JPH0777460A - Detecting method for outer wall peel section with thermal image - Google Patents

Abstract

PURPOSE:To detect a peel section having a large temperature difference with high reliability by obtaining the temperature difference twice or above at a high temperature and at a low temperature on a thermal image of the outer wall. CONSTITUTION:A thermal image is obtained on portions of the outer wall including a peel portion at least twice at a high temperature with a large sunshine quantity and at a low temperature after sunshine with an infrared camera. This thermal image is processed by an image processor, and individual points of the thermal image displayed on a CRT or the like are displayed in the density or color tone corresponding to the measured temperature. The temperature differences between the high temperature and the low temperature is obtained at individual points on a screen for the whole measurement range of the outer wall, and individual points are displayed based on the temperature difference. The temperature difference is larger at the peel portion than at an adhesive portion, and the peel portion is clearly displayed on the thermal image, with the adhesive portion serving as a background.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for detecting a peeled portion of an outer wall, which can determine the peeled portion of an outer wall easily and reliably. On the outer wall of the building, exterior materials such as mortar and tiles are provided on the surface of the structural material.The exterior materials are exposed to wind and rain and sunlight, and are partially distorted due to direct changes in temperature and climate. There is a case where it occurs, peels off, and falls off for a while. The exfoliation of the exterior material not only impairs the durability of the building but also causes a fall accident, so early detection is required. The present invention provides a method for detecting an exfoliated portion of an outer wall, which is simpler and more reliable than conventional methods, by using a thermal image of the outer wall.

[0002]

2. Description of the Related Art A hitting method has heretofore been generally used as a method for determining a separated portion of an outer wall, but the work efficiency is low, and it is necessary to temporarily install a scaffold for work over the entire measurement range. In recent years, a method of diagnosing a thermal image using an infrared camera has been devised and is being used. Conventionally,
The thermal image determination method used is that the peeled part of the outer wall has a higher heat transfer resistance than the close contact part (healthy part) due to the presence of an air layer inside, and therefore the temperature is different from the temperature of the close contact part. The thermal image of the outer wall is taken by the infrared camera during the time when the amount of sunlight is almost maximum, and the part of the temperature change appearing on the thermal image is empirically diagnosed to determine the peeling point. .

However, the actual thermal image of the outer wall shows, in addition to the temperature difference caused by the peeling, the temperature difference between the rooms due to the heating inside the building, and the cooling of the building structure such as the joint between the outer wall and the slab and the partition wall. Temperature difference due to bridge, dirt on wall surface,
There are many factors that cause noise in peeling judgment such as radiation of neighboring buildings, and judgment is made empirically by distinguishing them, so skill is required for judgment, and personal judgment error is large and reliability is low. There's a problem. Further, since the conventional method is a so-called primary image judgment method in which the thermal image of the outer wall is perceptually judged as it is, the sunshine duration is long so that the temperature difference between the contact portion and the peeled portion is clear, and the sun is still used. The thermal image of the time zone when the amount of sunshine in the inside is almost maximum is used.
For this reason, there was a problem that it was not possible to determine the extremely short sunshine hours and the north side where the sun did not shine. Especially in cold regions, there are major problems such as the heat insulation structure of buildings and the influence of heating heat on thermal images, and the detection capability at low temperatures.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a peeling detection method which solves the above problems of the conventional method using a thermal image. Whereas the conventional determination method is a method of directly comparing the peeled portion and the close contact portion by directly using the primary thermal image of the outer wall, the present invention directly determines the primary thermal image of the outer wall. Instead, the thermal image of the outer wall including the peeled part and the adhered part is taken at high temperature during the day and at least 2 times after the sunshine, or at high temperature during the day and at least 2 times during the low temperature in the evening or night. This is a method of detecting the temperature difference by measuring with this, and detecting the peeled portion by the secondary thermal image that has been subjected to the difference processing for this temperature. By this difference processing, a reliable peeled portion detection method that solved the conventional problem was achieved. It was done.

[0005]

According to the present invention, the following method for detecting a peeled portion of the outer wall is provided. (1) In a method of determining a peeling portion based on a temperature difference between a close contact portion and a peeling portion of the outer wall shown in a thermal image of the outer wall, a temperature difference between at least two times of high temperature and low temperature of the outer wall is obtained from the thermal image, A method for detecting an outer wall peeling portion by a thermal image, wherein a peeling portion where the temperature difference is large is detected with respect to the close contact portion where the temperature difference is small, by the temperature difference. (2) Regarding the outer wall, the temperature at least two times at a high temperature during the daytime and a low temperature after the daylight with a large amount of sunlight is obtained, and the peeling portion is detected by the temperature difference based on the difference in the amount of sunlight.
Method (1). (3) Obtain the temperature of the outer wall at least two times during the daytime when the outside air temperature is high and at the time when the outside temperature is low in the evening or at night, and detect the peeling part by the temperature difference based on the temperature difference during the day. The method of (1) above.

Since an air layer exists between the exterior and the building wall surface in the separated portion of the outer wall, this serves as a heat insulating layer, and the heat transfer resistance becomes larger than that of the surrounding close contact portion (healthy portion). Therefore, the amount of heat transferred to the building wall surface at the peeling portion is smaller than that in the surroundings during sunshine or when the outside air temperature is in the process of rising, and the surface temperature of the peeling portion becomes higher than that in the surrounding closely contacting portion. On the other hand, after sunlight or when the outside air temperature is in the process of falling, the surface temperature of the peeled portion becomes lower than that of the surroundings because the heat supply from the wall surface is small. The present invention pays attention to such a difference in the amount of sunlight and a difference in temperature change between the peeling portion and the contact portion due to the change in the outside air temperature, and at least 2 when the outer wall has a high sunlight amount and a low temperature after the sunlight. The temperature difference of time or the temperature difference of at least two times between the time zone where the outside air temperature is high during the day and the time zone where the outside air temperature is low during the evening to the night is obtained by a thermal image, and the temperature difference is small for the contact portion. The peeled portion where the temperature difference largely appears is detected by the temperature difference. In the present invention,
The high temperature during the day means a time period when the wall temperature of the building is high during the day, and means several hours including a time period when the temperature of the building is highest due to the sunshine. As shown in the examples,
On the east side of the building, the temperature difference between the exfoliated part and the sound part becomes maximum about 2 hours after the peak of sunshine, and on the south side and the west side, the temperature difference becomes maximum at the peak of insolation. It can be said that this time zone is the optimum measurement time zone for measurement. Further, in the present invention, the low temperature refers to a time zone in which the wall surface temperature of the building is sufficiently lower than the temperature at the high temperature, and includes a time zone from the end of solar radiation to the evening and night.

Specifically, as an example, for each part of the outer wall including the peeled part, an infrared camera is used, and when the amount of sunlight is high (temperature T1) and after the sunshine is low (temperature T2).
Of the at least two time points, or at least two time points of the daytime outside temperature range (temperature T1) and the evening to nighttime outside temperature time period (temperature T2). A thermal image taken by an infrared camera is processed by an image processing device, and a thermal image displayed on a CRT or the like has each point on the screen displayed with a density or color tone corresponding to the measured temperature. Here, for the entire measurement range of the outer wall including the peeled portion, a temperature difference (ΔT =) obtained by subtracting the temperature T2 at low temperature from the temperature T1 at high temperature at each point on the screen.
T1 -T2) is obtained and each point is represented by this temperature difference ΔT. This temperature difference ΔT has a larger temperature difference in the peeling portion than in the contacting portion. Therefore, in the secondary thermal image represented by this temperature difference ΔT, the contacting portion (healthy portion) having a small temperature difference is used as the background. The peeled portion with a large temperature difference is clearly displayed. In addition, various noises included in the primary thermal image are deleted from the secondary thermal image obtained by performing the differential processing on the primary thermal image at least at two times in this way.
For example, the temperature difference between the rooms due to heating inside the building, the temperature difference due to the structural material of the building such as the joint between the outer wall and the slab, the partition wall, etc. Even if it is displayed as a large temperature difference in the thermal image,
In the next thermal image, the area has a small temperature difference, and the influence is removed. Therefore, the peeled portion can be clearly and accurately grasped.

In the method of the present invention, the temperature of the outer wall at high temperature and at low temperature at least two times may be measured and the temperature difference may be obtained. Therefore, it is possible to measure the temperature at least two times at high temperature in the daytime with high sunshine and at low temperature after sunshine, and obtain the temperature difference based on this difference in the sunshine amount. For the back side part or the part where the sun does not illuminate such as the north side, find the temperature at least two times during the daytime when the outside air temperature is high and during the evening or nighttime when the outside temperature is low. The temperature difference may be calculated based on the difference. According to the experiment, when the temperature difference based on the difference in the amount of sunlight is used, highly reliable determination is possible if the temperature difference between the contact portion and the peeling portion is about 1 ° C to 0.5 ° C. Further, when using the temperature difference of one day, the temperature difference may be about 10 ° C. or more.

[0009]

The method of the present invention using the secondary thermal image displayed by the temperature difference has the following effects. (1) Compared with the conventional method, various error factors that are difficult to distinguish with the conventional determination method, such as the effect of heating inside the building, the effect of the building structure such as a cold bridge, and the effect of dirt on the wall surface are eliminated. As a result, the detection accuracy of the peeled portion is remarkably excellent, the determination work does not require skill, and personal error does not occur, so that highly reliable diagnosis can be performed. (2) Since it is possible to eliminate the influence of heating heat inside the building even in cold regions, it is possible to make a highly reliable determination of the peeled portion throughout the year. (3) Even if the peeling thickness is small, the exterior material is too thick, the amount of sunlight is small, etc., the temperature difference between the adhered portion and the peeled portion is small, and the peeled portion can be accurately detected even when the conventional method cannot determine. Can be determined.

[0010]

EXAMPLES Examples of the present invention will be shown below. The following examples are illustrative of the present invention and do not limit the present invention.

Example 1 (Sample Test) (A) Specification of Test Wall As a test wall, a P having a width of 900 mm × height of 1700 mm × thickness of 150 mm was used.
50mm square, 100mm square, 200mm square, 300mm
0.1mm thick poly film or thickness 1,2,
After attaching 3mm styrene paper, thickness 20mm, 30
The one coated with mm mortar was used. (B) Test condition The test wall was exposed to the sun from sunrise to 2-3 hours after sunset, and a thermal image was recorded every 30 minutes. At the same time, the surface temperature of the peeled portion, the outside air temperature, the amount of sunlight, and the wind speed were measured. The test was performed several times by changing the direction of the test wall. Table 1 shows the orientation of the test wall and the weather conditions on the test day. All tests were conducted in the same place. For thermal image capturing, two types were used in combination, a model mainly detecting a wavelength range of 3 to 5 μm (SW machine) and a model mainly detecting 8 to 13 μm (LW machine). Further, in order to confirm the effect of the present invention, a thermocouple was attached to each sample, the surface temperature was measured, and determination by the tapping method was also performed.

(D) Test Results The above test results are shown in Table 2. The results obtained by the tapping method are shown in Table 3. The above tests confirmed the following. (1) Appearance of peeling portion and time zone The time zone when the high temperature region of the peeling portion appears on the thermal image is the longest portion on each of the southeast, southwest, and south planes, and it is about 5 times across the peak of solar radiation. It is about 6 hours, and it is about 6 hours on the north side in fine weather, with the outside air temperature being at the peak, and the peeling part is most clear at the peak of the amount of solar radiation (at the outside temperature on the north side). A difference was recognized depending on the peeling state and the wavelength band detected by the infrared camera. In some samples, the peeled portion appeared at a low temperature immediately after the direct solar radiation disappeared, and became clear after a further 1 to 2 hours. Even if there is no insolation on the north side, there will be a temperature difference if there is a sufficient amount of fluctuation in the outside air temperature. (2) Difference due to peeling thickness The larger the peeling thickness, the larger the temperature difference between the peeled part and the sound part,
The contours also appear clearly, and the time period for distinguishing the peeled part is long. (3) Difference due to peeled area The larger the peeled area, the clearer the contour of the peeled portion. 50 mm
Regarding the corner, there is almost no temperature difference even when actually measured, and it cannot be detected. Even for 100 mm square, there is rarely a temperature difference and the contour cannot be determined. For 200 mm square or more, the contour can be determined. (4) Difference in mortar thickness A thinner mortar reacts more sensitively to changes in solar radiation and outside air temperature. That is, the thinner the mortar is, the faster the daytime high temperature area and the evening low temperature area appear at the exfoliation part, and the faster they disappear. In addition, the thinner the mortar, the sharper the contour of the peeled portion, and the thinner the mortar, the thinner the mortar can be discriminated. (5) Difference by infrared camera About LW machine (long wavelength machine) and SW machine (short wavelength machine)
The image of the W machine (long wavelength machine) is clearer, the discrimination accuracy of the peeled portion is higher, and the discriminable time period is longer. The biggest cause of the SW machine is that reflected light from the wall surface is easily reflected when it is exposed to direct sunlight. Further, when the wall surface temperature is low, the image is unclear on the SW machine, which is disadvantageous for diagnosis in the cold season.
The SW machine is more likely to be affected even when artificially disturbed by a lamp or the like. On the other hand, as shown in FIG. 1, when the display temperature on the thermal image is compared with the actually measured temperature, the LW machine as a whole is displayed slightly higher than the actually measured temperature. In the SW machine, it is slightly low when the solar radiation is not hit, but it is displayed higher when the solar radiation is hit, and the larger the reflectance is, the larger the difference from the measured temperature is. (6) Comparison with tapping method Compared with the detection result of the tapping method of the peeled part, the one with a small peeling area cannot be detected by the tapping method, but a peeling thickness of 0 mm can be detected if the peeling area is large. .. When the peeling thickness is 1 mm or more, there is no great difference between the thermal image by the LW machine and the discrimination result by the tapping method.

Example 2 (Building test) (A) Test building Four-story wall-type reinforced concrete structure elongated in the east and west directions, exterior mortar 20 to 30 mm finished by spraying with rinsing, building age 3
No large-scale collection of outer walls for 0 years. There are no standing trees around the building and there are no nearby buildings that block sunlight. (B) Test conditions Thermal images of the outer wall are measured every 30 minutes from sunrise to about 3 hours after sunset. Infrared camera (SW) on each side of the building
Machine, LW machine). Table 1 shows the outside temperature, climate, sunshine on each side of the building, and wind speed. The measurement period is twice in spring and summer. A thermocouple was attached to the measurement point of the building to measure the surface temperature. The test results are shown in FIGS. 2 (A) (B) (C) and FIGS. 3 (A) (B) (C).

(C) Test results (1) Spring test Since the spring test is during the heating period, heat leakage from the cold bridge such as the floor slab and the joint between the partition wall and the outer wall is observed in the thermal image before solar radiation. Is visible [Fig. 2 (A)], and after insolation, the high temperature region of the peeling part and the high temperature region due to the cold bridge are mixed.
[FIG. 2 (B)] In both cases, the peeled portion cannot be identified from the thermal image at 1 hour. A secondary thermal image in which these measurement results are subjected to difference processing according to the present invention and expressed by a temperature difference at two times
In [Fig. 2 (C)], the heat leakage from the cold bridge is eliminated, and the peeled portion is clearly shown in comparison with the surrounding sound part. Further, by displaying the temperature difference, noise such as stains on the wall surface, which does not fluctuate with time, is eliminated, and the peeled area buried in the noise appears clearly in the secondary thermal image in the primary thermal image. (2) Summer test In the summer test on the north side of the building, due to lack of insolation and uneven insolation, the outside temperature does not depend on
Temperature difference between two times [Fig. 3 (A)] and night [Fig. 3 (B)]
By using (C)], the peeled area can be accurately determined. (3) Comparison with measured temperature If there is no influence of the cold bridge, when the temperature difference between the sound part and the peeling part is approximately 1 ° C or less, specify the peeling part in the primary thermal image displayed at the temperature at one time. However, according to the secondary thermal image due to the temperature difference of the present invention, the peeled portion can be specified even if the temperature difference between the sound portion and the peeled portion is about 0.5 ° C.

[Brief description of drawings]

FIG. 1 is a graph showing an actually measured temperature and a thermal image display temperature in Example 1.

FIG. 2 is a schematic diagram of thermal images showing the results of the spring test of Example 2, (A) and (B) being primary thermal images before and after solar irradiation,
(C) is the secondary thermal image due to these temperature differences, and the dark part in the figure is the high temperature region.

FIG. 3 is a schematic diagram of thermal images showing the results of the summer test of Example 2, (A) and (B) being primary thermal images before and after solar irradiation,
(C) is the secondary thermal image due to these temperature differences, and the dark part in the figure is the high temperature region.

[Table 1]

[Table 3]

[Table 2]

Front Page Continuation (72) Inventor Noriaki Seo 19-16 Kita 16 Higashi, Higashi-ku, Sapporo, Hokkaido Japan Data Service Co., Ltd. In the Toa Solo Reform (72) Inventor Osamu Tobishima 6-3-25 Kikusui, Shiroishi-ku, Sapporo, Hokkaido Inside Sapporo Parkerizing Co., Ltd. No. 10 Chemical Co., Ltd. (72) Inventor Atsushi Himi 2-1-1, Kita 1-jo Nishi, Chuo-ku, Sapporo-shi, Hokkaido Udit Co., Ltd.

Claims (3)

[Claims] 1. A method for determining a peeling portion based on a temperature difference between a close contact portion and a peeling portion of the outer wall shown in a thermal image of the outer wall, wherein the temperature difference between the high temperature and the low temperature of the outer wall is at least two times. A method of detecting an outer wall peeling portion by a thermal image, wherein the peeling portion where the temperature difference is large is detected with respect to the close contact portion where the temperature difference is small, by the temperature difference. 2. The temperature of the outer wall at least at two times when the temperature is high during the day when the amount of sunlight is large and when the temperature is low after the sunshine,
The method according to claim 1, wherein the peeling portion is detected by a temperature difference based on the difference in the amount of sunlight. 3. The temperature of the outer wall at least two times during the daytime when the outside air temperature is high and in the evening or at night when the outside air temperature is low, and the peeling portion is obtained by the temperature difference based on the temperature difference during the day. The method of claim 1, wherein