Questions regarding baseline envelope

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So my proposed building is done. I'm working on my baseline building and a little confused on how to model the baseline building envelope/exterior.

This project is a renovation in climate zone 8. Most of the interior walls remain.

All the original roof structures remain , All exterior walls remain. No new exterior walls were constructed.

All exterior walls received a 5-1/2" EIFS system. All roof structures received 8-1/2" foam system buildup with new 2" klip-rib style metal decking.

The only thing that didn't remain on the envelope was the existing decking and all windows and doors got replaced.

The proposed building is modeled to reflect all this in equest - it is very close.

The building was a chapel and it will remain a chapel (non-residential/religious worship).

So here's the question...

In the baseline model, do I model the pre-existing configuration or do I change all the wall systems completely to match Appendix G, table 5.5-8?

Table 5.5-8 sais the exterior walls, above grade, should show steel framed.

Also, with regard to the roof, would the baseline roof need to be modeled as it was originally, taking into account the energy usage that the building would have had without the foam buildup we added.

Or would I need to just go off of table 5.5-8 again? - in my case the baseline would be "insulation entirely above deck" from that table.

OR should I just do parametric runs to tweak the baseline values down to be in compliance??

What would be an acceptable practice given the nature of the renovation and that the existing building remained?

Chris Baker
CCI CAD Drafter

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Chris Baker2's picture
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Hi Chris,

Your question doesn't state why you are doing the models. If you want to
show code, or LEED etc, compliance then you use Table 5.5.8. If you need to
show energy savings, for a utility program incentive or similar need, then
you would use existing conditions.

Shaun

sm
Shaun Martin's picture
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The model is for LEED approval.
The proposed building is done, the baseline building is in progress in equest.

To bring the building into compliance, however, what is the methodology most commonly used for the building envelope in particular when creating the baseline model?

For example, do I need to manually change all exterior walls to "steel framed" above grade walls to be in compliance with table 5.5-8?

Do all of these items need to be "manually" changed to the equivalent on table 5.5-8? Roof & Insulation, Above grade walls & insulation, Floors to steel joist, etc...

And if so, it would be faster to go back into the DD wizard for this, correct?

Thanks!

-Chris

Chris Baker2's picture
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Chris:

That is why I stay in the DD Wizard to building the ASHRAE 90.1 model;, so that all of what you speculate is the easier way comes true.

THEN, I can go to the Detail Edit and put in my lighting watts/sf, any process loads, and outside lights. Done with the BASE model.

NOW I make a copy of the Base, call it Proposed, then make all the changes to make the Proposed model.

In THIS way, I have my Base model NAILED. Most important to those LEED reviewers.

John R. Aulbach, PE

The model is for LEED approval.
The proposed building is done, the baseline building is in progress in equest.

To bring the building into compliance, however, what is the methodology most commonly used for the building envelope in particular when creating the baseline model?

For example, do I need to manually change all exterior walls to ?steel framed? above grade walls to be in compliance with table 5.5-8?

Do all of these items need to be ?manually? changed to the equivalent on table 5.5-8? Roof & Insulation, Above grade walls & insulation, Floors to steel joist, etc?

And if so, it would be faster to go back into the DD wizard for this, correct?

Thanks!

-Chris

From:Shaun Martin [mailto:smartin at shaunmartinconsulting.com]
Sent: Thursday, October 02, 2014 1:45 PM
To: Chris Baker; equest-users at lists.onebuilding.org
Subject: RE: [Equest-users] Questions regarding baseline envelope

Hi Chris,

Your question doesn?t state why you are doing the models. If you want to show code, or LEED etc, compliance then you use Table 5.5.8. If you need to show energy savings, for a utility program incentive or similar need, then you would use existing conditions.

Shaun

From:Equest-users [mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Chris Baker
Sent: Thursday, October 02, 2014 2:04 PM
To: equest-users at lists.onebuilding.org
Subject: [Equest-users] Questions regarding baseline envelope

So my proposed building is done. I?m working on my baseline building and a little confused on how to model the baseline building envelope/exterior.

This project is a renovation in climate zone 8. Most of the interior walls remain.

All the original roof structures remain , All exterior walls remain. No new exterior walls were constructed.

All exterior walls received a 5-1/2? EIFS system. All roof structures received 8-1/2? foam system buildup with new 2? klip-rib style metal decking.

The only thing that didn?t remain on the envelope was the existing decking and all windows and doors got replaced.

The proposed building is modeled to reflect all this in equest ? it is very close.

The building was a chapel and it will remain a chapel (non-residential/religious worship).

So here?s the question?

In the baseline model, do I model the pre-existing configuration or do I change all the wall systems completely to match Appendix G, table 5.5-8?

Table 5.5-8 sais the exterior walls, above grade, should show steel framed.

Also, with regard to the roof, would the baseline roof need to be modeled as it was originally, taking into account the energy usage that the building would have had without the foam buildup we added.

Or would I need to just go off of table 5.5-8 again? ? in my case the baseline would be ?insulation entirely above deck? from that table.

OR should I just do parametric runs to tweak the baseline values down to be in compliance??

What would be an acceptable practice given the nature of the renovation and that the existing building remained?

Chris Baker
CCI CAD Drafter

________________________________

CCI-Alliance Confidentiality notice: This message is intended only for the person to whom addressed in the text above and may contain privileged or confidential information. If you are not that person, any use of this message is prohibited. We request that you notify us by reply to this message, and then delete all copies of this message including any contained in your reply. Thank you.
________________________________
CCI-Alliance Confidentiality notice: This message is intended only for the person to whom addressed in the text above and may contain privileged or confidential information. If you are not that person, any use of this message is prohibited. We request that you notify us by reply to this message, and then delete all copies of this message including any contained in your reply. Thank you.

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John Aulbach's picture
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John,  I appreciate your input.

To do this model I went off of the DD wizard step by step instructions from the equest user manual - which was why I did the proposed model first.

If you do the proposed building first, and you are then able to run an error-free LEED compliance analysis, eQuest creates a baseline model for you with most of the inputs apparently already compliant with the Baseline parameters in Appendix G.

The baseline building created by eQuest appears to have alot of the proper systems and energy usage to be compliant.  air-side and water-side systems and specs and types appear to be compliant with baseline requirements even - at least so far.  I'm still going through everything to check.

It appears the building envelope still needs to be tweaked to match up with Table 5.5-8 from Appendix G.

In other words, it automatically creates a baseline for you, if you do the proposed building first.  I wasn't aware of this capability until just a few weeks ago.

Noone has talked about it much in the forums.  But it does still require some tweaking to be compliant.

However, It sounds like alot of people still do their baseline models completely manually and separate from the proposed model - sometimes before doing the proposed model even.

I guess I'm just trying to get a better understanding of common industry practice (with regards to the baseline model in particular).

I was originally under the assumption that the baseline would have to be created manually by copying the proposed model and updating all the parameters "manually" to match up with Appendix G - Similar to how you've described. 

So I'm a little bit confused now...

I'm now thinking it may be easier to apply my Baseline compliance inputs for building envelope in Detail Edit. 

If I open the Baseline Model and then go into Design Development Wizard it is likely going to be causing more problems when I go back to Detailed edit (I'm pretty sure alot of my inputs would be removed).

Thanks!

-Chris

Chris Baker2's picture
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Chris ?

Quick flag, if you?re modeling an existing building for LEED you likely will be permitted to model the existing building envelope constructions prior to the renovation as your baseline constructions.

Check out ASHRAE 90.1-2007/2010 Table G3.1 section 5 ? ?Envelope? ? baseline column, item ?f? ? ?for existing building envelopes, the baseline building design shall reflect existing conditions prior to any revisions that are part of the scope of work being evaluated.?

Aaron

Aaron Dahlstrom, PE, LEED? AP
In Posse ? A subsidiary of AKF| 1500 Walnut Street, Suite 1414, Philadelphia, PA 19102
d: 215-282-6753| m: 267-507-5470| In Posse: 215-282-6800| AKF: 212-354-5656
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Someone please correct me if I?m wrong but that has since been removed in later iterations of the ASHRAE standards

The Latest version of ASHRAE Appendix G is 2013, isn?t it?

G3.1, Section 5 ? baseline column item ?f? is now labeled ?Roof Solar Reflectance and Thermal Emittance? but doesn?t mention to use the existing construction as the baseline.

Keeping that in mind I went back to look in Section 5 to see if it is mentioned anywhere to use existing building envelope constructions as the baseline- when it comes to renovating existing buildings.

Section ?b? - Opaque Assemblies states that for new buildings, existing buildings, or additions they all need to conform with the following common, lightweight assembly types an shall match the appropriate assembly maximum U-factors in Tables 5.5-1 through 5.5-8 (we are in climate zone 8).

? Roofs ? Insulation entirely above deck

? Above-grade walls ? Steel framed

? Floors - Steel Joist

? Opaque door types shall match the proposed design and conform to the U-factor requirements from the same tables.

? Slab-on-grade floors shall match the F-factor for unheated slabs from the same tables.

At this point the project is near completion, actually.

I should note also that no new exterior walls were installed on this building, even the existing window sizing remained (just 1 for 1 swap).

The existing 8? CMU walls are from 1940 or so. The building is historic on Fort Wainwright, Army Base.

All exterior walls did receive new insulated wall furring on the inside and 5-1/2? EIFS buildup on the exterior. The roof received new 10? foam system buildup and new klip-rib style decking throughout.

Using the existing construction as the baseline building envelope would make sense to me because I would think it would give more accurate numbers but that isn?t what I?m seeing in Appendix G.

Chris Baker
CCI CAD Drafter

Chris Baker2's picture
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So what I ended up doing was this...

I found out we were applying for LEED NC 2009 cert - which only requires you to be compliant with ASHRAE 901 - 2007.  We didn't need to be compliant with the 2013 version of ASHRAE like I was originally told by our LEED green associate so I went back and reworked the baseline (I should mention that I caught this!).

I showed existing constructions prior to renovation just like it sais to do in section G3.1 (f) per Aaron Dahlstrom's post.

I also went back and recalculated the baseline plug loads, int/ext lighting, etc.. so that everything matched up with the 2007 numbers which are obviously less stringent than 2013.

-Chris

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