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Beyond code compliance, but doable
This prerequisite is a big one, not only because it’s required for all projects, but also because it feeds directly into EAc1: Optimize Energy Performance, where about a fifth of the total available points in LEED are at stake. Master these minimum requirements, and you can use the same compliance path as in EAp2 to earning points.
You won’t earn the prerequisite by accident, though. Although “energy efficiency” is on everyone’s lips, the mandatory and performance-based requirements for EAp2 go beyond code compliance in most places. That said, there is nothing to stop you from meeting the requirements with a reasonable amount of effort, and the environmental benefits as well as the operational cost savings are significant.
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182 Comments
Baseline's chiller performance curve
Goodmorning,
i haven't understood how to consider the performance of the baseline's chiller: is it enough to consider a costant COP/IPLV ( tab. 6.8.1) or do i need a performance curve?
Thank you.
Hello Fabio,
I think it is enough.
90.1 requires that the software has the capability for the chiller to follow a performance curve, not that you need to enter one for the baseline. So you enter the COP/IPLV and the IPLV is the part-load efficiency based on the weighted average performance at various load capacities. Not certain without some more digging but I have assumed that the software creates a curve based on the COP and IPLV entered.
I'll check around and let you know if I am not accurate or someone else feel free to correct me.
Hello Marcus,
thanks a lot for your answer.
Have a nice day.
To be more accurate the software would typically use a default curve adjusted to the COP/IPLV.
Vestibules for conditioned buildings
We have a CS project, climatized, on which the client is insisting we should not have entrance vestibules, which to my understanding is mandatory under ASHRAE 90.1. Are there any acceptable alternative options for this requirement, like air curtains or other? We have already checked for exceptions but none of them apply for this project. The other idea is to turn the whole entrance lobby of the building as the vestibule of the entrance, and leave it naturally ventilated (project located in Guatemala City, with a very mild wather during all year).
What is Guatemala City's climate zoneOne of five climatically distinct areas, defined by long-term weather conditions which affect the heating and cooling loads in buildings. The zones were determined according to the 45-year average (1931-1975) of the annual heating and cooling degree-days (base 65 degrees Fahrenheit). An individual building was assigned to a climate zone according to the 45-year average annual degree-days for its National Oceanic and Atmospheric Administration (NOAA) Division.? Projects in climate zone 1 or 2 are not required to install vestibules (exception 5.4.3.4d).
Beyond the climate or revolving door options I am not aware of any other options. If you are unable to meet this requirement I would suggest submitting an interpretation to USGBC.
Exterior LIghting - ASHRAE 90.1 Mandatory Provisions
Dear all,
We know for the fact that for interior lighting:
"Trade-offs among building area types are permitted provided that the total installed interior lighting power does not exceed the interior lighting power allowanceInterior lighting power allowance is the maximum lighting power (in watts) allowed for the interior of a building.."
However, the requirement above is not explicitly stated for Exterior lighting, but section 9.4.5 discusses trade-offs and tradable surface.
My question is:
Can the installed exterior lighting power exceed the ASHRAE maximum allowance?
Thanks..
Exterior lighting is a mandatory provision so your project cannot exceed the ASHRAE maximum allowance.
Don't forget to include the 5% unrestricted allowance in your total allowable exterior lighting power. Be sure to include this in your Baseline model too.
Option 1: Without tenant, does not meet pre-requisite.
The client is developing without a tenant and is deferring major HVAC components to the tenant build-out (air handlers.) Without air handlers, the energy model does not meet pre-requisite with option 1. Project is too large to use other options. With no tenant in place, the client is not able to provide signed lease with language specific to performance. What are other options to acheive pre-requisite? This tenant signed lease does not seem to be in favor of developer clients, which was the purpose of CS to begin with?
I am not sure it needs to be a signed lease. Basically the developer needs to have in place a set of tenant guidelines that will be enforced once you have signed a lease. So for example, limit the tenants to something less than the 90.1 lighting power densities and you can claim credit for those savings.
You might also look at the adjustments you can make to the modeling results explained in this document -http://www.usgbc.org/ShowFile.aspx?DocumentID=10130
FTE
When can we use actual occupancy counts in energy modeling? Is it necessary to have a tenant lease to use the actual occupancy counts?
Yes, if you know the occupancy count then use that information instead of the defaults in the Reference Guide. I don't think you would have to have a signed lease to do so.
Mandatory provision in LEED CS
We actually construct a high rise office building with commercial area at the first level. One of our projected commercial tenant want to modify his frontage, that we previously made, by adding new entrance. Initially this area was served by one entrance. This entrance is in conformity with the mandatory provision of ashrae 90.1 2007 5.4.3.4 "Vestibule". His new entrance will not have vestibule and thus, will not be in conformity with ashrae mandatory provsion. It is a CS project. Is it of our responsability to impose to the futur tenant to respect the mandatory provisions of ashrae 90.1, and thus, imposed a vestibule?
Thank you.
Do any of the exceptions to this provision apply?
If not then it appears as if a vestibule would be required according to 90.1.
No exception can be applied. Thanks a lot for your answer.
Building Renovation
Advanced Energy Modeling for LEED states "Existing buildings with less than 50% renovation should not be rotated,...". How can one calculates renovation percentage of an existing building?
Existing building in general do not need to be rotated. The percentage of renovation should not matter.
If you could cite the page where this quote comes from that would be helpful. I searched the document using the quote above and it did not turn up.
Thanks Marcus, It is on page 7 under Baseline Case, Building Envelope column at the end of second paragraph.
The percentage of rennovation makes no sense at all. Perhaps it was attempting to refer to an addition that is greater than 50% of the exisiting triggering the rotation. I don't know of any requirement to do so but maybe it is in a LEED Interpretation.
Insulation requirements
Our LEED building consits on an 39 stories speculative office building that is on top of a 3 stories retail building. The retail will not apply for LEED certification.
The retail's roof will serve as a terrace for the speculative office building and will consit of a mixture of greenroof and hardscape.
¿Is there any insulation requirement for this slab? It will covered a retail space that will not be part of the LEED certification.
So far roof insulation requirements for the LEED building is observing R15 for the slab at level 39, but we want to confirm that the terrace is free of any insulation requirements.
Any comments will be appreciated.
Let me make sure I understand the question. Is it insulation between the top of the retail and the bottom of the office or is it insulation in a roof over the retail which serves as a terrace? If between the two spaces, then it would be considered a floor. If a roof, then a roof.
The insulation levels required are contained in Table 5.5-X in ASHRAE 90.1-2007 and vary by climate zoneOne of five climatically distinct areas, defined by long-term weather conditions which affect the heating and cooling loads in buildings. The zones were determined according to the 45-year average (1931-1975) of the annual heating and cooling degree-days (base 65 degrees Fahrenheit). An individual building was assigned to a climate zone according to the 45-year average annual degree-days for its National Oceanic and Atmospheric Administration (NOAA) Division..
The real question should be what is the appropiate level of insulation given the situation. If it is the roof of a retail facility it probably makes sense to insulate it in most climates.
The office building floor would only require insulation if it were unconditioned space below.
The retail roof/office building terrace should be insulated, but since the retail is not being certified, LEED will not care what you do there. It will not affect the results of the office building energy model.
Thank you so much.
Marcus, the retail's roof will serve as a terrace of the office building. I forgot to mention that the retaill surpass by a lot the office building perimeter (that's why its roof can serve as a terrace for the office building). It makes sense to insulate it, however it is not a requirement by law, so it might end up having no insulation at all by ownership requirements. Only LEED requirements (the prerrequisites) will be observed.
Thank you Christopher, it makes sense, i thought the same too, that LEED will not care whether the space below complies with ASHAREA (including obviously the insulation requirements).
I just wanted to double check.
Wow no applicable local or state energy code to require a minimum insulation level. Where is the project located?
Those of use involved with LEED do care about proper insulation levels but LEED may not require you to do anything about it. :-)
A potentially tricky part could be where you draw the line for your LEED project. If the terrace is in the LEED boundary, the horizontal placement of that line will need to be defined.
Thank you Marcus. The project will be built by phases, being phase 1 the office building (the one applying for LEED certification). The LEED boundary is drawn covering exactly that phase leaving the retail out of the LEED scope, but including the terrace within phase 1.
Process Costs Tables for C&S
Dear all,
I am modeling a C&S project (large shopping mall).
For the process loads, I am using:
- For the Core Areas: ASHRAE 90.1 User's Manual - Page G32 - Table G-B
- For the tenanted areas: LEED Reference Guide - Page 616 - Table 1 (CS Appendix 2)
1) Is this correct?
2) Is it normal to have my process costs at ~14% based on these tables? I will upload a detailed table demonstrating how I got this 14% based on the references I listed above.
Many thanks,
This approach meets the minimum requirements.
However for the core areas a better approach would be to work with the owner to determine the likely equipment being used in those areas and model what will be installated not some assumption from a book. This would give you an opportunity to evaluate what is being installed to see if there are opportunities to reduce energy usage.
This is the point of energy modeling. Not minimum compliance for LEED.
Upload EAp2-11
I'm using eQUEST for my project. I should upload certain documents for LEED review including "Input Summary". Do I have to create a summary report or there is a summary report within the eQEST sim file?
The input summary documents are spread throughout the .sim file. You are not required to submit any of them. If you do a good job of thoroughly completing the Section 1.4 table, this is sufficient. Provide the BEPS, BEPU and ES-D reports for both models.
diesel generator on-site
Hi everyone,
we are working on a project that produces its electricity on-site via diesel generators. The produced energy covers all energy consumption (heating is electric).
After 3-5 years the building will be connected to the public power supply, the diesel generators serve as emergeny power aggregates.
Since this is first time we are facing this I have some questions:
1. Should our LEED certification include the generators or are they negligible?
If they should be included:
2. Whats the correct way to determine energy rates?
Our oppinion : Proposed: Diesel Consumption * Diesel Prize * Efficiency of Generators
Baseline: Typical Prize for Electricity * Consumption
3. The heating system is electric, but the fuel is originally diesel, so should we pick the according BL system for electric?
4. Are there any mandatory provisions for the generators?
Thank you for any hints!
The project must include all energy consumed and associated with the project. The energy costs must be identical in both models see G2.4. I would determine the electric cost from the generators and use that in both models. I would look to the District Energy Systems guidance on USGBC's web site for guidance on the way to model this and the appropriate BL system. I don't think generators are covered by 90.1.
fan power calculation
Hi everyone,
I'm a bit confused about the correct way to calculate BL fan power.
The building has 6 stories and therefore 6x System 7 in the BL. In the Proposed there's just 1 CAV for the whole building.
The proposed CAV is fully ducted, has filters in supply ducts and exhaust ducts, a heat recovery device and sound attenuation. So theres a long list of applicable power drop adjustments.
My question is: Are these only applicable once or for every single BL system? So in my mind there are 3 possibilities:
1. Summarize all supply air flow rates -> calculate P_fan with all Pressure Drop Adjustments -> P_single_fan = P_fan * SA flow rate / summarized SA flow rates
2. Calculate P_fan individually with all Pressure Drop Adjustments
3. Calculate P_fan individually with Pressure Drop Adjustments, but count the "shared" Pressure Drop Adjustments like heat recovery device, sound attenuation only with 1/6.
Would be great to get some help here.
Your number 2 is closest to the correct approach.
Calculate P_fan individually based on supply cfm of each BL system with all Pressure Drop Adjustments, except no pressure drop adjustment should be taken for heat recovery where it is not required in the BL. See footnote to Table G3.1.2.9.
Interesting thread..
One question though:
You might have scenarios whereby you have 8 systems for the proposed (depending on the design) and 5 systems for the baseline (depending on the number of floors).
"Zone A" (served by HVAC System P1) in the proposed has a ducted return air, whereas "Zone B" (served by HVAC System P1) has a free return.
Both zones ended up in the Baseline being served under the same system B1 (same floor). Do we then have to adjust the baseline fan powers corrections of system B1 to accommodate for the ducted return, knowing that Zone 1 has a ducted return in the proposed but Zone 2 does not?
Thanks!
The pressure drop adjustment of 0.5 is only applied to the return CFM for zone A. It would not be applied to return CFM for zone B. Refer to Table 6.5.3.1.1A which defines CFMd.
Thanks Marcus,
However, my understanding was that I should enter the adjustment on the System level (AHU1.Air-handling units (AHUs) are mechanical indirect heating, ventilating, or air-conditioning systems in which the air is treated or handled by equipment located outside the rooms served, usually at a central location, and conveyed to and from the rooms by a fan and a system of distributing ducts. (NEEB, 1997 edition) 2.A type of heating and/or cooling distribution equipment that channels warm or cool air to different parts of a building. This process of channeling the conditioned air often involves drawing air over heating or cooling coils and forcing it from a central location through ducts or air-handling units. Air-handling units are hidden in the walls or ceilings, where they use steam or hot water to heat, or chilled water to cool the air inside the ductwork.) and not on the zone (I think that's the way it is done using eQUEST).
The information is entered at the system level.
The pressure drop is not entered directly in eQUEST. It is included in the calculation you do to determine the kW/cfm you enter in eQUEST. To calculate this value determine the total kW of all fans, then divide by the supply cfm and enter the kW per cfm in eQUEST at the system level.
There is a calculator in the Documentaion Toolkit related to Appendix G calculations for fan power. So for example, assume your system serving zones A and B has a total supply cfm of 1000 and the return cfm is 500 each. Enter 1000 in the column CFMs, the appropriate pressure drop in the PD column (0.5 for zone A and 0 for zone B) and the CFMd (500 each) for each zone in that column. The wattage should then be calculated as 1,208.3 watts. In eQUEST you enter 1.21 kW/1,000 cfm = 0.00121 kW/cfm at the system level.
ASHRAE 90.1 APPENDIX G Existing Building Model including shading
We are modelling a Major Renovation Project under the ASHRAE 90.1-2007 - APPENDIX G. The building existing conditions prior to this project renovation includes solar shading devices on all facades which greatly contributes to the building energy performance. The project team is currently evaluating at LEED point-of-view if the shading should be maintained or removed. It is not clear if the baseline building should consider the shading devices as in TABLE G3.1 - Baseline Building PerformanceBaseline building performance is the annual energy cost for a building design intended for use as a baseline for rating above standard design, as defined in ANSI/ASHRAE/IESNA Standard 90.12007, Informative Appendix G. states:
a. The building shall be modeled so that it does not shade itself; and also
f. For existing building envelope, the baseline building shall reflect existing conditions prior to any revisions that are part of the scope of work being evaluated.
I understand that the baseline model should reflect the solar shading contribution otherwise the benefit of a well-designed shading device would not be valued by ASHRAE standard.
Does anyone have an answer on this issue?
Technically it appears as if Table G3.1.5 Baseline (f) should be followed so there would be external shading in both models.
Our interpretation is based on the fact that G3.1.5 Baseline (a) does not apply to existing buildings and G3.1.5 Baseline (c) only appies to new buildings.
Thank you very much for your reply. That is also what we understand. A further thinking on this issue raised another question:
According to your interpretation, I understand the baseline model should be simulated only with its actual orientation and the 90, 180 and 270 degrees rotated models can de discarded from the simulation. Is that right?
Yes existing building do not have to be rotated for LEED.
Marcus,
Don't you think it is depend on the percentage of renovation of the existing building? "Advanced Energy Modeling for LEED" states "Existing buildings with less than 50% renovations do not have to be rotated". (Page 7)
That statement is not correct in my opinion. The Guide is trying to summarize 90.1 and in this case does so in a confusing manner. It does not even make any logical sense. The reason you rotate a building is to capture energy savings associated with orientation. Whether a building was 25% renovated or 100% renovated it would make no difference since an existing building can't be rotated.
I believe that in the case where there is new and existing building if more than 50% is new it would need to be rotated. I think this is what they were trying to get say.
I'm very glad that you mention that. Is there any way to request GBCI reviewer's point of view about that statement. I would like to know their opinion before submitting my LEED documents.
There are only two official means - a project specific CIRCredit Interpretation Ruling. Used by design team members experiencing difficulties in the application of a LEED prerequisite or credit to a project. Typically, difficulties arise when specific issues are not directly addressed by LEED information/guide or an Interpretation.
You can write to GBCI on their web site and ask but the response is not technically official.
Expect dealys in the response either way since Greenbuild is next week.
Doubt
Hi, I'm doing a LEED CS 2009 PRE-certification.
My question is:
In the "Upload L-4" section, which states:
Provide a detailed narrative describing the intended credit approach, including energy efficiency measures that will be incorporated intothe project and the anticipated energy savings.
What kind of documentation do I have to upload in detail?
Thank you very much
You should provide a narrative that includes a list of proposed energy conservation measures. In the pre-cert, you apply for a specific level of energy savings. You should explain why you think that level will be achieved. You might include the basis of design for the project, or any preliminary model results, although those items aren't strictly necessary.
Tenants HVAC System Type
We are modeling a Core & Shell office building where the HVAC system is in the tenant scope. we are only delivering chilled water and outdoor air to the tenant areas. We are specifying fan coil units system for tenant areas in the tenant design guidelines. My question is should we model HVAC type in the proposed design building as fan coil units or we should model it as the same type of the baseline building?
You can model the FCUs if there is a provision in the lease agreement which requires the tenant to connect to the CW system. The tenant guidelines are typically suggestions and are not mandatory. If not in the lease agreement, then the tenanat spaces would be modeled the same as the baseline.
Tenant build-out
We are in the process of modelling/simulating of office building in LEED C&S 2009 for EAp2 and EAc1 – Option 1. Building is divided into two parts: owner occupied space and offices for rent. Project scope includes core and shell (elevators, staircases, lobbies for all floors) and only build-out works for the owner occupied space. Offices for rent will be finished just before tenants move in (there are no internal partitions, toilets, tea kitchens …).
I have two questions regarding modelling:
1. Should we model offices for rent like large perimeter (15ft) + core zones or we should assume some fictive layouts for toilets, meeting rooms ...?
2. Is there any difference how to model this building in certification and precertification phase (in certification phase some of the tenant layouts may be available)?
1. You don't need to model a fictious layout. Depending upon the spaces model a core and perimeter and simply model exactly like the baseline. Think energy model, not loads.
2. Model what you know at the time. So yes if there is more information at certification than at precertification include it in your model.
LEED CS - EAp2 Existing equipment to remain
I have an existing 90,000 SF, 3-story office building in Massachusetts consisting of VAVVariable Air Volume (VAV) is an HVAC conservation feature that supplies varying quantities of conditioned (heated or cooled) air to different parts of a building according to the heating and cooling needs of those specific areas. boxes with electric reheat and rooftop units that also have electric heat. The scope of this project consists of replacing these rooftop units with gas fired DX units. The VAV boxes will remain as is and are outside of the project scope. Since we now have gas as a heating source, ASHRAE 90.1 requires that the baseline system consists of DX cooling and a hot water fossil fuel boiler. I do not see any exemption that would allow me to model the VAV boxes as is.
So with the baseline model using a fossil fuel boiler for reheat and the proposed model using the existing electric for reheat I am not able to meet this pre-requisite. Is there an exemption somewhere that I am missing?
You always model the Proposed (with a few minor exceptions) according to the design. If there is no design, match the Baseline. So while the VAVs are not changing they are still part fo the modeling scope for LEED.
Whether the Baseline system is fossil fuel or electric is determined by the predominant heating system. So in your renovated building is the gas in the roof tops or the electric reheat the predominant heating source? If gas than it looks like system 5 unless you can claim any of the exceptions in G3.1.1 to enable the use of a different system type.
Record Time for ASHRAE appx G Simulation?
What's your record time? What software did you use?
Longest or shortest?
In the old days you worked on your simulation during the day, hit simulate, went home since it took all night to do one run, and came back in the morning hoping it did not crash. Return to step one.
We have come a long way.
If we did not care about accuracy you could do one is a few hours. Trouble is we have a bit of a hang up about it so we take our time.
To more seriously answer your question our record shortest was probably around 16 hours. I will caveat that by saying that we never do a model just at the end so the model is created incrementally throughout the design process.
Compliance with Appendix G ASHRAE
We have a 14 storie-152600sft building which we are interested in certifying, however, there are 2 problems:
1. The client does not want a water treatment plant.
2. The client wants an air cooled HVAC system because the treated water generated by the building wouldn't meet the requirements for the HVAC system. In addition, mexican code does not allow the use of potable waterPotable water meets or exceeds EPA's drinking water quality standards and is approved for human consumption by the state or local authorities having jurisdiction; it may be supplied from wells or municipal water systems. for air cooling.
Could we still certify the building with air cooling and no treatment plant? Considering compliance with ASHRAE 90.1-2007, Appendix G is a prerequisite?
The building could still be certified. Nothing in 90.1 would force you to install a water cooled chiller.
You may be required to compare an air cooled chiller to a water cooled one depending upon building size. If that is the case you will have to find savings in other areas like the envelope and lighting.
Is your square footage gross or conditioned? Table G3.1.1A is based on conditioned space.
AREA CRITERIA
HI, I HAVE A PROJECT IN MEXICO CITY, AND THE OWNER DEFINE THE CRITERIA OF DONT USE TREATMENT PLANT AND USE AIR COOLED CHILLERS. THE CONDITIONED AREA IS 130,000 FT2 WITH 9 LEVELS OF OFFICE TOWER.
ACCORDING WITH APPENDIX G TABLE G3.1.1A AND G3.1.3.7, FOR NON RESIDENTIAL AND MORE THAN 5 FLOORS OR > 150,000 FT2. THE SYSTEM IN BASE BUILDING IS WATER COOLED CHILLERS.
IS CORRECT THIS CRITERIA FOR BASE BUILDING OR I CAN USE IN BASE BUILDING AIR COOLED CHILLERS?
THANKS AND REGARDS
Table G3.1.1A defines the baseline HVAC system. Based on your criteria you cannot use air cooled chillers. Make sure to check the exceptions in G3.1.1 to see if any apply.
EA Prereq 2 - precertification form
In the precertification form for EA Prereq 2 Minimum Energy Performance after selection of the appropriate compliance path (which in my case is Whole building energy simulation) there is another section with two options to choose from:
"Compliance with the prerequisite/credit requirements must be documented for the entire project building and associated grounds, including both the Core & Shell AND tenant-occupied spacesOccupied Spaces are defined as enclosed spaces that can accommodate human activities. Occupied spaces are further classified as regularly occupied or non-regularly occupied spaces based on the duration of the occupancy, individual or multi-occupant based on the quantity of occupants, and densely or non-densely occupied spaces based upon the concentration of occupants in the space.. Select one of the following:
1. In scope: The Core & Shell project scope will include the performance
improvements for the entire project building, including tenant-occupied
spaces.
2. Tenant Work: It is anticipated that there will be additional tenant work
beyond the Core & Shell project scope."
I'm not really sure which one to choose. Should the first one be selected if the data used in the simulation concerns only the scope of owner's work and the second point only if the owner requires from the future tenant to implement any energy efficient solution? Could someone explain to me when to use each of these options?
SIMULATION METHOD
HI, IM RICARDO GUEMEZ FROM MEXICO CITY, I AM IN THE PROCESS OF SIMULATING A WAREHOUSE FOR TENANT LEASING, THE OWNER IN ALL PROJECTS ONLY INCLUDE NATUARAL VENTILATION WITH IEQ-01 COMPLIANCE. ACCORDING WITH LEED AP THE PROJECT IS C&S. HOW CAN I SIMULATE THE PROJECT IN DESIGN BUILDING AND BASE BUILDING. Has anyone been in this similar situation?
Yes. We had a project in German with natural ventilation only. Basically what you can do is to set the fan power in your calculation to zero 0. This was a recommendation of one very helpful member of the GBCI's review team. But what you can't do without going through the trouble of exceptional calculations is to claim savings in cooling or heating because of the natural ventilation. Also be careful with how you account for cooling. You might have to assume cooling even if you don't have it everywhere. good luck.
ASHRAE Table 6.8.1 Centrifugal Chillers
Hi,
in the table 6.8.1J of ASHRAE 90.1 there is a "condenser Flow rate" parameter, expressed in gpm/ton.
My question is: to calculate this parameter do I have to use the nominal refrigeration power of my chiller or the power of the condenser only?
Thank you very much.
Regards
The "ton" part of the equation is for the nominal refrigeration provided by the chiller.
Outdoor Air Ventilation Rates to be Modeled
It is not clear to me how to model the "minimum outdoor air ventilation rates". If we intend to obtain the increased ventilation credit IEQc2, with at least a 30% increase above 62.1-2007, do these same rates need to be modeled in both the Baseline and Proposed cases? For example, lets say that a space will require 200 cfm of OA per 62.1-2007. To obtain IEQc2, we will provide 260 CFM of OA. Do we model this amount for both the proposed and baseline cases? If so, this "minimum outdoor air" as it is referred to in most areas of the LEED documents is not really the minimum as required by 62.1, but 30% higher, hence my confusion.
Energy Modeling
In a LEED CS 2009 building energy simulation we are modeling the building envelope to test performance (only the building envelope). It is a 10-story building with 2 glass façades with high-performance glass system and well-insulated opaque façades. The first 2 stories will be owner-occupied and the rest will be rented. But the model so far is failing because the slabs (levels 4-10) are being modeled as they will be left by the developer (concrete slabs) without considering that in the future the tenants will build their fit-out (including false ceilings, flooring systems, etc.), which will add insulation value to the slabs; at the end, this is likely to make our project pass the building envelope test.
Since the fit-outs are not part of the developer’s scope, but will be built by the tenants, would this be acceptable in the energy simulation model with the appropriate narratives?
The slabs would not be insulated by a drop ceiling or floor finish. They would be insulated as a part of the exterior wall assembly. So is the issue between floors or the slab conducting to the exterior? If between floors one would assume the tenant spaces are fully conditioned so there would be no losses between those floors unless there were different conditions.
If you model the building as required from an energy perspective it is fully occupied and fitted out with equipment. You don't model part of the building as unoccupied and unconditioned.
Building Slabs: not in Developer's scope of work
In a LEED CS 2009 building energy simulation: we are modeling the building envelope to test performance (only the building envelope). It is a 10-story building with 2 glass façades with high-performance glass system and well-insulated opaque façades. The first 2 stories will be owner-occupied and the rest will be rented. But the model so far is failing, because the slabs (levels 4-10) are being modeled as they will be left by the developer (concrete slabs), without considering that in the future the tenants will build their fit-out, including false ceilings, flooring systems, etc., which will add insulation value to the slabs and make them acceptable. As the fit-out is not part of the developer’s scope of work but will be built by the tenants, is this acceptable in the energy simulation model with the appropriate narratives:
“In Core & Shell buildings, not all the components addressed by ASHRAE 90.1-2007 may be designed or defined. For these types of projects, show compliance for the scope of work that is controlled by the core and shell project team. For example, if there is no lighting scope of work in the Core & Shell, the team need not demonstrate compliance with the lighting standard but must show compliance with other provisions.” (LEED GBDC Reference Guide, EApr2 pg. 246)
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