JP6874414B2 - Dismantling method - Google Patents

Description

The present invention relates to a demolition method for demolition of at least a part of a building including a ceiling.

Conventionally, a large amount of dust is usually generated in the demolition or renovation work of a building. In particular, since a large amount of Aspergillus spores are contained in the dust generated by renovation and repair work in the hospital, mold spores are sucked in hospitals and elderly facilities where patients with weakened immunity and the elderly are present. Increases the risk of Aspergillus infection. Therefore, measures against aspergillosis in construction have been attracting attention (see, for example, Non-Patent Document 1).

Non-Patent Document 1 describes that, regarding Aspergillus dispersal during construction, a countermeasure class is specified according to the scale and risk, and specific infection preventive measures are taken for each class. For example, as a countermeasure method, a unit having a HEPA filter (High Efficiency Particulate Air Filter) is used to keep the work site in a negative pressure state.

On the other hand, molds of the genus Aspergillus are derived from soil and enter the building through air from the soil. Furthermore, this mold is more resistant to drying than other molds and can grow even at temperatures above 30 ° C. Therefore, it is presumed that many Aspergillus molds are present in places where dust is accumulated, such as in the ceiling.

Therefore, we actually investigated the number of molds adhering to the ceiling and the interior walls and floors.
FIG. 12 shows the results of investigation (number of adhered molds) in a predetermined building. It was below the measurement limit on the indoor wall surface, and extremely small on the floor surface. On the other hand, in the attic, mold was found several to ten times more than the floor. In addition, when we investigated the types of molds present in the attic, the proportion of molds of the genus Aspergillus was high.

FIG. 13 shows the ratio of mold existing on the indoor floor surface by type before and after dismantling. On the indoor floor surface before dismantling, hygroscopic Fusarium and Aureobasidium molds were confirmed, but Aspergillus molds were not confirmed. On the other hand, on the floor surface after dismantling, molds of the genus Aspergillus accounted for a large proportion.

Edited by National University Hospital Infection Control Council, "Hospital Infection Control Guidelines Revised 2nd Edition", Jiho Co., Ltd., January 2015, p173-175

During the demolition work, workers come and go and demolition objects are carried in and out. Therefore, as mentioned in the non-patent literature, it is difficult to maintain a strict negative pressure. Further, since the HEPA filter has a fine mesh, it is easily clogged, the frequency of replacement is high, and the work efficiency is poor. Furthermore, it is necessary to suppress the onset of Aspergillus infection among workers in the construction site under negative pressure.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a dismantling method for suppressing the scattering of Aspergillus bacteria and suppressing the onset of Aspergillus infection.

-The dismantling method for solving the above problem is a dismantling method for dismantling at least a part of a building, in which the ceiling is constructed after performing a mold removal treatment for sterilizing the mold in the ceiling of the target area of the dismantling. Dismantle the ceiling member. As a result, the mold of the genus Aspergillus is reduced in the attic where many molds of the genus Aspergillus are present, and then the mold is dismantled, so that the mold of the genus Aspergillus can be avoided from scattering. Therefore, it is possible to suppress the scattering of Aspergillus mold and reduce the risk of Aspergillus infection.

-In the above dismantling method, it is preferable to perform the mold removal treatment by spraying the mold removal liquid on the ceiling. As a result, the attic can be efficiently removed from mold.

-In the above dismantling method, it is preferable to dismantle the ceiling member after spraying the mold removing liquid and leaving it for a predetermined time or longer. As a result, it is possible to reduce the mold of the genus Aspergillus in the ceiling and reduce the influence of the mold remover on the human body.

-In the above dismantling method, it is preferable to measure the humidity behind the ceiling and specify the amount of the mold removing liquid to be sprayed according to the measured humidity. As a result, the amount of the mold remover can be appropriately controlled to reduce the mold of the genus Aspergillus.

-In the above-mentioned dismantling method, it is preferable to spray the mold-removing liquid for each compartment after dividing into compartments for spraying the mold-removing liquid according to the area and wall arrangement of the target area for dismantling. .. As a result, the chemical solution can be efficiently distributed behind the ceiling to be dismantled to remove mold.

-In the above dismantling method, an opening is formed in the ceiling of the target area for dismantling, and a sprayer for spraying the mold removing liquid is placed behind the ceiling through the opening to close the opening, and then the opening is closed. It is preferable to spray the mold removing liquid from the sprayer onto the ceiling. As a result, it is possible to suppress the leakage of the spray from the opening.
-In the above dismantling method, it is preferable to spray the mold removing liquid using a two-fluid nozzle. As a result, the fungicide-removing liquid is sprayed with a mist of fine particles, so that the fungicide-removing liquid can be evenly distributed over a wide range.

According to the present invention, it is possible to suppress the scattering of Aspergillus bacteria and suppress the onset of Aspergillus infection.

The flow chart explaining the processing procedure of the dismantling method in an embodiment. The schematic block diagram explaining the structure of the mist sterilization apparatus in embodiment. The plan view of the building explaining the partitioning process of the attic in the embodiment. A table illustrating the amount of chemical to be sprayed in the embodiment. The explanatory view explaining the arrangement of the mist sterilization apparatus in an embodiment. A table illustrating the antifungal effect in the embodiment. It is explanatory drawing for demonstrating the attic used in the experiment for determining the amount of chemicals in an embodiment, (a) is a small attic, (b) is a large attic. A table explaining the antifungal effect of the chemical solution used in the experiment. A table explaining the antifungal effect in the experiment. Explanatory drawing explaining the relationship between the relative humidity rise amount calculated from an experiment and the amount of a spray liquid. Explanatory drawing explaining the temporal change of chlorine gas of the chemical solution obtained from an experiment. A graph showing the number of molds adhering to each location in the prior art. A graph showing the types of mold existing on the floor before and after dismantling in the prior art.

Hereinafter, an embodiment embodying the present invention will be described with reference to FIGS. 1 to 11.
FIG. 1 shows a processing procedure of the disassembling method in the present embodiment. In this embodiment, it is assumed that a section of a building including a ceiling is dismantled in order to repair a part of a building such as a hospital. In the present embodiment, the ceiling is dismantled after removing mold from the ceiling by spraying a chemical solution with mist spray.

(Configuration of mist sterilizer)
The configuration of the mist sterilizing device 20 used for removing mold from the ceiling will be described with reference to FIG.

The mist sterilizer 20 of the present embodiment includes a portable atomizer 21, a chemical solution tank 26, an air tank 27, and a compressor 28. The atomizer 21 is attached to the support portion 30 and is supported by the support portion 30. The atomizer 21 is provided with a plurality of two-fluid nozzles 22. Each of the two fluid nozzles 22 is provided with a spray port so that the chemical solution can be sprayed in the opposite direction. The sprayer 21 has an air intake portion and a liquid intake portion, mixes the air and the liquid, and sprays the mist-like liquid from the spray port of the two-fluid nozzle 22. In the present embodiment, as the sprayer 21, spraying provided with a two-fluid siphon type spray nozzle is used. Specifically, the trade name Mini Fogger III manufactured by Spraying Systems Japan Co., Ltd. is used. The chemical solution (mold remover) from the chemical solution tank 26 is supplied to the liquid intake portion of the sprayer 21. Compressed air is supplied from the air tank 27 to the air intake portion of the atomizer 21. A compressor 28 is connected to the air tank 27, and compressed air is supplied. The mist sterilizer 20 can control the amount of spray liquid per hour of the mist sterilizer 20 by the air pressure of the compressed air from the air tank 27. In this embodiment, a 100 V compressor 28 can simultaneously spray from two two-fluid nozzles 22.

(Building demolition procedure)
Next, the procedure for dismantling the building will be described with reference to FIG.
In the present embodiment, first, the attic is divided (step S1). In this process, the attic is divided into rectangular areas (sections) of a predetermined area or less that can be removed by the mist spray used, using the plan view of the area to be demolished (the area to be demolished) of the building. In the present embodiment, the area where mold can be removed by the mist sterilizer 20 is 40 m ² . Therefore, the area of one section shall be 40 m ² or less, and it shall be divided into areas along the wall layout of the building. The area where mold can be removed was calculated by an experiment described later.

For example, as shown in FIG. 3, in a ^{room R1 having an area of 40 m 2} or less, the attic of the room is divided into one area A11. Further, in the large room R2, the area is divided into three areas A21, A22, and A23 so that the ^{area is 40 m 2 or less.} Further, the attic of the corridor C1 is divided into areas A31, A32, etc. so ^{that the area is 40 m 2 or less.}

Next, an opening is formed in the ceiling (step S2). Specifically, a hole is made in the ceiling (ceiling plate) at the center position of each section divided in step S1 to form an opening. In this case, the opening is large enough to allow the atomizer 21 to pass through.

Then, the temperature and humidity behind the ceiling are measured (step S3). Specifically, the humidity sensor is inserted into the ceiling through the opening formed in step S2, and the humidity sensor is installed in the ceiling. Then, by installing this humidity sensor in the ceiling for a predetermined period (for example, 3 to 5 minutes), the temperature and humidity in the ceiling are measured.

Next, the amount of the chemical spray is determined according to the temperature and humidity (step S4). Specifically, the amount of spray liquid is specified according to the measured humidity (initial relative humidity).
Here, using the chemical amount specification table shown in FIG. 4, the chemical amount is specified according to the initial relative humidity so that the target relative humidity is 85%. Chemical amount specified in this chemical solution amount determination table, the spraying liquid volume of 1 m ³ per calculated from the approximate expression of the spray liquid amount and the relative humidity increased amount of experimental results described later, the safety factor (here, "1. Use the amount multiplied by 5 ”). Incidentally, in FIG. 4, and the spray liquid amount per unit area, and the spray liquid amount of actual use in the ceiling of the size of the volume of 11m ^{3, 16m} 3, 22m 3 for reference, the spray liquid quantity The spraying time converted to time is shown. When the initial relative humidity is lower than 40% RH, the relative humidity is set to 40% RH or more by humidification, and the initial relative humidity is set to 40% RH, and the chemical solution is sprayed.

Next, a mist sterilizer is installed (step S5). Specifically, as shown in FIG. 5, the chemical solution tank 26, the air tank 27, and the compressor 28 are installed in the room of the target area for dismantling, and the atomizer 21 is inserted through the opening and installed behind the ceiling. In this case, the sprayer 21 is installed so that the spray port of the two-fluid nozzle 22 has a height of 30 cm to 40 cm from the ceiling surface. Further, the spray port of the bifluid nozzle 22 is installed so as to be located on the diagonal line of the section to be removed from mold.

In this case, the atomizer 21 installed behind the ceiling is supported by the support member 31 arranged in the room via the support portion 30. Then, the opening h1 is covered with the covering member 35 so that the spray does not leak from the opening h1. As the covering member 35, a sheet made of synthetic resin such as a vinyl sheet or a blue sheet is used.

In this state, mist spraying is performed (step S6). Specifically, the two-fluid nozzle 22 of the installed atomizer 21 continues to spray the chemical solution for the spraying time corresponding to the amount of the chemical solution sprayed determined in step S4.

In the present embodiment, the chemical solution to be sprayed is an aqueous hypochlorous acid solution that is chlorine-based and has a disinfecting effect to sterilize mold. Specifically, a 6% sodium hypochlorite solution (trade name: Purax (registered trademark), manufactured by Oyalux Co., Ltd.) is diluted with tap water to 0.3% (3000 mg / L), and then hydrochloric acid is used. Use a chemical solution whose pH has been adjusted to slightly acidic (pH: around 6.5) using.

Then, when the spraying of the chemical solution is completed, the mixture is left for a predetermined time (step S7). In this embodiment, it is left for 2 to 3 hours. The atomizer 21 may be removed from the ceiling during the leaving period. In this case, when the atomizer 21 is removed, the opening h1 is covered again with the covering member 35.
Then, after the leaving period ends, the ceiling is disassembled (step S8). Specifically, the room including the ceiling is dismantled by removing the ceiling plate.

FIG. 6 shows the amount of mold present in the ceiling before and after the above-mentioned mist spraying. By spraying mist, the amount of mold was reduced to 10% or less, and a high mold removing effect (90% or more) could be obtained.

(Calculation method of chemical amount and leaving time)
Next, with reference to FIGS. 7 to 11, the experiment and the experimental result for specifying the amount of the chemical solution and the leaving time by the above-mentioned mist spraying will be described.

In the experiment, two areas of the attic were used.
As shown in FIG. 7A, the attic CS is a space of 2.9 m in width × 5.8 m in length and 0.6 m in height. Further, as shown in FIG. 7B, the attic CL is a space of 5.8 m in length and width and 0.6 m in height, respectively. Then, the atomizer M1 was placed in the center of the attic CS and CL, and the position P1 in the center of the room, the position P2 near the corner on the corridor side, and the position P3 near the corner on the window side were set as monitoring points.

Here, the chemical solution used for spraying was prepared by diluting a 6% sodium hypochlorite solution (Purax, manufactured by Oyalux Co., Ltd.) to 0.3% to 0.5% and adjusting the concentration to near weak acidity.

As shown in FIG. 8, in a liquid-based contact sterilization test of Aspergillus mold (Aspergillus) using a 0.3% (3000 ppm) hypochlorous acid aqueous solution, 3.1 × 10 ⁶ cfu / mL. The number of bacteria in Aspergillus falls below the lower limit of detection after a contact time of 3 minutes.

Then, the chemical solution is sprayed from the sprayer 21 onto the ceiling CS and CL, and the number of molds adhering to the surface of the attic before and after mold removal by mist spraying is measured. In this case, when the number of molds after spraying the mist is reduced by 1/10 or more (90% or more of the mold removal effect) as compared with the number of molds before spraying, it is determined that the mold can be removed.

The method of measuring the number of molds adhering to the surface of the attic was carried out by the following procedure for the attic (the surface of the attic board) of each room.
-Wipe off the mold adhering to the surface area of 10 cm x 10 cm with a sterile cotton swab and collect it.
-The collected mold is suspended in a phosphate buffer solution, applied to a medium, and cultured.
-Count the number of mold colonies that have grown by culturing.

As the experimental conditions, four kinds of conditions shown in FIG. 9 were used.
Condition 1 (spray liquid amount standard group) is a condition for evaluating the mold removal possibility using the liquid amount until the relative humidity becomes 80% or more. Here, as the atomizer M1, a nebulizer having a large amount of spray liquid per hour and a large mist particle size (mist particle size: 11.2 μm, spray liquid amount per hour: 120 mL / min) was used as a standard.
Condition 2 (volume increase zone) is a condition for evaluating the influence of the size (volume) of the ceiling under condition 1.

Condition 3 (twice spraying group) is a condition for evaluating the effect of the mist particle size on the diffusivity of the drug. Here, a nozzle having a smaller mist particle size than Condition 1 (mist particle size: 8 μm, spray liquid amount per hour: 25 mL / min) is used to evaluate the diffusivity of the drug to Condition 1. In this condition 3, it was assumed that the mold could not be removed, and additional spraying was performed the next day.
Condition 4 (chemical solution concentration increase group) is a condition for evaluating the effect of the chemical solution concentration on mold removal. Here, a chemical solution having a chemical solution concentration of 0.5% to be sprayed is used.
Then, the investigation of the adhered mold under the above conditions 1 to 4 was carried out before spraying, 1 hour after spraying, 3 hours after spraying, and the next day.

As shown in FIG. 9, in the test results of mold removal under conditions 1, 2 and 4, a mold removal effect (mold removal rate of 90% or more) was obtained at all three points by the first spraying. Specifically, the antifungal effect was obtained at more than half of the locations 1 hour after the spraying, and the antifungal effect was obtained at most of the locations 3 hours after the spraying.

On the other hand, in the test result of condition 3, the corridor side and the window surface side were obtained with the antifungal effect (mold removal rate of 90% or more) by the first spraying, but the antifungal effect at one central location was insufficient. It was. The cause is that the relative humidity rise immediately after spraying is low compared to other places, and there is a possibility that it leaked from the opening formed in the ceiling. It is considered that the relative humidity increased in the second spraying and there was no leakage, and almost the same antifungal effect (87% antifungal rate) was obtained. Therefore, it is considered possible to remove mold from the ceiling by mist sterilization by covering the opening behind the ceiling without any gaps.

In addition, as a result of identifying the colonies on the plate on which the number of colonies was counted by DNA analysis, it was found that the mold observed at a high concentration in the attic was Aspergillus mold. Then, it was clarified that these molds can be removed by spraying the hypochlorous acid aqueous solution.

From the above experimental results, the opening was covered with a covering member, and a spray nozzle (mist particle size: 11.2 μm, spray liquid amount per hour: 120 mL / min) was used, and the chemical solution concentration FAC concentration was about 3000 mg / L. It was found that the attic can be removed by spraying to a relative humidity of 80 to 85% RH and curing (leaving) for 2 to 3 hours. Then, based on this result, the amount of spray liquid according to the initial relative humidity in the on-site construction was calculated.

FIG. 10 shows a relationship diagram between the amount of spray liquid and the amount of relative humidity increase (relative humidity after spraying-initial relative humidity). From this figure, it can be seen that there is a correlation between the amount of spray liquid and the amount of relative humidity increase. In winter, the relative humidity in the room and in the ceiling decreases, so it is better to increase the amount of spray liquid.
Was calculated from the approximation equation of FIG. 10, the calculation result of the spray volume per volume 1 m ³ of the ceiling corresponding to the initial relative humidity, it is shown in FIG.

Further, as the chemical solution for removing mold, a solution prepared by diluting a 6% sodium hypochlorite solution to be in the vicinity of weak acidity was used, so that chlorine gas may be generated by spraying. Therefore, when the worker performs the dismantling work after spraying, it is necessary to wait until the chlorine gas concentration drops to the maximum allowable concentration of chlorine gas (0.5 ppm) or less. Therefore, the results of measuring the chlorine gas concentration under the above-mentioned conditions 1 to 3 are shown in FIG. 11 over time. Condition 3 is the concentration of chlorine gas at the time of the second additional spraying.

Under all conditions, the chlorine gas concentration peaked at the end of chemical spraying and then gradually decreased. When the chemical solution concentration (as FAC concentration) is 2100 to 2800 mg / L, the larger the amount of the spray solution, the higher the peak value of the chlorine gas concentration. Then, in the conditions 1 and 2 (spray amount 15,24mL / ^{m 3),} 0.8~0.9ppm, the condition 3 (spraying liquid volume 75 mL / ^{m 3),} it became 3.3 ppm. From this result, it can be seen that the chlorine gas concentration increases when the amount of the spray liquid is increased. The time required for the chlorine gas to reach the maximum permissible concentration or less was 8 to 11 minutes after the start of spraying under conditions 1 and 2, and 54 minutes after the start of spraying under condition 3.
Therefore, even when the chemical solution is sprayed so that the target relative humidity is 85% using the chemical solution amount multiplied by the safety factor, chlorine is set to 2 to 3 hours after the mist is sprayed. It is considered that the gas concentration is 0.5 ppm or less.

According to this embodiment, the following effects can be obtained.
(1) In the dismantling method of the present embodiment, after mist spraying a chemical solution capable of removing mold of Aspergillus genus on the ceiling (step S6), the ceiling is dismantled (step S8). As a result, the attic where many Aspergillus molds are present is removed to reduce the Aspergillus molds, and then the dismantling is performed, so that the Aspergillus molds can be avoided from scattering. Therefore, it is possible to suppress the scattering of Aspergillus bacteria and reduce the risk of Aspergillus infection.

(2) In the dismantling method of the present embodiment, the attic is divided into sections (step S1), and mist is sprayed on each of the divided areas (sections) (step S6). As a result, the chemical solution can be sprayed on the ceiling of the object to be dismantled to remove mold.

(3) In the dismantling method of the present embodiment, the temperature and humidity of the ceiling are measured (step S3), and the amount of the chemical spray is determined according to the temperature and humidity (step S4). As a result, mold of the genus Aspergillus can be reduced by using an appropriate amount of mold remover.

(4) In the disassembling method of the present embodiment, after mist spraying (step S6), the mixture is left for a predetermined time (2 to 3 hours) (step S7). As a result, it is possible to reduce the mold of the genus Aspergillus in the ceiling and reduce the influence of the mold remover on the human body.

(5) In the disassembling method of the present embodiment, in the installation of the mist sterilizing device (step S5), the opening h1 was covered with the covering member 35. As a result, leakage of spray from the opening h1 formed in the ceiling can be suppressed.
(6) In the disassembling method of the present embodiment, mist spraying is performed using a sprayer 21 provided with a plurality of two-fluid nozzles 22 (step S6). As a result, the chemical solution for removing mold can be sprayed with a mist of fine particles, so that the chemical solution can be evenly distributed over a wide range.

Moreover, the said embodiment may be changed as follows.
-In the above embodiment, a nebulizer 21 having two two-fluid nozzles 22 having spray ports for spraying chemicals in opposite directions is used. The device provided with the nozzle used for mist spraying is not limited to the configuration of the sprayer 21. For example, it is also possible to use a device provided with a two-fluid nozzle or a one-fluid nozzle having spray ports in four directions.

-In the above embodiment, after mist spraying (step S6), the mixture was left for 2 to 3 hours (step S7). The time to leave it as long as it is longer than the time that the dismantling worker can work, such as sufficiently reducing the mold of the genus Aspergillus by the fungicide and the concentration of chlorine gas is below the permissible range. Further, a chlorine gas sensor may be installed in the room to measure the concentration of chlorine gas in real time to determine the leaving time.

-In the above embodiment, as the chemical solution (mold remover) used for removing mold, a solution prepared by diluting a sodium hypochlorite solution to be in the vicinity of weak acidity was used. The chemical solution may be any chemical solution capable of removing mold of the genus Aspergillus, and for example, a solution obtained by simply diluting this sodium hypochlorite, peracetic acid, hydrogen peroxide solution, or the like can be used. In this case, molds of the genus Aspergillus are more resistant to chemicals than hygroscopic molds such as bacteria and black mold, so a higher concentration of chemical solution is used than when eradicating bacteria and hygroscopic molds. To do.

-In the above embodiment, a chemical solution was sprayed as a method for removing mold of the genus Aspergillus. Any method that can remove mold of the genus Aspergillus before dismantling the ceiling is not limited to spraying, for example, fumigation treatment with chemicals, mold removal by generating gas such as hydrogen peroxide and ozone, and removal by heated steam. A combination of these, such as mold and ultraviolet irradiation, can be used.

C1 ... Corridor, CL, CS ... Attic, h1 ... Opening, 20 ... Mist sterilizer, P1, P2, P3 ... Position, R1, R2 ... Room, A11, A21, A22, A23, A31, A32 ... Area , M1,21 ... Atomizer, 22 ... Two-fluid nozzle, 26 ... Chemical tank, 27 ... Air tank, 28 ... Compressor, 30 ... Support, 31 ... Support member, 35 ... Coating member.

Claims (5)

In the demolition method of dismantling at least a part of the building
The humidity of the ceiling of the target area for dismantling is measured, and the amount of the fungicide to be sprayed is specified according to the measured humidity.
A dismantling method characterized by disassembling the ceiling member constituting the attic after performing a mold removal treatment for sterilizing the mold on the attic by spraying the mold removing liquid on the attic. .. After spraying the removal fungus liquid was allowed to stand predetermined time or longer, disassembling method of claim 1, wherein the performing dismantling of the ceiling member. After dividing into compartment areas for spraying the mold remover according to the area and wall arrangement of the target area for dismantling,
The dismantling method according to claim 1 or 2 , wherein the mold removing liquid is sprayed for each of the compartment areas. An opening is formed in the ceiling of the target area for dismantling.
A sprayer for spraying the mold remover is placed behind the ceiling through the opening.
The dismantling method according to any one of claims 1 to 3 , wherein the mold removing liquid is sprayed from the sprayer onto the ceiling after closing the opening. The dismantling method according to any one of claims 1 to 4 , wherein the mold removing liquid is sprayed using a two-fluid nozzle.

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