[Bldg-sim] effective R-value cavity insulation

[mark dewsbury]

Dear Neeraj,

 

Building/solar orientation is a key factor. What was generally accepted to
be a relatively still air space was not. We have performed experiment twice
but a third time is needed to weed out some questions. I need to do some
more work in this area & publish our findings. 

 

Mark Dewsbury

Centre for Sustainable Architecture with Wood
School of Architecture
University of Tasmania
Locked Bag 1324
Launceston 7250
ph: 03 6324 4089
mob: 0417 290 807
fax: 03 6324 4088
e: mark.dewsbury at utas.edu.au

  _____  

From: Nearedge [mailto:near_ej at yahoo.com] 
Sent: Saturday, 18 September 2010 10:49 PM
To: bldg-sim at lists.onebuilding.org
Subject: Re: [Bldg-sim] effective R-value cavity insulation

 

The phrase "air currents in cavity spaces dependent on wall orientation"
suggests higher conductivity!
Though it'll be interesting to know more, perhaps changing solar radiation
on the facade with respect to time ?! . . . 
~Neeraj

Neeraj Kapoor
t: +91.99581.70018
e: neeraj[at]kalpakrit[dot]com
Kalpakrit Sustainable Environments Pvt. Ltd.
New Delhi, India

On 9/17/2010 10:49 AM, Carol Gardner wrote: 

Dramatically higher or lower?

On Thu, Sep 16, 2010 at 9:35 PM, mark dewsbury <Mark.Dewsbury at utas.edu.au>
wrote:

Dear Kevin,

 

I am sure this is going to be a hot topic very soon. 

In Australia, the ASHRAE & other values have been used for some years with
regard to cavity insulation values. This includes subfloors, walls, roof
spaces and spaces between roofing and sarking. We have conducted a few
preliminary studies with Engineering honours and Architecture PhD students
on actual buildings. They have all shown dramatically different results to
what was previously accepted. In the case of walls this has a dramatic
affect on the current practice of placing the insulation on the outside of
the cavity. 

 

In terms of the roof model we have documented variations up to 20 deg C
between DSP and observed results. Subfloors having variations but to a
lessor magnitude. 

 

We are hoping for some future moneys to go back to the fundamentals of the
physics models and modify them to relate to what is really occurring in
buildings. We have measured amazing horizontal and vertical air currents in
cavity spaces dependent on wall orientation.     

 

Mark Dewsbury

Centre for Sustainable Architecture with Wood
School of Architecture
University of Tasmania
Locked Bag 1324
Launceston 7250
ph: 03 6324 4089
mob: 0417 290 807
fax: 03 6324 4088
e: mark.dewsbury at utas.edu.au

  _____  

From: Kevin Kyte [mailto:KKyte at watts-ae.com] 
Sent: Friday, 10 September 2010 1:47 AM
To: mark dewsbury
Subject: RE: [Bldg-sim] effective R-value cavity insulation

 

This is what I received.

 

From: mark dewsbury [mailto:Mark.Dewsbury at utas.edu.au] 
Sent: Sunday, September 05, 2010 9:36 PM
To: Kevin Kyte
Subject: FW: [Bldg-sim] effective R-value cavity insulation

 

Dear Kevin,

 

Was there any feedback or comment from your question? 

I have done some preliminary studies with engineering honours students and
found dramatically different results to the theories. 

 

Mark Dewsbury

Centre for Sustainable Architecture with Wood
School of Architecture
University of Tasmania
Locked Bag 1324
Launceston 7250
ph: 03 6324 4089
mob: 0417 290 807
fax: 03 6324 4088
e: mark.dewsbury at utas.edu.au

  _____  

From: Kevin Kyte [mailto:KKyte at watts-ae.com] 
Sent: Sunday, 6 June 2010 2:13 AM
To: bldg-sim at lists.onebuilding.org
Subject: [Bldg-sim] effective R-value cavity insulation

 

I am curious what the relationship is between cavity depth, rated
insulation, and effective insulation in framed walls.  I am referencing the
ASHRAE 90.1 doc because it is really the only one I have on this subject.  I
have charted Table A9.2B and a logarithmic trendline appears to be a good
fit for extrapolating.  If anyone in academia, industry, or the societies
has more information on this subject I would certainly be grateful to
receive a good lead.  Thank you.

 

Kevin Kyte, LEED R AP

Watts Architecture & Engineering, P.C.

95 Perry Street, Suite 300

Buffalo, NY  14203

p:  716.206.5174

f.:  716.206.5199

e:   kkyte at watts-ae.com

http://www.watts-ae.com <http://www.watts-ae.com/> 

 

 

 


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-- 
Carol Gardner PE

 

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