Message Board Thread - "160x120 vs. 320x240 for moisture intrusion"

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160x120 vs. 320x240 for moisture intrusion moldsol 9/21/2006
Does anyone have an opinion on the neccessity of a higher resolution camera for building science applications; specific to moisture intrusion. Thanks in advance for your comments.
 
Re:160x120 vs. 320x240 for moisture intrusion JNTOOLS 9/27/2006
I have been using an E-65 for about 2 years now and it works very well for detecting moisture. With prices on cameras dropping you can’t go wrong with a higher resolution camera (EX320). But to answer your question it is not absolutely necessary. Here in Maryland I always verify any found anomalies with a non-penetrating moisture meter, especially in the winter time. I have seen strange insulation deficiencies in the winter that looked a lot like moisture. Also most building science thermographers look for the traditional cool spot anomalies that can indicate moisture. I have seen issues where the moisture showed up hot due to steam infiltration. A higher resolution camera would have been nice for this situation (more detail). The picture below shows what appears to be a summer time insulation deficiency, in fact it is steam entering from just above the rim joist and condensation on the inside of the gypsum below grade, the humidity inside the wall was so high it never had time to evaporate, thus never showed the cool anomaly. I would have like the EX320 for this situation.

J. Nachman
Building Science Thermographer
Longwave Inspection
 
Re:160x120 vs. 320x240 for moisture intrusion Avalon Inspection 9/28/2006
J.,
What is the source of this steam in the walls?
 
Re:160x120 vs. 320x240 for moisture intrusion JNTOOLS 9/29/2006
You may click or cut and paste the following link to open a PDF file that will show how the steam migrated into the residence.

http://www.longwaveis.com/PDF%20Files/Pad%20reconstruction.pdf
 
Re:160x120 vs. 320x240 for moisture intrusion San Patricio 1/4/2009
JNTOOLS wrote:
been using an E-65 for about 2 years now and it works very well for detecting moisture. With prices on cameras dropping you can’t go wrong with a higher resolution camera (EX320). But to answer your question it is not absolutely necessary. Here in Maryland I always verify any found anomalies with a non-penetrating moisture meter, especially in the winter time. I have seen strange insulation deficiencies in the winter that looked a lot like moisture. Also most building science thermographers look for the traditional cool spot anomalies that can indicate moisture. I have seen issues where the moisture showed up hot due to steam infiltration. A higher resolution camera would have been nice for this situation (more detail). The picture below shows what appears to be a summer time insulation deficiency, in fact it is steam entering from just above the rim joist and condensation on the inside of the gypsum below grade, the humidity inside the wall was so high it never had time to evaporate, thus never showed the cool anomaly. I would have like the EX320 for this situation.

J. Nachman
Building Science Thermographer
Longwave Inspection
Dice que estuvo utilizando durante dos años una E-65. Me gustaria saber en que tipo de aplicaciones la utilizó, y en cuales le encontro mayor aplicacion.
 
Re:160x120 vs. 320x240 for moisture intrusion Scott Wood Associates 2/16/2009
Resolution is only a piece of the specifications you should look at. Thermal sensitivity is a key consideration to building science thermography. I've used similar thermal images (same model) with different sensitivities, same resolution and have seen an obvious difference. For the lower resolution perform the inspections of the surface closer. In reality the thermal sensitivites of the higher resolution images is probably what you "see" more of allowing more patterns to appear.
 
Re:160x120 vs. 320x240 for moisture intrusion RobertC 2/16/2009
JNTOOLS wrote:
click or cut and paste the following link to open a PDF file that will show how the steam migrated into the residence.

http://www.longwaveis.com/PDF%20Files/Pad%20reconstruction.pdf
Bad Link.
 
Re:160x120 vs. 320x240 for moisture intrusion dmiller 2/5/2010
moldsol wrote:
yone have an opinion on the neccessity of a higher resolution camera for building science applications; specific to moisture intrusion. Thanks in advance for your comments.
I have a FLIR BX320 that I have used for about three years now. It is a great camera for moisture and mold.There is one often overlooked part of the decision to buy a thermal imager. This is the print quality for your reports. The 320x240 is well worth the added price for this feature alone. You can usually make a determination with a 160x120 with what you see, but it will not be easy to show your customer what you mean when you hand them the report. Most all energy audit reports require a great printer for the normal and thermal images. I have a good printer but I do have to adjust the image sometimes to get clarity for the reports even with the 320x240. This alone, in my opion,is enough to justify the 320x240. If you really want your reports to be top notch and not spend lots of time adjusting your images and printer to show the definition you and your customer desire, this is the way to go. Your reports will be look top notch!
Hope this helps.
 
Re:160x120 vs. 320x240 for moisture intrusion Tony C. 3/24/2010
I am in agreement with Scott, thermal sensitivity is the critical parameter related to the detection of moisture patterns. Spatial resolution can be compensated for by moving closer to the target object or surface. That said, if one has to get farther than 20 to 30 feet from the target surface to view the entire area of concern, then the 3 mrad imagers will certainly not pick up very detailed thermal patterns.

Some exterior work (roof inspections) do not require detailed imagery while others (moisture patterns due to diffuse air leakage) will require very detailed spatial resolution for verification. The same arguments can be stated for interior work. Moisture patterning can be a result of many causes. Increased spatial resolution provides you the option of better pattern verification and determination of the source of the moisture. Better temperature resolution provides you with increased limit state determination of the moisture patterning.
 
Re:160x120 vs. 320x240 for moisture intrusion Brad Carr 3/24/2010
Yesterday I was told by a Flir distributor that the BC provincial and Canadian federal governments require 320x240. Something to keep in mind if your going to take it to the next level.Up here we live in igloos. Our office buildings are made of caribou dung. Moisture intrusion can be a problem for both styles. Eh!
 
Re:160x120 vs. 320x240 for moisture intrusion Tony C. 3/29/2010
Brad:

Are you implying that Canadian office buildings are crappy?

That aside, what the Canadian federal thermographic assessment specifications state is that you can use whatever equipment you want but ensure that your spot size is sufficent for you to detect the minimum size of thermal signature relavant to your stated application.

For example if you need to determine the temperature of a wire coming out a fuse box, ensure that your spot size is three times smaller than the diameter of the wire to get a true temperture reading. If you are looking for air leakage patterns and the minimum size of opening you are interested in your cladding is 1/4", ensure that your spot size (1 pixel) is 1/4" for pattern detection purposes.

You can achieve these results easier with better resolution cameras or by getting much closer with lower resolution cameras and collecting exponentially greater numbers of images ans stitching them together to see the overall thermal patterns associated with larger target surfaces. The choice is yours but the limiting factor is always accurate spot size determination for the specific applications. Those are dictated within the specifications for each application.

In commercial projects and expecially in outdoor inspections, distance to target surfaces are much greater than in residential projects and greater resolution cameras make data collection faster.

Employing a 160x120 imagers will generally require you to take and process at least 4 time the number of images for the comparable work as if you used a 320 x240 imager. As long as the client gets comparable results, how they get it is up to the consulant.
 


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