[Bldg-sim] Exterior Lighting Power Calculation for Building Facades

weixiu kong weixiuk at yahoo.com
Fri Feb 5 08:30:54 PST 2010


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, IL60604
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
 
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


      
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