[Bldg-sim] Modelling 90.1 Baseline Envelope for Existing + Additions

[Santiago Velez]

Nick, thanks for the response. The answer is yes, I'am trying to make a
case for exceeding the 5% threshold for existing bit of the project, which
is not modified.
The project is a big existing conditioned warehouse, with lots of skylights
(18% of roof area), the new bit is an office building, with more skylights
(properly shaded this time!). I thought it would be fare to have a baseline
which maintains the existing bit exactly the same (18% skylights), and the
new addition according to Table G3.1.5 (5%). The global skylight area for
the whole project is *12%*, and this was reviewed.
The opposite happens for vertical fenestration, warehouse has almost no
windows, and the new office is fully glazed. With the same criteria,
existing stays the same, new is 40% max; then the proposed ends up with
global 32% WWR and baseline only 28%. This was reviewed as well.  Am
I explaining my self?

I thought this would be fair, and in fact it made so much sense I thought
it was the only possible interpretation... Its very good to remember one an
be *very* wrong.

So my approach should be:
- For vertical fenestration, 32% both baseline and proposed.
- For the skylights, I would multiple every skylight by  5/12 to get a
global 5% skylight.

 Hmmm....energy savings are going to plummet.
Thank you again Nick.

Santiago.


2013/11/4 Nick Caton <ncaton at smithboucher.com>

>  Proposed and Baseline areas/layouts matching works perfectly until you
> exceed either 40% for vertical or 5% for skylights.  See Table G3.1.5,
> baseline items c. and d.  This might be coincidence, but just to be cover
> all bases: 28% + 12% = 40% is an incorrect reading – the skylight and
> vertical fenestration thresholds are independent.
>
>
>
> I think you are to leave the vertical fenestrations alone (being under the
> 40% threshold) and you need to proportionally lower the area of the
> skylights in the baseline model to get back to 5%.  Proposed model needs to
> match actual design so it’s skylights remain the same.
>
>
>
> I’m not certain how or if the project being a major renovation has any
> bearing on the matter.
>
>
>
> Are you making the case that the existing skylights are envelope
> components not being touched, and so should remain equal in area between
> the models despite exceeding the 5% threshold?  Do you have additional new
> skylights complicating the matter?
>
>
>
> ~Nick
>
>
>
> [image: 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:* bldg-sim-bounces at lists.onebuilding.org [mailto:
> bldg-sim-bounces at lists.onebuilding.org] *On Behalf Of *Santiago Velez
> *Sent:* Monday, November 04, 2013 3:20 PM
> *To:* bldg-sim at lists.onebuilding.org
> *Subject:* [Bldg-sim] Modelling 90.1 Baseline Envelope for Existing +
> Additions
>
>
>   Dear forum users, I have modelled a project following Appendix G. and
> have received a review regarding my interpretation of % glazed area on the
> baseline.
>
> The project is a mayor renovations + Additions (existing conditioned
> warehouse + New office building attached). There were no modification on %
> area of vertical and horizontal glazing on the existing bit of the building.
>
> My approach was to model existing envelope, shape and fenestration,
> exactly the same in both proposed and baseline. The addition was modelled
> following the "maximum 40% for vertical fenestration and 5% for skylight"
> rule. The result of the whole building for baseline is, 28% vertically
> glazed and 12% of skylights (the existing bit was very different than 40%,
> and 5% respectively)
> The reviewer states that the end result for the baseline should still be
> 40% and 5%. It is not very clear to me how would I get there.. Do I have to
> make the existing fenestration proportionally smaller, just like I would do
> for the baseline of a completely new building?
>
> Thanks in advance.
>
> Santiago.
>
>
>
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