 60604 

T: 312.360.4633  F: 312.360.4910 

ARVINDER.DANG at SOM.COM

 

 

SOM

 

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From: bldg-sim-bounces at lists.onebuilding.org [mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Robby Oylear
Sent: Friday, February 05, 2010 5:54 AM
To: bldg-sim at lists.onebuilding.org
Subject: Re: [Bldg-sim] Exterior Lighting Power Calculation for Building Facades

 

Weixiu,

 

The problem I am having is that I do not understand how to correctly calculate the baseline power allowance.  Part of the mandatory provisions of section 9.4.5 states that you cannot exceed the baseline exterior lighting power allowance with your proposed building.  By incorrectly calculating the baseline exterior lighting and showing this in my model the LEED reviewer has flagged my EAp2 credit for denial due to not complying with the mandatory provisions.

 

In short, I need to reply back with a corrected baseline lighting power allowance, which I am having trouble with due to the unclear definition of “illuminated wall”.

 

Robby Oylear, LEED® AP

Mechanical Engineer

direct: 206.788.4571

cell: 206.354.2721

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

 

From: bldg-sim-bounces at lists.onebuilding.org [mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of weixiu kong
Sent: Thursday, February 04, 2010 10:00 AM
To: Robby Oylear; bldg-sim at lists.onebuilding.org
Subject: Re: [Bldg-sim] Exterior Lighting Power Calculation for Building Facades

 

Robby,

 

My understanding is: since this is a non-tradable surface, base line and proposed design should be the same even though it is well below allowances.

 

Thanks,

 

Weixiu

 

________________________________

From: Robby Oylear <robbyo at rushingco.com>
To: bldg-sim at lists.onebuilding.org
Sent: Thu, February 4, 2010 10:21:28 AM
Subject: [Bldg-sim] Exterior Lighting Power Calculation for Building Facades

Can anyone with experience showing compliance with ASHRAE 90.1-2004 section 9.4.5 enlighten me as how the baseline calculation should be done? 

 

The confusion I’m having is with the definition of an illuminated wall or surface length when applying the 5.0 W/linear foot allowance for building façades.  How is the lineal footage of an illuminated wall determined?  

 

For example, if a 100’ wide wall has one exterior lighting fixture on it at the center, is the entire wall considered to be illuminated and thus the baseline lighting power allowance is 500W?  Or is there some method of determining the actual portion of the wall that is illuminated?

 

This came up on a LEED project where I had applied table 9.4.5 as conservatively as possible and only considered a portion of the wall to be illuminated at each fixture.  

 

Any help would be greatly appreciated.

 

Robby Oylear, LEED® AP

Mechanical Engineer

direct: 206.788.4571

cell: 206.354.2721

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

 

 

 

 

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