[Equest-users] Building area method ASHRAE 90.1

[Patrick J. O'Leary, Jr.]

and maria is correct "Space by space method does allow trade-offs 
between spaces, because it compares the total specified lighting wattage 
for the entire building to the _sum_ of space-by-space allowances (see 
section 9.6.1 d)."  this is also noted in the user's manual in example 9-p.

On 5/23/12 2:09 PM, Maria Karpman wrote:
>
> Patrick,
>
> I agree with Bill that it is irrelevant for energy modeler whether 
> space-by-space or building area method was used to document compliance 
> of the lighting design with the energy code (see his discussion on 
> mandatory versus prescriptive requirements of 90.1). As a side note, 
> when compliance with energy code is documented using prescriptive path 
> (for example via ComCheck), exceeding LPD allowances for individual 
> space types does not mean that project fails to comply using 
> space-by-space method, as you seem to imply below. Space by space 
> method does allow trade-offs between spaces, because it compares the 
> total specified lighting wattage for the entire building to the _sum_ 
> of space-by-space allowances (see section 9.6.1 d). I also agree with 
> Bill that space-by-space method is the only way to provide meaningful 
> feedback to the design team. It also helps to catch issues with LPD 
> calculations, such as treating partial or temporary lighting in core 
> and shell spaces as complete lighting system, or failing to include 
> unspecified plug-in lighting in hotels into LPD calculations. 
> Space-by-space method also comes with a carrot of increased lighting 
> allowances as described in 9.6.2.
>
> Maria
>
> *From:*equest-users-bounces at lists.onebuilding.org 
> [mailto:equest-users-bounces at lists.onebuilding.org] *On Behalf Of 
> *Patrick J. O'Leary, Jr.
> *Sent:* Wednesday, May 23, 2012 3:41 PM
> *To:* Bishop, Bill
> *Cc:* eQuest Users; Oscar B.
> *Subject:* Re: [Equest-users] Building area method ASHRAE 90.1
>
> referencing this comment:  "The only obvious case for using the 
> Building Area Method to determine modeled LPD is the case that Nick 
> mentioned where lighting neither exists nor is specified."
>
> or when the lighting designer/electrical engineer has higher lighting 
> densities that exceed one (or more) of the space-by-space maximum 
> allowable lpds but compensates for it by having lower lpds in other 
> spaces such that the whole building lpd does not exceed the maximum 
> allowable by the whole building method.
>
>
>
>
> On 5/23/12 7:45 AM, Bishop, Bill wrote:
>
> Building Area and Space-by-Space are not methods for designing 
> lighting systems. They are prescriptive requirements for demonstrating 
> lighting energy compliance in 90.1. The LPD allowances in Tables 9.5.1 
> and 9.6.1 do not need to be complied with if using energy modeling to 
> demonstrate compliance for 90.1 and for LEED. (Only the Mandatory 
> Provisions of 9.4 need to be met for the lighting design.) Energy 
> modelers only need to know the lighting power and space use 
> categorizations of the design as shown on the drawings (along with 
> schedules and controls), not the process used to design it (which 
> typically considers light levels in footcandles or lux).
>
> I think that /if/ a lighting system has been designed, a strong 
> argument can be made that the space-by-space method needs to be used 
> in both the proposed and baseline cases, and that lighting power needs 
> to be entered individually for each space/zone.
>
>                 "If construction documents are complete, the proposed 
> building lighting system power is modeled as shown on the design 
> documents." (ASHRAE 90.1 User's Manual, p. G-17)
>
> "The LPD for the proposed design is taken from the design documents 
> for the building. The LPD specified in the models must correspond to 
> the spaces within each thermal block." (ASHRAE 90.1 User's Manual, p. 
> 11-14 and also p. G-18)
>
> The only obvious case for using the Building Area Method to determine 
> modeled LPD is the case that Nick mentioned where lighting neither 
> exists nor is specified.
>
> As Maria Karpman, Nick and Patrick have mentioned, you are likely to 
> show higher energy savings using the Space-by-Space method. Beyond 
> that, using Space-by-Space allows you to give valuable feedback to the 
> design team, which I would argue is a responsibility of energy 
> modelers. It is routine for me to point out areas of potential 
> improvement of the lighting design in every project I model, based on 
> the allowances in Table 9.6.1. "Yes, Ms. Architect, that is a lovely 
> looking light fixture, but 2.6 W/ft2 of lounge lighting is more than 
> twice the baseline allowance." I don't know how you give helpful 
> feedback if you are just comparing two building-averaged lighting 
> power densities.
>
> Regards,
>
> Bill
>
> ** <mailto:wbishop at pathfinder-ea.com>
>
> *From:*equest-users-bounces at lists.onebuilding.org 
> <mailto:equest-users-bounces at lists.onebuilding.org> 
> [mailto:equest-users-bounces at lists.onebuilding.org] *On Behalf Of 
> *Patrick J. O'Leary, Jr.
> *Sent:* Tuesday, May 22, 2012 7:28 PM
> *To:* Nick Caton
> *Cc:* eQuest Users; Oscar B.
> *Subject:* Re: [Equest-users] Building area method ASHRAE 90.1
>
> actually nick, i agree with you.  since i don't design lighting 
> systems i always ask the lighting designer which method they're using 
> before i start building a model.  almost all of the lighting 
> designer's i've worked with use the whole building area method, though 
> as you point out the space-by-space method can actually do a bit 
> better for energy savings.
>
> my point is that there isn't a mandate to use either the 
> space-by-space or whole building area method and there is no 
> justification as far as 90.1-200x is concerned for a usgbc reviewer to 
> claim that the space-by-space method be used.  the requirement per 
> 90.1 is that the method be consistent in both the proposed and 
> baseline models.  space-by-space in both or whole building in both.  
> this is what i've had to point out to reviewer's when i've received 
> comments.  just quote chapter & verse to show that the method 
> (space-by-space or whole building) used meets the 90.1 app g 
> requirement and is applied the same in both models.
>
> as far as comcheck, comcheck reports from lighting designers are only 
> as good as the individual filling them out.  i've had lighting 
> designers (with all of their extra letters including pe after their 
> names) fill them out incorrectly.  i.e. not having all the lighting 
> fixtures the same in drawing schedules as input into comcheck, not 
> having same number of fixtures in drawings and in comcheck, not having 
> the same floor areas in drawings and in comcheck, and worst of all, 
> not using the same methodology in comcheck that they've used to design 
> the lighting system in the first place.   yes, i've seen comcheck 
> reports that indicate space-by-space when the lighting designer has 
> told me whole building method.  and vice versa.  so i always end up 
> confirming my lighting take-offs (from the lighting plans) and 
> methodology with the lighting designer/electrical engineer and their 
> comcheck report.
>
> On 5/22/12 3:58 PM, Nick Caton wrote:
>
> Hmm, I think I'm on the fence here.
>
>
> My practice is identical to Vikram's description for both energy 
> modeling and when documenting compliance for my lighting designs:  
> Choose whatever method you wish, but always use the same approach for 
> baseline and proposed.  This is pretty clear outside of Appendix G, 
> when documenting compliance.  For modeling, I don't use either 
> approach predominantly -- it depends on the project.
>
> Since Patrick is pushing one side, I'll play devil's advocate =):  I 
> can affirm I've used "whole building" averaged LPD in proposed models 
> for successful LEED submission without incident multiple times, 
> documenting that clearly along the way, but I was using "whole 
> building" for the baseline as well in each instance.  I do not 
> personally read 90.1 or LEED to explicitly require LPD be defined with 
> space-by-space for a proposed model.  Patrick, I just checked each of 
> your citations and the only specific call for either method is when 
> the lighting system has not been designed, in which case the whole 
> building approach is prescribed.  Keep in mind both methods should sum 
> to the same total installed watts for the proposed design.
>
> Back to the neutral perspective:  I'll emphasis I do use both approaches.
>
> To Oscar's case:  My general experience has been the whole building 
> method is less generous in net allowable watts when you run the 
> numbers both ways.  In other words, you may stand to earn more LEED 
> points by making your baseline more detailed, using space by space.  
> My suggestion for Oscar is to simply go with the reviewer's flow and 
> possibly walk away with another point tucked under your arm... it'll 
> probably be a similar amount of effort on your part relative to 
> composing an opposing response, and you won't have to worry about the 
> reviewer disagreeing =).
>
> I agree space-by-space is 'better' for that reason alone -- if 
> different at all, it tends to yield a better performance rating.  I 
> will acknowledge space-by-space is also "more accurate," notably so if 
> you're simultaneously defining distinct & accurate lighting schedules 
> space-by-space, but whether the corresponding additional time 
> investment and resulting "accuracy boost" are advantageous for a given 
> LEED model is a toss-up.  I personally feel the role accuracy plays in 
> a LEED model is often overblown to a point of silliness, but that's a 
> personal call we each need to make and a whole 'nother discussion.
>
> Hot related tip:  energy modelers and MEP designers alike need to be 
> aware of COMcheck.  I find it an invaluable time saver for speeding up 
> takeoffs for whole bldg & space by space calcs, and it's only as 
> costly as eQuest.
>
> ~Nick
>
> cid:489575314 at 22072009-0ABB
>
> **
>
> *NICK CATON, P.E.*
>
> SENIOR ENGINEER
>
> Smith & Boucher Engineers
>
> 25501 west valley parkway, suite 200
>
> olathe, ks 66061
>
> direct 913.344.0036
>
> fax 913.345.0617
>
> www.smithboucher.com__
>
> *From:*equest-users-bounces at lists.onebuilding.org 
> <mailto:equest-users-bounces at lists.onebuilding.org> 
> [mailto:equest-users-bounces at lists.onebuilding.org] *On Behalf Of 
> *Patrick J. O'Leary, Jr.
> *Sent:* Tuesday, May 22, 2012 4:49 PM
> *To:* Sami, Vikram
> *Cc:* eQuest Users; Oscar B.
> *Subject:* Re: [Equest-users] Building area method ASHRAE 90.1
>
> as long as a lighting system has been designed:
>
> according to ashrae/appendix g the uniform/whole building method 
> applies a uniform lpd to the BASELINE building only while the PROPOSED 
> uses what is designed - so long as the design is based on the whole 
> building area method.  the lpd of the PROPOSED design should not be 
> applied uniformly to the PROPOSED building simulation.
>
> see appendix g, table g3.1, section 6 lighting, subsection b, page 173 
> (2004), page 179 (2007).  user's manual pages g-17/18 (2004 & 2007)
>
> i would suggest to quote table g3.1 when replying to the reviewer's 
> comment.  i have had reviewer's tell me i have to use the 
> space-by-space method in a simulation for both proposed and baseline 
> buildings.  this is not correct.  what is correct is that the 
> simulation reflect the methodology used by the lighting designer.  if 
> the lighting design is based on the whole building method then the 
> whole building method maximum lpd is used in the BASELINE building.  
> if the design is based on the space-by-space method then the 
> space-by-space maximum lpd for each space type is used in the BASELINE 
> building.  in either case the PROPOSED building should reflect what is 
> designed.  by 'what is designed' i mean look at the lighting plans, 
> lighting schedules, and enter the lpd for each space/zone (thermal 
> block) based on the number of fixtures, watts per fixture, and square 
> feet of space.
>
>
>
> On 5/22/12 2:15 PM, Sami, Vikram wrote:
>
> The building area method applies a uniform LPD to the entire building. 
> If you do that in your baseline, you need to apply a uniform LPD to 
> you proposed building too.
>
> In general, I don't recommend using the building are method -- the 
> space by space method is a better approach.
>
> **
>
> *Vikram Sami*, LEED AP BD+C
>
> Sustainable Design Analyst
>
> 1315 Peachtree St. NE, Atlanta, GA 30309
>
> t: 404-443-7462    f: 404.892.5823     e: vikram.sami at perkinswill.com 
> <mailto:vikram.sami at perkinswill.com> www.perkinswill.com 
> <http://www.perkinswill.com/>
>
> *Perkins+Will.*Ideas + buildings that honor the broader goals of society
>
> *From:*equest-users-bounces at lists.onebuilding.org 
> <mailto:equest-users-bounces at lists.onebuilding.org> 
> [mailto:equest-users-bounces at lists.onebuilding.org] *On Behalf Of 
> *Oscar B.
> *Sent:* Tuesday, May 22, 2012 4:38 PM
> *To:* eQuest Users
> *Subject:* [Equest-users] Building area method ASHRAE 90.1
>
> How does the building area method work?
>
> I just got a comment from the review team for a project pursuing LEED 
> certification.
>
> I used the building area method for the baseline case and in the 
> proposed case I put the LPD from the lighting design. However they 
> told me that the same method has to be used in both cases.
>
> Any help would be appreciate.
>
>
>
>
>
>
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