Latent Moisture - Part Two

David you are so correct the infrared camera spreads like wild fire I will be traveling 4 hours this Saturday to do a one year warranty scan. Received a call yesterday to do an inspection on a FSBO with basement water problems all of the Realtors in this town have stayed away from this home and did not want to list it because of the water problems.

Amen to that

Been using IR on all my inspection and not providing any information to the buyers or agents unless they pay for the service. I shot this in a condo. A common wall 2x4 second story interior. The adjacent unit is the same set up open living room. No adjacent sun light. No plumbing in the areas adjacent to this scan. No plumbing/vent pipes from the lower units. The wall had 2 outlets and 1 cable outlet.
Q. has anyone had any hot wires in walls that looks like this ?
or around the base boards?

room temp 68F.
lower center area on the wall 72F.
streak up the wall 71F.

Best

Ron

HPIM4797.JPG

IR_0023.jpg

Yes, but this does not look like that to me.

If a wire touches or almost touches the sheetrock you will get a definitive line. If it on the correct location of the stud, the stud bay will be warmer throughout.

The geometric pattern looks more like air movement to me.

I agree with David. Appears to be some sort of air infiltration. Was it warmer outside?

He posted that this is a second story so there is definitely a potential heat source below.
It appears that the image scale adjustment has been pushed to the limits so we are not talking about a whole lot of heat here.

I would change the palate to rainbow to see the direction of heat flow. Electrical wiring may show rather consistent across a wider source whereas air flow will graduate proportionately away from the source/point of entry.

David i reset the palette to rain for your rivew.

david i think you are correct. it look like a heat source from the lower unit. may have a small void or a nott in the wall plate…

have another look.

Thanks

Ron

IR_0015 NACHI.jpg

Large difference! No?

Now you can see the deficient insulation in the stud bay behind the Scale!

Another Tip: If you adjust the scale (move hi/lo towards each other) you can get all of the colors of the palette in the scan.

Ron,

Conductive heat flow travels from warm to cool (your room being the cooler).
The only way to accurately figure out your image is to see whats on the other side or try looking at the first floor unit if possible. If this is not possible, you may want to scan the area at different times during the day.

Three degrees isn’t a huge concern if your camera is set accurately (ie. correct emissivity value set in camera, and a calibration has been performed recently). If this hasn’t been done, you should be careful stating temperatures to clients. Here is an easy way to check your calibration of your camera in the field.
Ambient conditions of 67-75 F
Reference subject (Human face) should be calm
Set emissivity to .98
View subject’s face directly from approximately 3’
Use area- max (preferred) or spot feature
Measure temperature of tear duct area.
Radiometric reading s/b ~92-96 F

Manually adjusting your range and span is a good practice using auto can sometimes “mask” thermal variances. Changing palettes can be misleading, you can actually make things appear that really is not there.

I hope this helps you and maybe even some other readers.

Thanks.
Paul Ogletree, Instructor/Consultant
NACHI04052691
ASNT Level III Thermal/Infrared #125356
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This “calibration” test leaves a lot to be desired in my opinion!

Ambient conditions; (+/-) 10 degrees

Radiometric reading results; (+/-) 4 degrees

No reference to rh

"Approximately 3’ "; SSR compliant for a tear duct?

“should be calm”; how do we determine this? Ever study polygraph examinations! You can tell if someone is lying with IR by looking into their face!

I don’t think anyone here has a camera you can adjust the Range on. At any rate, the “Auto” setting does not change “Range” of the camera, it changes “Level & Span”.

Can you post an example of this?
Are you saying the palette is “making stuff up”?

I have always used melting ice to conduct a calibration check on my mid- temperature testing devices.

My camera manufacturer recommends the following testing procedure:
First, the calibration check should never be relied upon.
A field calibration check only addresses one temperature.
You must have a constant set up and procedure to do this properly.
Make sure nothing important changes between tests.
The target should be a metal container that produces high conductivity.
Make a high emissivity spot on the target large enough for the SSR/distance ratio.
The use of “melting ice” and water should be used to produce the desired test temperature (ice cubes are colder than 32°F, therefore the metal container).
An alternate is boiling water (at a rolling boil).

Most importantly, the conditions of this calibration test can be duplicated (which is an important scientific/legal requirement).

The materials required are more likely available at the home inspection site (metal cup, electricians tape, ice, water, known elevation). It is highly unlikely you will find a calm buyer, seller, real estate agent or home inspector at the home inspection site!

Dave,

Thank you for your response.

Your tear duct will be that temperature almost all of the time. I did not state that this method was the only way to do a calibration. You can also calibrate using a blackbody which in turn is a very expensive option. The main point I was trying to get across is - if emissivity is incorrect, the temperature reading is false.

Some thermographers do not have much experience performing building science work and possibly may not even know how emissivity effects temperature. A delta T will be different at an emissivity setting at .40 vice one at .98. Guessing at defects based on temperature without knowing what could be on the other side of a wall is not a good practice.

Palettes- you can do this with any image you have in your camera or hard drive with a thermal variance. I suggest you use one that will give you the best resolution for what you’re inspecting. Many palettes may not be suited for the type of inspection being performed. By the way, what is the image you posted in your last thread?

Thanks again.

Paul Ogletree, Instructor/Consultant
NACHI # 04052691
ASNT Level III Thermal/Infrared #125356
The Snell Group
P.O. Box 6
Montpelier, Vermont 05601-0006 USA
Tel. +1.802.229.9820 Fax +1.802.223.0460
pogletree@thesnellgroup.com
www.thesnellgroup.com

I just grabbed a scan from an open report I was working on and changed it to a rainbow hi res palette and tuned the span to make it look as colorful as I could, as an example.

I would post the digital, but it has personal property in it and I do not have permission to release this photo. Not much to see in an IR.

It is a wall/ceiling insulation deficiency.

This is very true, however the vast majority of materials in building science have a high emissivity. The scan in this thread has nothing with low emissivity except the outlet plate screws.

“This “calibration” test leaves a lot to be desired in my opinion!”

In fact I just got back from an International Standards Committee meeting with a team of medical folks (doctors and medical device experts) in which we wrote a draft standard for using thermography for screening people in a pandemic situation to see if they have a fever. The screening would be based on the temperature of the “inner canthus” (the tear duct area Paul mentioned). You may remember IR was widely used for this purpose a few years back in China during the SARS epidemic, but mostly it was used VERY poorly.

This simple “calibration check,” or really a functionality check as much as anything, is something we devised years ago to catch mistakes before they became costly—like an improperly set emissivity or background or, in some cases, a camera that simply is out of cal. It takes just a minute or two and quickly became an important part of what we consider a good practice.

I was very pleased to have the doctors in this meeting confirm that the surface temperature of the inner canthus varies very little, except perhaps in the wind or direct sun or with water splashed on the face. I was also surprised to have them validate that the offset between this surface temperature and “core” temperature was only a fraction of a degree-C, less than I’d always believed.

Anyway, thanks all for the good discussion.

Thermally yours,

John Snell
ASNT NDT Thermal/Infrared Level III #48166
Snell Infrared
800-636-9820
802-229-9820


http://www.IRTalk.com

That is very interesting to know!

This alone is too great a veriable for testing the operation of my equipment. How do we know the subject does not have something?

I don’t know of ice getting a fever. It can have salt in it though! :wink:

I would be interested in reviewing this standard.
Charlie B. and I do stuff on horses and i

That is very interesting to know!

This alone is too great a veriable for testing the operation of my equipment. How do we know the subject does not have something?

I don’t know of ice getting a fever. It can have salt in it though! :wink:

I would be interested in reviewing this standard.
Charlie B. and I do stuff on horses and it may prove safer than sticking stuff up the back side, if it applies to horses.

That is very interesting to know!

This alone is too great a veriable for testing the operation of my equipment. How do we know the subject does not have something?

I don’t know of ice getting a fever. It can have salt in it though! :wink:

I would be interested in reviewing this standard.
Charlie B. and I do stuff on horses and it may prove safer than sticking stuff up the back side!

That is very interesting to know!

This alone is too great a variable for testing the operation of my equipment. How do we know the subject does not have something?

I don’t know of ice getting a fever. It can have salt in it though! :wink:

I would be interested in reviewing this standard.
Charlie B. and I do stuff on horses and it may prove safer than sticking stuff up the back side, if it can be associated with a horse.

So is the temp reading 92-94 or body core temp (98.6f)?

http://en.wikipedia.org/wiki/Image:1911_Animal_heat.png

The duct may be close to body core, but it looks like this can not be considered “stable” .

Dave,

You obviously have a great knowledge of IR not only in building science but even in equine examinations. Impressive…

We love talking to people like yourself helping out however we can to give you data that may have never been discussed during your travels. Our staff has over 170 years IR experience and if you ever have any questions, please feel free to contact us to discuss any roadblocks you may discover.

Have a great weekend…

Paul Ogletree, Instructor/Consultant
NACHI # 04052691
ASNT Level III Thermal/Infrared #125356
The Snell Group
P.O. Box 6
Montpelier, Vermont 05601-0006 USA
Tel. +1.802.229.9820 Fax +1.802.223.0460
pogletree@thesnellgroup.com
www.thesnellgroup.com](http://www.thesnellgroup.com/)

John, what do you scan and what don’t you scan?
And if you don’t mind, what’s your work procedure, i.e., HVAC first then interior surfaces, electrical, etc.
Thanks,
Peter