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Building facade temperature appears cooler then the atmospheric temperature: WHY?
12-18-2013, 10:33 AM
Post: #1
Building facade temperature appears cooler then the atmospheric temperature: WHY?
Hi. I´ve scanned a house and the result is bit confusing. The temperature of the facade appears to be cooler then the atmospheric temperature ( 2°C) Ideally the temperature on the facade should be similar. Usually the trouble is when the facade appears to be warmer then its environment. Here the temperature on the facade is -3.2 °C whilst the atmospheric temperaure was +1°C. (- 2.2 °C Facade / 1.5 °C Atm. Temp for second image) Was any parameter set up wrong?


Conditions: Clear sky / Atmospheric temperature +1 °C / no rain,snow,wind etc.
I would appreciate Your feedback and response.


Thank You.

       

David Marek
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12-18-2013, 10:55 AM
Post: #2
RE: Building facade temperature appears cooler then the atmospheric temperatuWHY?
Shooting from the grround upward liike this you're going to get a little reflection from the cold sky. I would be difficult to get an accurate temp. from this angle.

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12-18-2013, 02:53 PM (This post was last modified: 12-18-2013 02:53 PM by acardoso.)
Post: #3
RE: Building facade temperature appears cooler then the atmospheric temperatuWHY?
How did you evaluate Trefl?
How did you evaluate emissivity?
Regarding ambient temperature, consider building yourself a black-body of ambient temperature. Otherwise, you can have errors that make no sense.
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António
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12-19-2013, 08:13 AM (This post was last modified: 12-19-2013 08:28 AM by Wieslaw.)
Post: #4
RE: Building facade temperature appears cooler then the atmospheric temperatuWHY?
    I bet the "Odr.T" should be -40C at this conditions (you might consider measure it roughly on Alu foil hung in direction of interest, with e=1 temp. settled..) And I'd set emissivity at 0.91 probably..

Despite of that, absolute temp reading is no matter in building envelope investigation, I mean. More interesting should be seen if you lower the temp. span , say to 0..10C.

Even more, played a bit with your pics and seems the second shows some moist in the wall - it might be why some parts of wall ale colder then air...

(Just IMHO)

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12-19-2013, 09:08 AM
Post: #5
RE: Building facade temperature appears cooler then the atmospheric temperature
As the others have said, it's likely that what you are seeing is the impact of a cold sky reflection. That will impact any surface viewed at an upward angle that has emissivity less than 1, in other words, any surface.

One other, less likely, possibility is that the air has recently warmed up from a temperature lower than that of the wall, without the wall's having caught up to it. I say this because I note that your time stamps are about 8AM.
JK

Jack Kleinfeld, P.E.
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01-02-2014, 11:43 AM
Post: #6
RE: Building facade temperature appears cooler then the atmospheric temperatuWHY?
All the best in 2014 and many thanks for Your reply,

At the moment I´m proceeding other images of this house. You say, that there may be some moisture in the facade as it appears colder? When scanning flat roofs it is common that damaged areas appear to be warmer (as wet insulation retains moisture) then the rest of the roof. Is it because flat roof inspections are usually done during summer months? Wet parts of the facade during winter then appear cooler as infiltrated water has lower temp then the rest insulated facade?

I´m quite new in thermography, my main occupation is architecture, so I appreciate Your advice.

Best regards.

David M.
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01-02-2014, 04:02 PM
Post: #7
RE: Building facade temperature
Roofs are normally checked a little after sun set and the wet spots hold the heat longer than dry roofing and are warmer. If you were to shoot the roof in the morning a little after the sun hits it they will be cooler as it takes the sun longer to warm the wet spots. You don't say on what side of the building this image is or the time of day. Without the solar heating wet spots will be cooler due to evaporation. If your image was taken in the morning on the sunny side it also will be cooler until the sun heats it.
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01-04-2014, 12:44 PM (This post was last modified: 01-04-2014 02:46 PM by David Marek.)
Post: #8
Building facade temperature appears cooler then the atmospheric temperature
Hello to All,

I´ve proceeded the IR images playing around a little with the input data but the result is still bit unclear to me. I would appreciate Your opinion on this subject. For each IR image I´ve uploaded:

1) PROTOCOL LIST with data edited by me in PDF.
2) JPG image with camera direction and facade point of the compass: these images were taken on a different day thus are only descriptive and do not corespond with IR images.
3) IR image



.pdf  01.pdf (Size: 801.04 KB / Downloads: 12)         JPG+PROTOCOL LIST+IR image 01

Conditions:

Morning before the sunrise
Air temp: 0.3°C
Refl. temp: -50°C due to the clear sky
Emissivity set up for various measured points on facade: 0.88 ( facade mineral insulation covered with plaster base+ plaster / final facade finish not done yet)
No wind, snow,rain etc.
Interior of the building was heated up to 20°C about 20 hours before the IR scanning

TARGET:

To reveal if the mineral insulation was layered properly without any gaps or other procedure failures like injecting glue in insulation seams etc. Thermal insulation+plaster base+plaster is on the building already for some time (rain, wind etc) and the IR scanning was taken before the facade is covered with final finish to avoid cracks etc. on the final finish facade layer.

Note: steel window supports below windows are still not covered with thermal insulation and therefore they appear as thermal bridge.

The building is still under construction and due to the weather conditions the drying process of the building is slowed down and materials (concrete etc) still contain moisture. Heating system and Ventilation with heat recuperation was set up only about 1.5 months ago.


.pdf  02.pdf (Size: 566.61 KB / Downloads: 9)         JPG+PROTOCOL LIST+IR image 02

Conditions:

Morning before the sunrise
Air temp: -0.2°C
Refl. temp: -50°C due to the clear sky
Emissivity set up for various measured points on facade: 0.88 ( facade mineral insulation covered with plaster base+ plaster / final facade finish not done yet)
No wind, snow,rain etc.
Interior of the building was heated up to 20°C about 20 hours before the IR scanning

TARGET:

To reveal if the mineral insulation was layered properly without any gaps or other procedure failures like injecting glue in insulation seams etc. Thermal insulation+plaster base+plaster is on the building already for some time (rain, wind etc) and the IR scanning was taken before the facade is covered with final finish to avoid cracks etc. on the final finish facade layer.

Note: steel window supports below windows are still not covered with thermal insulation and therefore they appear as thermal bridge.

The building is still under construction and due to the weather conditions the drying process of the building is slowed down and materials (concrete etc) still contain moisture. Heating system and Ventilation with heat recuperation was set up only about 1.5 months ago.

       
.pdf  03.pdf (Size: 1.37 MB / Downloads: 9) JPG+PROTOCOL LIST+IR image 03

Conditions:

Morning before the sunrise
Air temp: 0.9°C
Refl. temp: -50°C due to the clear sky
Emissivity set up for various measured points on facade: 0.90 ( facade above windows covered only with extruded polystyren thermal insulation )
No wind, snow,rain etc.
Interior of the building was heated up to 20°C about 20 hours before the IR scanning

TARGET:

To reveal if the mineral insulation was layered properly without any gaps or other procedure failures like injecting glue in insulation seams etc. Thermal insulation+plaster base+plaster is on the building already for some time (rain, wind etc) and the IR scanning was taken before the facade is covered with final finish to avoid cracks etc. on the final finish facade layer.

Note: steel window supports below windows are still not covered with thermal insulation and therefore they appear as thermal bridge.

The building is still under construction and due to the weather conditions the drying process of the building is slowed down and materials (concrete etc) still contain moisture. Heating system and Ventilation with heat recuperation was set up only about 1.5 months ago.
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01-04-2014, 01:53 PM (This post was last modified: 01-04-2014 02:39 PM by David Marek.)
Post: #9
Building facade temperature appears cooler then the atmospheric temperature
       
.pdf  04.pdf (Size: 1.04 MB / Downloads: 8) JPG+PROTOCOL LIST+IR image 04

Conditions:

Morning before the sunrise
Air temp: 2.2°C
Refl. temp: -5°C (the image was shooted inside partly covered entrance as shown on JPG)
Emissivity set up for SP1, SP2: 0.95 ( facade mineral insulation covered with plaster base+ plaster / final facade finish not done yet: emissivity 0.88)
No wind, snow,rain etc.
Interior of the building was heated up to 20°C about 20 hours before the IR scanning

TARGET:

Vertical walls and ceiling of the semi opened entrance are covered with thermal insulation+plaster. The exterior floor is concrete. Sp1,Sp2 indicates heat coming from the interior (+20°C). This may be due to the disconnected iron mesh of the reinforced concrete floor that goes from the interior to the exterior and thus creates thermal bridge.Underneath the vertical wall there is a foam glass insulation as to thermally disconnect the wall from the floor....

The building is still under construction and due to the weather conditions the drying process of the building is slowed down and materials (concrete etc) still contain moisture. Heating system and Ventilation with heat recuperation was set up only about 1.5 months ago.

       
.pdf  05.pdf (Size: 878.88 KB / Downloads: 7) JPG+PROTOCOL LIST+IR image 05

Conditions:

Morning before the sunrise
Air temp: 3.4°C
Refl. temp: -10°C (the image was shooted inside partly covered entrance as shown on JPG)
Emissivity set up for various measured points on facade: 0.88 ( facade mineral insulation covered with plaster base+ plaster / final facade finish not done yet )
No wind, snow,rain etc.
Interior of the building was heated up to 20°C about 20 hours before the IR scanning

TARGET:

To reveal if the mineral insulation was layered properly without any gaps or other procedure failures like injecting glue in insulation seams etc. Thermal insulation+plaster base+plaster is on the building already for some time (rain, wind etc) and the IR scanning was taken before the facade is covered with final finish to avoid cracks etc. on the final finish facade layer.

The ceiling covered with plaster base+plaster indicates slightly higher temp. This may be due to the fact that the vertical walls are from the exterior covered with soil and the ceiling divides exterior temp. from the interior temp. (+20°C) ass seen on JPG.

The building is still under construction and due to the weather conditions the drying process of the building is slowed down and materials (concrete etc) still contain moisture. Heating system and Ventilation with heat recuperation was set up only about 1.5 months ago

       
.pdf  06.pdf (Size: 1.3 MB / Downloads: 14) JPG+PROTOCOL LIST+IR image 06

Conditions:

Morning before the sunrise
Air temp: 1.4°C
Refl. temp: -35°C (the camera was not directed upwards to the sky but still reflects semi opened surrounding conditions with houses, trees etc. but from a distance)
Emissivity set up for various measured points on facade: 0.88 ( facade mineral insulation covered with plaster base+ plaster / final facade finish not done yet )
No wind, snow,rain etc.
Interior of the building was heated up to 20°C about 20 hours before the IR scanning

TARGET:

To reveal if the mineral insulation was layered properly without any gaps or other procedure failures like injecting glue in insulation seams etc. Thermal insulation+plaster base+plaster is on the building already for some time (rain, wind etc) and the IR scanning was taken before the facade is covered with final finish to avoid cracks etc. on the final finish facade layer.


The building is still under construction and due to the weather conditions the drying process of the building is slowed down and materials (concrete etc) still contain moisture. Heating system and Ventilation with heat recuperation was set up only about 1.5 months ago

       
.pdf  07.pdf (Size: 445.86 KB / Downloads: 11) JPG+PROTOCOL LIST+IR image 07

Conditions:

Morning before the sunrise
Air temp: 1.5°C
Refl. temp: -50°C (although the camera was not directed upwards to the sky)
Emissivity set up for various measured points on facade: 0.88 ( facade mineral insulation covered with plaster base+ plaster / final facade finish not done yet )
No wind, snow,rain etc.
Interior of the building was heated up to 20°C about 20 hours before the IR scanning

TARGET:

To reveal if the mineral insulation was layered properly without any gaps or other procedure failures like injecting glue in insulation seams etc. Thermal insulation+plaster base+plaster is on the building already for some time (rain, wind etc) and the IR scanning was taken before the facade is covered with final finish to avoid cracks etc. on the final finish facade layer.


The building is still under construction and due to the weather conditions the drying process of the building is slowed down and materials (concrete etc) still contain moisture. Heating system and Ventilation with heat recuperation was set up only about 1.5 months ago

       
.pdf  08.pdf (Size: 467.8 KB / Downloads: 11) JPG+PROTOCOL LIST+IR image 08

Conditions:

Morning before the sunrise
Air temp: 1.1°C
Refl. temp: -15°C (the camera was not directed upwards to the sky but towards the ground)
Emissivity set up for various measured points on facade: 0.88 ( facade mineral insulation covered with plaster base+ plaster / final facade finish not done yet )
No wind, snow,rain etc.
Interior of the building was heated up to 20°C about 20 hours before the IR scanning

TARGET:

To reveal if the mineral insulation was layered properly without any gaps or other procedure failures like injecting glue in insulation seams etc. Thermal insulation+plaster base+plaster is on the building already for some time (rain, wind etc) and the IR scanning was taken before the facade is covered with final finish to avoid cracks etc. on the final finish facade layer.


The building is still under construction and due to the weather conditions the drying process of the building is slowed down and materials (concrete etc) still contain moisture. Heating system and Ventilation with heat recuperation was set up only about 1.5 months ago

       
.pdf  09.pdf (Size: 450.54 KB / Downloads: 10) JPG+PROTOCOL LIST+IR image 09

Conditions:

Morning before the sunrise
Air temp: 1.7°C
Refl. temp: -50°C
Emissivity set up for various measured points on facade: 0.90 ( facade above windows covered only with extruded polystyren thermal insulation )
No wind, snow,rain etc.
Interior of the building was heated up to 20°C about 20 hours before the IR scanning

TARGET:

To reveal if the mineral insulation was layered properly without any gaps or other procedure failures like injecting glue in insulation seams etc. Thermal insulation+plaster base+plaster is on the building already for some time (rain, wind etc) and the IR scanning was taken before the facade is covered with final finish to avoid cracks etc. on the final finish facade layer.

Note: steel window supports below windows are still not covered with thermal insulation and therefore they appear as thermal bridge.

The building is still under construction and due to the weather conditions the drying process of the building is slowed down and materials (concrete etc) still contain moisture. Heating system and Ventilation with heat recuperation was set up only about 1.5 months ago

       
.pdf  10.pdf (Size: 428.32 KB / Downloads: 7) JPG+PROTOCOL LIST+IR image 10

Conditions:

Morning before the sunrise
Air temp: 0.2°C
Refl. temp: -60°C
Emissivity set up for various measured points on facade: 0.90 ( facade above windows covered only with extruded polystyren thermal insulation )
No wind, snow,rain etc.
Interior of the building was heated up to 20°C about 20 hours before the IR scanning

TARGET:

To reveal if the mineral insulation was layered properly without any gaps or other procedure failures like injecting glue in insulation seams etc. Thermal insulation+plaster base+plaster is on the building already for some time (rain, wind etc) and the IR scanning was taken before the facade is covered with final finish to avoid cracks etc. on the final finish facade layer.

The building is still under construction and due to the weather conditions the drying process of the building is slowed down and materials (concrete etc) still contain moisture. Heating system and Ventilation with heat recuperation was set up only about 1.5 months ago

       
.pdf  11.pdf (Size: 486.17 KB / Downloads: 9) JPG+PROTOCOL LIST+IR image 11

Conditions:

Morning before the sunrise
Air temp: 1°C
Refl. temp: -5°C (camera is not directed at the sky)
Emissivity set up for various measured points on facade: 0.88 (facade mineral insulation covered with plaster base+ plaster / final facade finish not done yet )
No wind, snow,rain etc.
Interior of the building was heated up to 20°C about 20 hours before the IR scanning

TARGET:

To reveal if the mineral insulation was layered properly without any gaps or other procedure failures like injecting glue in insulation seams etc. Thermal insulation+plaster base+plaster is on the building already for some time (rain, wind etc) and the IR scanning was taken before the facade is covered with final finish to avoid cracks etc. on the final finish facade layer.

The building is still under construction and due to the weather conditions the drying process of the building is slowed down and materials (concrete etc) still contain moisture. Heating system and Ventilation with heat recuperation was set up only about 1.5 months ago

JPG+PROTOCOL LIST+IR image 12

Conditions:

Morning before the sunrise
Air temp: 2.6°C
Refl. temp: -60°C (camera directed at the sky)
Emissivity set up for various measured points on facade: 0.88 (facade mineral insulation covered with plaster base+ plaster / final facade finish not done yet )
No wind, snow,rain etc.
Interior of the building was heated up to 20°C about 20 hours before the IR scanning

TARGET:

To reveal if the mineral insulation was layered properly without any gaps or other procedure failures like injecting glue in insulation seams etc. Thermal insulation+plaster base+plaster is on the building already for some time (rain, wind etc) and the IR scanning was taken before the facade is covered with final finish to avoid cracks etc. on the final finish facade layer.

The building is still under construction and due to the weather conditions the drying process of the building is slowed down and materials (concrete etc) still contain moisture. Heating system and Ventilation with heat recuperation was set up only about 1.5 months ago


Attached File(s) Thumbnail(s)
       

.pdf  12.pdf (Size: 473.35 KB / Downloads: 10)
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01-09-2014, 06:00 AM
Post: #10
RE: Building facade temperature appears cooler then the atmospheric temperatuWHY?
Hi,
I meant cooling by dew/water evaporation.. On pictures taken 16.Dec. - was there any dew or white frost on soil that morning ? It should be, as there was relatively warm previous day (+7C) and very cold, clear sky in the night, air temp good below 0'C probably... During your inspection air temperature rised quickly, and came up north wind to 5m/s - good time to evaporate dew settled on low thermal capacity places, like ETICS thin film plaster.
Despite of question why wall seems to be colder then air, all details and patterns of isolation faults are clearly visible, then your report - as for me - is fine ..

Best wishes from Poland.
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