Space decontamination method and space decontamination device

Abstract

Provided is a space decontamination method wherein a mixed gas containing air and acetic acid is supplied to a space, and an aqueous solution containing hydrogen peroxide is used to humidify the space. Also provided is a space decontamination device comprising a mixed gas supply unit and a humidification unit. The mixed gas supply unit supplies a mixed gas containing air and acetic acid to a space. The humidification unit uses an aqueous solution containing hydrogen peroxide to humidify the space. The mixed gas supply unit produces the mixed gas by, for example, by feeding air into an acetic acid solution to perform bubbling.

Description

Space decontamination method and space decontamination device CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This international application claims priority based on Japanese Patent Application No. 2023-108419, filed with the Japan Patent Office on June 30, 2023, the entire contents of which are incorporated herein by reference.

[0002] The present disclosure relates to a space decontamination method and a space decontamination apparatus.

[0003] There are spaces that need to be decontaminated in pharmaceutical manufacturing plants, biohazard facilities, cell culture processing facilities, etc. A decontamination method is disclosed in Patent Document 1. One decontamination method involves spraying a solution containing peracetic acid into the space using a spray device.

[0004] Special Publication No. 2005-526557

[0005] A space decontamination method that provides a higher decontamination effect is desired. In one aspect of the present disclosure, it is preferable to provide a space decontamination method and space decontamination device that provide a higher decontamination effect.

[0006] One aspect of the present disclosure is a space decontamination method that supplies a mixed gas containing air and acetic acid to a space and humidifies the space using an aqueous solution containing hydrogen peroxide. This space decontamination method has a high decontamination effect.

[0007] Another aspect of the present disclosure is a space decontamination apparatus including a mixed gas supply unit configured to supply a mixed gas containing air and acetic acid to a space, and a humidification unit configured to humidify the space using an aqueous solution containing hydrogen peroxide. The space decontamination apparatus according to another aspect of the present disclosure has a high decontamination effect.

[0008] 1 is an explanatory diagram showing the configuration of a mixed gas supply unit. FIG. 2 is a block diagram showing the configuration of a spatial decontamination apparatus. FIG. 3 is an explanatory diagram showing a small booth and a spatial decontamination apparatus. FIG. 4 is a graph showing the changes in acetic acid concentration, hydrogen peroxide concentration, temperature, and humidity in Example 1. FIG. 5 is a graph showing the changes in acetic acid concentration, temperature, and humidity in Comparative Example 1. FIG. 6 is an explanatory diagram showing a safety cabinet and a spatial decontamination apparatus. FIG. 7 is an explanatory diagram showing the air circulation path in a safety cabinet and the installation location of a BI. FIG. 8 is a graph showing the changes in acetic acid concentration, hydrogen peroxide concentration, temperature, and humidity in Example 2. FIG. 9 is a graph showing the changes in hydrogen peroxide concentration, temperature, and humidity in Comparative Example 2. FIG. 10 is an explanatory diagram showing a clean room and a spatial decontamination apparatus. FIG. 11 is a graph showing the changes in acetic acid concentration, hydrogen peroxide concentration, temperature, and humidity in Example 3. FIG. 12 is a graph showing the changes in hydrogen peroxide concentration, temperature, and humidity in Comparative Example 3. FIG. 13 is an explanatory diagram showing a microbiology testing room and a spatial decontamination apparatus. 10 is a graph showing the changes in acetic acid concentration, hydrogen peroxide concentration, temperature, and humidity in Example 4.

[0009] 1...mixed gas supply unit, 13...container, 15...trap, 17, 19, 21...piping, 17A...tip, 18...air, 20...safety cabinet, 23...first solution, 25...mixed gas, 101...space decontamination device, 103...humidification unit, 105...space, 107...control unit, 107A...CPU, 107B...memory, 109...information acquisition unit, 111...small booth, 201...safety cabinet, 203... Work table, 205...work space, 207...front opening, 209...fan room, 211...ceiling exhaust port, 215...circulation fan, 217, 219...duct, 221...rear passage, 223...air pump, 225...circulator fan, 301...clean room, 303...anteroom, 305...door, 307...dehumidifier, 309...dehumidifier terminal box, 401...microbiology testing room, 403, 405...laboratory table, 407...sink

[0010] Exemplary embodiments of the present disclosure will now be described with reference to the drawings.

[0011] 1. Space Decontamination Method The space decontamination method of the present disclosure decontaminates a space. The space is, for example, a space found in a pharmaceutical manufacturing plant, a biohazard facility, a cell culture processing facility, etc. The space is, for example, a space inside a safety cabinet, an isolator, a restricted access barrier system, etc. The space is, for example, a space in a clean area or a space in a sterile operation area. The space in a clean area or a space in a sterile operation area is, for example, found in a food factory, etc. The space includes, for example, a wall, floor, ceiling, or facility equipment at the boundary between the space and other areas.

[0012] Decontamination means reducing the number of microorganisms present in a space. For example, decontamination means reducing the number of microorganisms present in a space to a predetermined bacterial count level. For example, decontamination means reducing the BI by 6 logs or more. BI stands for Biological Indicator, and refers to indicator bacteria.

[0013] In the space decontamination method of the present disclosure, a mixed gas containing air and acetic acid is supplied to a space. In the space decontamination method of the present disclosure, for example, a mixed gas is generated by supplying air into a solution containing acetic acid (hereinafter referred to as the first solution) and bubbling it. The first solution is, for example, an aqueous solution of acetic acid. The concentration of acetic acid in the first solution is preferably 5 w / v% or more and 50 w / v% or less. When the concentration of acetic acid in the first solution is 5 w / v% or more, the effect of decontaminating the space is higher. When the concentration of acetic acid in the first solution is 50 w / v% or less, safety when performing the space decontamination method is higher. For example, a solution containing peracetic acid and hydrogen peroxide is excluded from the first solution even if it contains acetic acid. In other words, a solution containing acetic acid, peracetic acid, and hydrogen peroxide, for example, does not fall under the category of the first solution.

[0014] The mixed gas may further contain water vapor in addition to air and acetic acid. As a method for generating and supplying the mixed gas to a space, there is a method using a mixed gas supply unit 1 shown in FIG.

[0015] The mixed gas supply unit 1 includes a flow meter 11, a container 13, a trap 15, and pipes 17, 19, and 21. The pipe 17 sends air 18 supplied from an air supply source (not shown) to the inside of the container 13 via the flow meter 11. The flow meter 11 measures and displays the flow rate of the air 18 sent into the inside of the container 13. The flow rate of the air 18 is, for example, 1 L / min or more and 5 L / min or less.

[0016] A first solution 23 is contained inside the container 13. A tip 17A of the pipe 17 is located in the first solution 23. Therefore, bubbling occurs due to the air 18 coming out of the tip 17A. A mixed gas 25 is generated in the portion of the container 13 above the liquid surface of the first solution 23. The mixed gas 25 is made up of air bubbles that have passed through the first solution 23. The mixed gas 25 contains air and acetic acid. The mixed gas 25 also contains a small amount of water vapor.

[0017] The mixed gas 25 flows from the container 13 through the pipe 19 to the trap 15. The trap 15 is an empty container. In the trap 15, any water droplets that occur are removed from the mixed gas 25. The mixed gas 25 flows from the trap 15 through the pipe 21 to the space 105 that is the target of the space decontamination method.

[0018] In the space decontamination method of the present disclosure, the space 105 is humidified using an aqueous solution containing hydrogen peroxide (hereinafter referred to as the second solution). The concentration of hydrogen peroxide in the second solution is preferably 2 w / v% or more and 6 w / v% or less. When the concentration of hydrogen peroxide is 2 w / v% or more, the effect of decontaminating the space 105 is even greater. When the concentration of hydrogen peroxide is 6 w / v% or less, safety when performing the space decontamination method is even greater.

[0019] For example, the second solution can be vaporized using a humidifier to humidify the space 105. A commercially available product can be used as the humidifier. Humidifiers of various types include ultrasonic, steam, evaporative, and hybrid types.

[0020] For example, the space 105 can be humidified by spraying the second solution using a sprayer, a spray nozzle, or a humidifier. Examples of the sprayer include an electric sprayer used to spray a disinfectant. Examples of the humidifier include an ultrasonic humidifier.

[0021] When performing the space decontamination method of the present disclosure, the humidity of the space 105 is preferably 60% RH or higher and 80% RH or lower. When the humidity of the space 105 is 60% RH or higher, the effect of decontaminating the space 105 is higher. When the humidity of the space 105 is 80% RH or lower, condensation can be further suppressed.

[0022] When performing the space decontamination method of the present disclosure, for example, a humidity sensor can be used to measure the humidity of the space 105. For example, the humidity of the space 105 can be adjusted based on the measured humidity value. For example, the humidity of the space 105 can be adjusted by controlling a humidifier or a nozzle based on the measured humidity value.

[0023] When performing the space decontamination method of the present disclosure, the concentration of acetic acid in the space 105 is preferably 10 ppm or more and 100 ppm or less, and more preferably 10 ppm or more and 70 ppm or less. When the concentration of acetic acid in the space 105 is 10 ppm or more, the effect of decontaminating the space 105 is even greater. When the concentration of acetic acid in the space 105 is 100 ppm or less, gas treatment after decontamination is simplified. When the concentration of acetic acid in the space 105 is 70 ppm or less, gas treatment after decontamination is further simplified. The greater the amount of mixed gas 25 supplied to the space 105, the higher the concentration of acetic acid in the space 105. The higher the concentration of acetic acid in the first solution 23, the higher the concentration of acetic acid in the space 105. The method for measuring the concentration of acetic acid in the space 105 is a measurement method using a detector tube.

[0024] When performing the space decontamination method of the present disclosure, the concentration of hydrogen peroxide in the space 105 is preferably 10 ppm or more and 60 ppm or less. When the concentration of hydrogen peroxide in the space 105 is 10 ppm or more, the effect of decontaminating the space 105 is higher. When the concentration of hydrogen peroxide in the space 105 is 60 ppm or less, safety when performing the space decontamination method is higher. The higher the concentration of hydrogen peroxide in the second solution, the higher the concentration of hydrogen peroxide in the space 105. The more humidification using the second solution is promoted, the higher the concentration of hydrogen peroxide and humidity in the space 105.

[0025] The method for measuring the concentration of hydrogen peroxide in the space 105 is controlled potential electrolysis. A controlled potential electrolysis portable gas detector is used to measure the concentration of hydrogen peroxide. In the space decontamination method of the present disclosure, for example, the mixed gas 25 is supplied to the space 105 while the second solution is used to humidify the space 105. In this case, the decontamination effect of the space 105 is further enhanced.

[0026] When the spatial decontamination method of the present disclosure is performed, the concentration of peracetic acid in the space 105 is preferably 1 ppm or less. In this case, safety when performing the spatial decontamination method is further increased.

[0027] 2. Space decontamination apparatus 101 The space decontamination apparatus 101 of the present disclosure has, for example, the configuration shown in Fig. 2. The space decontamination apparatus 101 includes a mixed gas supply unit 1. The mixed gas supply unit 1 generates a mixed gas 25 containing air and acetic acid, and supplies the mixed gas 25 to a space 105.

[0028] An example of the mixed gas supply unit 1 is shown in Fig. 1. The configuration of the mixed gas supply unit 1 shown in Fig. 1 is the same as that described in the section "1. Space decontamination method" above.

[0029] The space decontamination apparatus 101 of the present disclosure is used, for example, to perform the space decontamination method of the present disclosure. The first solution 23 and the mixed gas 25 are, for example, those described in the section "1. Space decontamination method" above.

[0030] The space decontamination apparatus 101 includes a humidification unit 103. The humidification unit 103 humidifies the space 105 using a second solution. The humidification unit 103 humidifies the space 105 by vaporizing the second solution using, for example, a humidifier. A commercially available product can be used as the humidifier. Examples of the type of humidifier include ultrasonic, steam, vaporization, and hybrid types. The second solution is, for example, the one described in the above section "1. Space decontamination method."

[0031] The humidifying unit 103 humidifies the space 105 by spraying the second solution using, for example, a sprayer, a spray nozzle, or a humidifier. Examples of the sprayer include an electric sprayer used to spray a disinfectant. Examples of the humidifier include an ultrasonic humidifier.

[0032] The spatial decontamination apparatus 101 further includes a control unit 107 configured to control, for example, at least one of the mixed gas supply unit 1 and the humidification unit 103. The control unit 107 includes a microcomputer having a CPU 107A and a semiconductor memory such as a RAM or a ROM (hereinafter referred to as memory 107B).

[0033] Each function of the control unit 107 is realized by the CPU 107A executing a program stored in a non-transitory physical recording medium. In this example, the memory 107B corresponds to the non-transitory physical recording medium storing the program. Furthermore, the execution of this program results in the execution of a method corresponding to the program. Note that the control unit 107 may include one microcomputer or multiple microcomputers.

[0034] The spatial decontamination apparatus 101 further includes, for example, an information acquisition unit 109. The information acquisition unit 109 is configured to acquire information (hereinafter referred to as spatial information) representing one or more selected from the group consisting of the humidity of the space 105, the temperature of the space 105, the concentration of acetic acid in the space 105, and the concentration of hydrogen peroxide in the space 105. The information acquisition unit 109 includes, for example, a sensor capable of detecting the spatial information.

[0035] The control unit 107 controls at least one of the mixed gas supply unit 1 and the humidification unit 103 based on, for example, the spatial information acquired by the information acquisition unit 109 .

[0036] The control unit 107 controls the humidification unit 103 based on, for example, the space information acquired by the information acquisition unit 109, thereby setting the humidity of the space 105 to 60% RH or more and 80% RH or less. When the humidity of the space 105 is 60% RH or more, the effect of decontaminating the space 105 is even greater. When the humidity of the space 105 is 80% RH or less, condensation can be further suppressed, and when the humidity of the space 105 is 75% RH or less, condensation can be particularly suppressed.

[0037] The control unit 107 controls the mixed gas supply unit 1 based on, for example, the space information acquired by the information acquisition unit 109, thereby setting the concentration of acetic acid in the space 105 to 10 ppm or more and 100 ppm or less. When the concentration of acetic acid in the space 105 is 10 ppm or more, the effect of decontaminating the space 105 is even greater. When the concentration of acetic acid in the space 105 is 100 ppm or less, gas treatment after decontamination is simplified. The control unit 107 sets the concentration of acetic acid in the space 105 to 10 ppm or more and 70 ppm or less, for example. When the concentration of acetic acid in the space 105 is 70 ppm or less, gas treatment after decontamination is even more simplified.

[0038] The control unit 107 controls the humidification unit 103 based on the space information acquired by the information acquisition unit 109, for example, to set the hydrogen peroxide concentration in the space 105 to 10 ppm or more and 100 ppm or less. When the hydrogen peroxide concentration in the space 105 is 10 ppm or more, the effect of decontaminating the space 105 is even greater. When the hydrogen peroxide concentration in the space 105 is 100 ppm or less, safety when performing the space decontamination method is even higher. The control unit 107 sets the hydrogen peroxide concentration in the space 105 to 10 ppm or more and 70 ppm or less, for example. When the hydrogen peroxide concentration in the space 105 is 70 ppm or less, safety when performing the space decontamination method is especially high.

[0039] The space decontamination apparatus 101 of the present disclosure, for example, supplies the mixed gas to the space 105 and simultaneously humidifies the space 105 using the second solution. In this case, the effect of decontaminating the space 105 is further enhanced.

[0040] The space decontamination apparatus 101 of the present disclosure further includes, for example, a dehumidification unit. The dehumidification unit reduces the humidity in the space 105. For example, by reducing the humidity in the space 105 with the dehumidification unit while humidifying with the humidification unit 103, it is possible to increase the concentration of hydrogen peroxide in the space 105 while suppressing the humidity in the space 105. For example, the control unit 107 can control the dehumidification unit based on the space information so that the humidity and hydrogen peroxide concentration in the space 105 are within suitable ranges.

[0041] For example, the space decontamination method can be carried out after using a dehumidifying unit to dehumidify the space 105. Also, for example, the space decontamination method can be carried out while using the dehumidifying unit to dehumidify the space 105. The dehumidifying unit may be operated intermittently or continuously.

[0042] 3. Effects of the Space Decontamination Method and Space Decontamination Apparatus 101 (1A) The space decontamination method and space decontamination apparatus 101 of the present disclosure have a high decontamination effect.

[0043] (1B) By using the space decontamination method and space decontamination apparatus 101 disclosed herein, the space 105 can be effectively decontaminated while suppressing the humidity of the space 105. The reason for this is as follows: The mixed gas 25 contains a large amount of acetic acid but a small amount of water vapor. Therefore, by supplying the mixed gas 25 to the space 105, the concentration of acetic acid in the space 105 can be increased while suppressing the humidity of the space 105. Furthermore, by humidifying the space 105 using the second solution, the humidity of the space 105 can be appropriately increased and the concentration of hydrogen peroxide in the space 105 can be increased. By suppressing humidification using the second solution, the humidity of the space 105 can be suppressed without reducing the concentration of acetic acid in the space 105. As a result, the space 105 can be effectively decontaminated by the synergistic effect of acetic acid and hydrogen peroxide while suppressing the humidity of the space 105.

[0044] (1C) The spatial decontamination method of the present disclosure is safer than decontamination methods using peracetic acid or formaldehyde. Furthermore, the spatial decontamination method of the present disclosure can suppress the concentration of hydrogen peroxide in the space 105 while maintaining the decontamination effect. Therefore, gas treatment after decontamination is simple and easy.

[0045] (1D) Acetic acid and hydrogen peroxide decompose in a short time, so even if a gas containing acetic acid and hydrogen peroxide leaks out of the space 105, safety is high.

[0046] (1E) A gas containing acetic acid and hydrogen peroxide has high permeability. Therefore, even if there is a part in the space 105 where air circulation is difficult, that part can be decontaminated.

[0047] 4. Examples (4-1) Example 1 A small booth 111 shown in Figure 3 was prepared. The capacity of the small booth 111 was 1 m 3 The interior of the small booth 111 corresponds to the space 105. Inside the small booth 111, a mixed gas supply unit 1, a circulator fan 225, a humidifying unit 103, an information acquisition unit 109, and a dehumidifier 307 were installed.

[0048] The mixed gas supply unit 1 was equipped with an air pump 223. The air pump 223 took in air 18 from inside the small booth 111 and supplied the taken-in air 18 to the flow meter 11. The flow rate of the air 18 was 5 L / min. The first solution 23 was an aqueous solution of acetic acid with a concentration of 6 w / v %. The amount of the first solution 23 was 40 ml.

[0049] The position from which the mixed gas supply unit 1 supplied the mixed gas 25 was in front of the circulator fan 225. The mixed gas 25 supplied by the mixed gas supply unit 1 was diffused by the wind generated by the circulator fan 225.

[0050] The humidifying unit 103 was a humidifier. The humidifying unit 103 humidified the inside of the small booth 111. The second solution was an aqueous solution of hydrogen peroxide with a concentration of 2 w / v %.

[0051] In this embodiment, the information acquisition unit 109 was a temperature and humidity sensor. The information acquisition unit 109 detected the temperature and humidity of the air inside the small booth 111 and sent the detection results to the control unit 107. The control unit 107 controlled the humidification unit 103 based on the temperature and humidity measurement results. The control unit 107 controlled the humidity inside the small booth 111 to about 75% RH.

[0052] The BI was placed at the location P1 shown in Figure 3. P1 was located near the center of the small booth 111. The BI was an indicator bacterium (Geobacillus stearothermophilus (ATCC#12980)) manufactured by Mesa Labs, product number HMV-091. The bacterial count of the BI was 1 x 10 6 That was it. The BI was for hydrogen peroxide.

[0053] The space decontamination method was carried out by supplying mixed gas 25 from mixed gas supply unit 1 and humidifying it with humidification unit 103. Figure 4 shows the changes in the concentration of hydrogen peroxide, concentration of acetic acid, temperature, and humidity inside small booth 111 while the space decontamination method was being carried out. The horizontal axis of Figure 4 represents the elapsed time from the time when humidification and supply of mixed gas 25 started.

[0054] When the spatial decontamination method was carried out, the dehumidifier 307 was operated continuously. When the humidity was controlled to about 75% RH while the dehumidifier 307 was operating continuously, the amount of spray from the humidifier unit 103 increased compared to when the dehumidifier 307 was not operating. Although the airborne life of hydrogen peroxide is short, increasing the amount of spray from the humidifier unit 103 makes it possible to increase the concentration of hydrogen peroxide in the small booth 111.

[0055] The BI was removed from position P1 when the decontamination time was 70 minutes, 80 minutes, and 90 minutes, respectively. The decontamination time is the time elapsed from the time when the humidity inside the small booth 111 reached 75% RH. Next, the removed BI was cultured in a dedicated culture medium at an appropriate temperature for 7 days, and it was confirmed whether it was negative or positive. A negative result means that the BI was dead. A positive result means that the BI was not dead. The confirmation results are shown in Table 1.

[0056] The BI taken at 90 minutes of decontamination time was negative. This result confirmed that a decontamination level of 6 log or more could be achieved by 90 minutes of decontamination. During the period from 50 to 90 minutes of decontamination time, the average concentration of acetic acid inside the small booth 111 was 17 ppm, and the average concentration of hydrogen peroxide was 31 ppm.

[0057] It should be noted that the concentration of peracetic acid inside the small booth 111 was measured while the spatial decontamination method was being carried out. The method for measuring the concentration of peracetic acid was to collect a sample using an impinger and measure the concentration of peracetic acid in the collected sample using MTS oxidation GC-FID analysis. The concentration of peracetic acid was below the lower limit of detection, 0.04 ppm. Therefore, it was confirmed that peracetic acid did not contribute to decontamination. In the examples described below, the concentration of peracetic acid was also below the lower limit of detection.

[0058] (4-2) Comparative Example 1 Decontamination was basically carried out in the same manner as in Example 1. However, in Comparative Example 1, the second solution was pure water instead of an aqueous solution of hydrogen peroxide. Therefore, in Comparative Example 1, hydrogen peroxide was not supplied to the inside of the small booth 111. Also, in Comparative Example 1, the first solution 23 was an aqueous solution of acetic acid with a concentration of 12 w / v %.

[0059] Figure 5 shows the changes in acetic acid concentration, temperature, and humidity inside the small booth 111 during the spatial decontamination method. The horizontal axis of Figure 5 represents the elapsed time from the start of humidification and the supply of the mixed gas 25. The BI was removed from position P1 when the decontamination time was 90 minutes and 180 minutes, respectively. The decontamination time is the elapsed time from the time when the humidity inside the small booth 111 reached 75% RH. Next, the removed BI was cultured in a dedicated culture medium at an appropriate temperature for 7 days to determine whether it was negative or positive. The results of the confirmation are shown in Table 2.

[0060] As shown in Table 2, all BIs were positive and not killed. During the decontamination time period of 60 to 180 minutes, the average concentration of acetic acid inside the small booth 111 was 64 ppm, which was significantly higher than the average concentration in Example 1, but the decontamination effect was low. This result indicates that decontamination is difficult when only acetic acid is supplied to the space 105.

[0061] (4-3) Example 2 A safety cabinet 201 shown in Figures 6 and 7 was prepared. The safety cabinet 201 is used, for example, in biohazard facilities that handle highly infectious microorganisms. The safety cabinet 201 is also used, for example, in cell processing that requires sterility in technical fields such as regenerative medicine.

[0062] The safety cabinet 201 is a device that requires a high decontamination level of, for example, 6 log or more. The interior of the safety cabinet 201 corresponds to the space 105. The opening width of the safety cabinet 201 was 1.3 m. The safety cabinet 201 was a Class II cabinet for biohazard prevention.

[0063] The safety cabinet 201 includes a work table 203. A work space 205 is located above the work table 203. The safety cabinet 201 includes a front opening 207. When viewed from the front, the work space 205 is located at the back of the front opening 207. The safety cabinet 201 includes a fan room 209, a ceiling exhaust port 211, and a HEPA 213.

[0064] As shown in Figures 6 and 7, a circulation fan 215 installed outside the safety cabinet 201 was connected to the front opening 207 by a duct 217. In addition, a ceiling exhaust port 211 and the circulation fan 215 were connected by a duct 219. The front opening 207 was sealed with masking tape and a PVC panel except for the portion connected to the duct 217. In addition, the ceiling exhaust port 211 was sealed with masking tape and a PVC panel except for the portion connected to the duct 219. Other gaps in the safety cabinet 201 were also sealed with masking tape.

[0065] When the circulation fan 215 is operated, air circulates along the path indicated by the arrows in Fig. 7. Air in the work space 205 passes from the front opening 207 through the duct 217, the circulation fan 215, the duct 219, and the ceiling exhaust port 211 in this order, before entering the fan room 209. Some of the air in the fan room 209 passes through the HEPA 213 and enters the work space 205. Some of the air in the fan room 209 passes through the rear passage 221 and enters the work space 205 from the rear side of the work table 203.

[0066] As shown in Fig. 6, a mixed gas 25 generated in a mixed gas supply unit 1 was supplied to a working space 205. The mixed gas supply unit 1 was equipped with an air pump 223. The air pump 223 took in air 18 from the working space 205 and supplied the taken-in air 18 to a flow meter 11. The flow rate of the air 18 was 5 L / min. The first solution 23 was an aqueous solution of acetic acid with a concentration of 40 w / v %. The amount of the first solution 23 was 40 ml.

[0067] As shown in Fig. 6, a circulator fan 225 was installed on the workbench 203. The position from which the mixed gas 25 was supplied was in front of the circulator fan 225. The mixed gas 25 supplied by the mixed gas supply unit 1 was diffused by the wind generated by the circulator fan 225 and sent to the duct 217.

[0068] As shown in FIG. 6 , the humidifying unit 103 was placed on a workbench 203, and the work space 205 was humidified by the humidifying unit 103. The second solution was an aqueous solution of hydrogen peroxide with a concentration of 3 w / v %. In this example, the information acquisition unit 109 was a temperature and humidity sensor. The information acquisition unit 109 detected the temperature and humidity of the air at the ceiling exhaust port 211 and sent the detection results to the control unit 107. The control unit 107 controlled the humidifying unit 103 based on the temperature and humidity measurement results. The control unit 107 controlled the humidity inside the safety cabinet 201 to about 75% RH.

[0069] BIs were installed at locations P1 to P4 shown in Figure 7. P1 was located on the HEPA 213 side of the work space 205. P2 was located at the lower side inside the back passage 221. P3 was located at the perforated metal provided at the ceiling exhaust port 211. P4 was located below the workbench 203.

[0070] The BI was Geobacillus stearothermophilus (ATCC#12980). The bacterial count of the BI was 1 x 10 6 That was all. Decontamination was started in the safety cabinet 201 with the air circulating as shown in Fig. 7. Decontamination involves supplying mixed gas 25 from the mixed gas supply unit 1 and humidifying it with the humidification unit 103. Fig. 8 shows the changes in the acetic acid concentration, hydrogen peroxide concentration, temperature, and humidity inside the safety cabinet 201 during decontamination. The horizontal axis of Fig. 8 represents the elapsed time from the time when humidification and the supply of mixed gas 25 were started.

[0071] When the decontamination time was 120 minutes, BIs were removed from P1, P2, and P3, respectively. The decontamination time was the time elapsed from the time the humidity inside the safety cabinet 201 reached 75% RH. Furthermore, when the decontamination time was 60 minutes, 75 minutes, 90 minutes, 105 minutes, and 120 minutes, BIs were removed from P4, respectively. Next, the removed BIs were cultured in a dedicated medium at an appropriate temperature for 7 days and confirmed to be negative or positive. The confirmation results are shown in Table 3. Note that three BIs were removed under one condition. A condition is a combination of the location of the BI and the decontamination time when the BI was removed. If two or more of the three BIs were negative, the decontamination under that condition was determined to be successful.

[0072] As shown in Table 3, decontamination was successful at all locations P1 to P4 and at all decontamination times.

[0073] (4-4) Comparative Example 2 Decontamination was basically carried out in the same manner as in Example 2. However, in Comparative Example 2, the mixed gas 25 was not supplied to the working space 205. That is, in Comparative Example 2, acetic acid was not supplied to the working space 205. A BI was installed at the location P4.

[0074] 9 shows the transition of the hydrogen peroxide concentration, temperature, and humidity inside the safety cabinet 201 during decontamination. The horizontal axis of FIG. 9 represents the elapsed time from the time when humidification started.

[0075] When the decontamination time was 150 minutes, BIs were removed from P1, P2, and P3, respectively. The decontamination time is the elapsed time from when the humidity inside the safety cabinet 201 reached 75% RH. Furthermore, when the decontamination time was 80 minutes, 90 minutes, 100 minutes, 110 minutes, 120 minutes, 130 minutes, 140 minutes, and 150 minutes, BIs were removed from P4, respectively. Next, the removed BIs were cultured in a dedicated medium at an appropriate temperature for 7 days, and confirmed to be negative or positive. The confirmation results are shown in Table 4. Note that only one BI was removed under each condition.

[0076] As shown in Table 4, BI was positive at all locations P1 to P4 and at all decontamination times. This result indicates that decontamination is difficult when only hydrogen peroxide is supplied to the workspace 205.

[0077] (4-5) Example 3 A clean room 301 and an antechamber 303 shown in Figure 10 were subjected to the spatial decontamination method. A door 305 was located between the clean room 301 and the antechamber 303. The door 305 was always kept open. The total volume of the clean room 301 and the antechamber 303 was approximately 34 m 3 Inside the clean room 301, a dehumidifier 307, a safety cabinet 201, and a dehumidifier terminal box 309 were installed. The safety cabinet 201 was an indoor circulation type class II cabinet for biohazard countermeasures.

[0078] Mixed gas supply unit 1, humidification unit 103, information acquisition unit 109, and circulator fan 225 were installed in clean room 301. Mixed gas supply unit 1 was located in the center of clean room 301.

[0079] The first solution 23 was an aqueous solution of acetic acid with a concentration of 40 w / v %. The amount of the first solution 23 was 150 ml. The flow rate of the air 18 was 10 L / min. The second solution was an aqueous solution of hydrogen peroxide with a concentration of 2 w / v %.

[0080] BIs were installed at locations P1 to P7 shown in Figure 10. P1 was the position of the outlet of the work space 205 of the safety cabinet 201, and was a position downstream of the HEPA 213. P2 was a position on the exhaust side of the safety cabinet 201. P3 was a position between the safety cabinet 201 and its rear wall. P4 was inside the dehumidifier terminal box 309. Note that air is difficult to circulate between the inside and outside of the dehumidifier terminal box 309. P5 was a position on the surface of the wall of the clean room 301. P6 was a position on the surface of the wall of the antechamber 303. P7 was a position inside the clean room 301.

[0081] First, the humidity in the clean room 301 and the anteroom 303 was reduced to 50-60% RH using the dehumidifier 307. Next, the mixed gas 25 was supplied by the mixed gas supply unit 1 and humidified by the humidification unit 103, thereby carrying out the space decontamination method. While carrying out the space decontamination method, the safety cabinet 201 was operated. By operating the safety cabinet 201, the decontamination gas was circulated inside the safety cabinet 201. The decontamination gas is a gas containing acetic acid and hydrogen peroxide.

[0082] When the spatial decontamination method was performed, the humidity inside the clean room 301 and the anteroom 303 was controlled to approximately 75% RH by controlling the humidifier unit 103. When the spatial decontamination method was performed, the dehumidifier 307 operated intermittently. Note that the dehumidifier 307 may also operate continuously. When attempting to control the humidity to approximately 75% RH while the dehumidifier 307 is operating intermittently or continuously, the amount of spray from the humidifier unit 103 increases compared to when the dehumidifier 307 is not operating. Although the airborne life of hydrogen peroxide is short, increasing the amount of spray from the humidifier unit 103 can increase the concentration of hydrogen peroxide in the clean room 301 and the anteroom 303.

[0083] When the spatial decontamination method was being carried out, the air inside the clean room 301 was agitated by the circulator fan 225. The humidifying unit 103 and the mixed gas supply unit 1 were present in the path of the air blown out by the circulator fan 225.

[0084] Figure 11 shows the changes in the hydrogen peroxide concentration, acetic acid concentration, temperature, and humidity inside the clean room 301 during the implementation of the spatial decontamination method. The horizontal axis in Figure 11 represents the decontamination time. The decontamination time is the time elapsed from the time when the humidity inside the clean room 301 reached 75% RH. In the decontamination time range of 30 to 90 minutes, the average hydrogen peroxide concentration inside the clean room 301 was 42 ppm, and the average acetic acid concentration was 67 ppm.

[0085] When the decontamination time was 180 minutes, BIs were extracted from P1, P2, P3, and P4, respectively. Furthermore, when the decontamination time was 60 minutes, 90 minutes, 120 minutes, 150 minutes, and 180 minutes, BIs were extracted from P7, respectively. Next, the extracted BIs were cultured in a dedicated medium at the appropriate temperature for 7 days, and confirmed to be negative or positive. The results of the confirmation are shown in Table 5. Note that three BIs were extracted under each condition.

[0086] As shown in Table 5, all locations P1 to P4 were negative. Furthermore, P7 was negative when the decontamination time was 90 to 180 minutes. The decontamination gas in the clean room 301 flows in from the bottom of the work surface at the front of the safety cabinet 20 and splits between the exhaust port and the HEPA outlet on the work surface before reaching the clean room. The negative BIs at P1 and P2 mean that the interior of the safety cabinet 201 and the filter section through which the decontamination gas passes have also been successfully decontaminated. This confirms that the decontamination gas has high permeability and can penetrate into the filter section.

[0087] The BI in P4, an area with poor air circulation, also tested negative, indicating that the decontamination gas has high permeability.

[0088] (4-6) Comparative Example 3 A space decontamination method was carried out basically in the same manner as in Example 3. However, in Comparative Example 3, mixed gas 25 was not supplied into the clean room 301. That is, in Comparative Example 3, acetic acid was not supplied into the clean room 301.

[0089] Figure 12 shows the changes in the hydrogen peroxide concentration, acetic acid concentration, temperature, and humidity inside the clean room 301 while the spatial decontamination method was being carried out. The horizontal axis of Figure 12 represents the decontamination time. The decontamination time is the time elapsed from the time when the humidity inside the clean room 301 reached 75% RH. In the decontamination time range from 0 to 480 minutes, the average hydrogen peroxide concentration inside the clean room 301 was 22 ppm.

[0090] When the decontamination time was 480 minutes, BIs were extracted from P1, P2, P3, P4, P5, and P6. The extracted BIs were then cultured in a dedicated medium at the appropriate temperature for 7 days and confirmed to be negative or positive. The results are shown in Table 6. Note that only one BI was extracted under each condition.

[0091] As shown in Table 6, BI was positive in P1, P2, and P4.

[0092] (4-7) Example 4 The microbiology testing room 401 shown in Figure 13 was the subject of the spatial decontamination method. All entrances and windows of the microbiology testing room 401 were closed. The microbiology testing room 401 was equipped with laboratory tables 403 and 405, a sink 407, a safety cabinet 201, and a dehumidifier 307.

[0093] A mixed gas supply unit 1, two humidification units 103, an information acquisition unit 109, and a circulator fan 225 were installed in the microbiology testing room 401. The humidification unit 103 was a sprayer. The first solution 23 was an aqueous solution of acetic acid with a concentration of 40 w / v %. The amount of the first solution 23 was 150 ml. The flow rate of the air 18 was 15 L / min. The second solution was an aqueous solution of hydrogen peroxide with a concentration of 2 w / v %.

[0094] 13, BIs were installed at locations P1 to P5. BI was the same as in Example 1. P1 was the position of the outlet of the work space 205 of the safety cabinet 201, and was located downstream of the HEPA 213. P2 was located on the exhaust side of the safety cabinet 201.

[0095] Positions P3 and P5 were on the floor. Position P4 was at the far end of the thermostatic chamber (not shown). The thermostatic chamber was placed on the laboratory bench 405. The door of the thermostatic chamber was left open about 2 cm. It was difficult for air to circulate between the inside and outside of the thermostatic chamber.

[0096] The space decontamination method was carried out by supplying the mixed gas 25 from the mixed gas supply unit 1 and humidifying the mixed gas by the humidification unit 103. When the space decontamination method was carried out, the safety cabinet 201 was operated. By operating the safety cabinet 201, the decontamination gas was circulated inside the safety cabinet 201.

[0097] When the spatial decontamination method was being carried out, the humidity inside the microbiology testing room 401 was controlled to about 75% RH by controlling the humidification unit 103. When the spatial decontamination method was being carried out, the air inside the microbiology testing room 401 was agitated by the circulator fan 225. The mixed gas supply unit 1 was located in the path of the air blown out by the circulator fan 225.

[0098] Figure 14 shows the changes in the hydrogen peroxide concentration, acetic acid concentration, temperature, and humidity inside the microbiology testing room 401 during the implementation of the space decontamination method. The horizontal axis of Figure 14 represents the elapsed time from the time when humidification and the supply of the mixed gas 25 were started. In the decontamination time range of 30 to 210 minutes, the average hydrogen peroxide concentration inside the microbiology testing room 401 was 30 ppm, and the average acetic acid concentration was 35 ppm. The decontamination time is the time elapsed from the time when the humidity inside the microbiology testing room 401 reached 75% RH.

[0099] When the decontamination time was 210 minutes, BIs were extracted from P1, P2, P3, and P4, respectively. Furthermore, when the decontamination time was 90 minutes, 120 minutes, 150 minutes, 180 minutes, and 210 minutes, BIs were extracted from P5, respectively. Next, the extracted BIs were cultured in a dedicated medium at an appropriate temperature for 7 days, and confirmed to be negative or positive. The results of the confirmation are shown in Table 7. Note that three BIs were extracted under each condition.

[0100] As shown in Table 5, when the decontamination time was 120 minutes or longer, the majority of BIs were negative at every location, indicating successful decontamination. The decontamination gas in the clean room 301 flows in from the bottom of the work surface at the front of the safety cabinet 20 and splits between the exhaust port and the HEPA outlet on the work surface before reaching the clean room. The negative BIs at P1 and P2 indicate that the interior of the safety cabinet 201 and the filter section through which the decontamination gas passes have also been successfully decontaminated. This confirms that the decontamination gas has high permeability and can penetrate into the filter section.

[0101] The BI in P4, an area with poor air circulation, also tested negative, indicating that the decontamination gas has high permeability.

[0102] 5. Other Embodiments Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments and can be implemented in various modifications.

[0103] (1) In the second embodiment, the space inside a safety cabinet is decontaminated, but the present invention is not limited to this. For example, the space inside an isolator, an access restriction barrier system, etc. may also be decontaminated.

[0104] (2) The control unit 107 and the method described herein may be implemented by a special-purpose computer configured by configuring a processor and memory programmed to perform one or more functions embodied in a computer program. Alternatively, the control unit 107 and the method described herein may be implemented by a special-purpose computer configured by configuring a processor with one or more dedicated hardware logic circuits. Alternatively, the control unit 107 and the method described herein may be implemented by one or more special-purpose computers configured by combining a processor and memory programmed to perform one or more functions with a processor configured with one or more hardware logic circuits. Furthermore, the computer program may be stored as instructions executed by a computer on a computer-readable non-transitory tangible storage medium. The method for implementing the functions of each component included in the control unit 107 does not necessarily need to include software; all of the functions may be implemented using one or more hardware components.

[0105] (3) The function of one component in each of the above embodiments may be shared among multiple components, or the functions of multiple components may be performed by one component. Also, part of the configuration of each of the above embodiments may be omitted. Furthermore, at least part of the configuration of each of the above embodiments may be added to or substituted for the configuration of another of the above embodiments.

[0106] (4) In addition to the spatial decontamination apparatus 101 described above, the present disclosure can also be realized in various forms, such as a system including the spatial decontamination apparatus 101 as a component, a program for causing a computer to function as the control unit 107, a non-transitory tangible recording medium such as a semiconductor memory on which this program is recorded, and a method for manufacturing a spatial decontamination apparatus. [Technical Ideas Disclosed by this Specification] [Item 1] A spatial decontamination method comprising: supplying a mixed gas containing air and acetic acid to a space; and humidifying the space using an aqueous solution containing hydrogen peroxide. [Item 2] The spatial decontamination method according to Item 1, wherein the mixed gas is generated by supplying air into a solution containing acetic acid and bubbling it. [Item 3] The spatial decontamination method according to Item 1 or 2, wherein the humidity of the space is 60% RH or higher and 80% RH or lower during the spatial decontamination method. [Item 4] A space decontamination method according to any one of items 1 to 3, wherein, during the space decontamination method, the concentration of acetic acid in the space is 10 ppm or more and 100 ppm or less, and the concentration of hydrogen peroxide in the space is 10 ppm or more and 100 ppm or less. [Item 5] A space decontamination apparatus comprising: a mixed gas supply unit configured to supply a mixed gas containing air and acetic acid to a space, and a humidification unit configured to humidify the space using an aqueous solution containing hydrogen peroxide. [Item 6] The space decontamination apparatus according to item 5, wherein the mixed gas supply unit is configured to generate the mixed gas by supplying air into an acetic acid solution and bubbling it.

Claims

1. A method for decontaminating a space, comprising: generating a mixed gas containing air and acetic acid using a solution containing acetic acid (excluding cases where the solution contains peracetic acid and hydrogen peroxide); supplying the mixed gas to a space; and humidifying the space using an aqueous solution containing hydrogen peroxide.

2. A method for spatial decontamination according to claim 1, comprising: generating the mixed gas by supplying air into a solution containing acetic acid and bubbling the air.

3. A spatial decontamination method according to claim 1 or 2, wherein the humidity of the space is 60% RH or more and 80% RH or less when the spatial decontamination method is being performed.

4. A spatial decontamination method according to claim 1 or 2, wherein, when the spatial decontamination method is performed, the concentration of acetic acid in the space is 10 ppm or more and 100 ppm or less, and the concentration of hydrogen peroxide in the space is 10 ppm or more and 100 ppm or less.

5. A space decontamination device comprising: a mixed gas supply unit configured to supply a mixed gas containing air and acetic acid to a space; and a humidification unit configured to humidify the space using an aqueous solution containing hydrogen peroxide, wherein the mixed gas supply unit is configured to generate the mixed gas using an acetic acid solution (except when the acetic acid solution contains peracetic acid and hydrogen peroxide).

6. A spatial decontamination apparatus according to claim 5, wherein the mixed gas supply unit is configured to generate the mixed gas by supplying air into the acetic acid solution and bubbling it.

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