How to measure airtightness of building parts

Abstract

To accurately measure the airtightness of parts of a building with basic insulation. [Solution] The airtightness measurement method includes steps of setting a house 1 to a first to third states (S11, etc.), steps of measuring an airflow rate Q and a pressure difference ΔP in each state (S12, etc.), steps of calculating first to third gap areas A1 to A3 based on the airflow rate Q and the pressure difference ΔP (S13, etc.), and steps of calculating total equivalent gap areas B1 to B3 of the first to third parts of the house 1 based on the first to third gap areas A1 to A3 (S20). In S17, a third state is set in which an underfloor space 15 and an outdoor space 16 are communicated via a duct 61, a blower 22 is caused to blow air from an indoor space 14 to an outdoor space 16, and an underfloor blower 23 is caused to blow air from the outdoor space 16 to the underfloor space 15 via the duct 61. In S18, an airflow rate Q3 in the blower 22 and a pressure difference ΔP3 between the indoor space 14 and the outdoor space 16 are measured.

Description

[Technical field]

[0001] The present invention relates to a method for measuring airtightness of a building, and more particularly to a method for measuring airtightness of a part of a building whose base is insulated. [Background technology]

[0002] In order to improve energy saving performance, recent buildings are required to have high airtightness. In order to evaluate the airtightness of a building, it is necessary to measure the airtightness of the building. Regarding the measurement of the airtightness of a building, Non-Patent Document 1 describes a method of testing the airtightness of a building and its parts by generating a pressure difference between the inside and outside of the building using a blower.

[0003] Patent Document 1 describes a method for measuring the airtightness of a building by creating a pressure difference between the inside and outside of the building by using an intake and exhaust fan and a kitchen range fan that are already installed in the building to take in or exhaust air. Non-Patent Document 2 describes a method for measuring the airtightness (amount of gaps) of the foundation and base of a building with insulated foundations, by using a fan that directly exhausts air from under the floor to the outside air and a fan that exhausts air from a living room to the outside air, and measuring the pressure difference between under the floor and the outside air and the amount of air exhausted from under the floor while adjusting the flow rate of each fan so that the pressure under the floor and the room are equal. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2001-91397 A [Non-patent literature]

[0005] [Non-Patent Document 1] JIS A2201:2017 "Test method for airtightness performance of houses, etc. using fans," Japan Standards Association, November 2017 [Non-Patent Document 2] Yoshinori Homma, Masamichi Enauchi, Akira Fukushima, Hirotaka Suzuki, "Effect of Air Movement from Living Rooms and Outside Air on Temperature and Humidity Environment under Floor with Insulated Foundation," Journal of Architecture and Planning, Architectural Institute of Japan, Vol. 548, pp. 23-30, October 2001. Summary of the Invention [Problem to be solved by the invention]

[0006] In order to repair a building and increase its airtightness based on the results of measuring its airtightness, it is preferable to measure not only the airtightness of the entire building, but also the airtightness of parts of the building, such as the ceiling, walls, floors, and foundations.

[0007] Patent Document 1 describes a method for measuring the airtightness of an entire building, but does not describe a method for measuring the airtightness of parts of a building. Non-Patent Document 2 describes a method for measuring the airtightness of the foundation and base of a building with insulated foundations, but when actually implementing this method, it is difficult to adjust the flow rate of each fan so that the pressure under the floor and inside the room are equal. For this reason, the method described in Non-Patent Document 2 cannot accurately measure the airtightness of parts of a building.

[0008] The present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide a means for accurately measuring the airtightness of a part of a building whose foundation is insulated. [Means for solving the problem]

[0009] (1) An airtightness measurement method of the present invention is a method for measuring airtightness of a part of a building whose foundation is insulated, comprising: a first measurement step of measuring an airflow rate in the blower and a pressure difference between the indoor space and the outdoor space in a first state in which an indoor space and an underfloor space of the building are communicated with each other and the blower is caused to blow air from the indoor space to the outdoor space of the building; a first calculation step of calculating a first gap area based on the airflow rate and the pressure difference measured in the first measurement step; a second measurement step of measuring an airflow rate in the blower and a pressure difference between the underfloor space and the indoor space in a second state in which the indoor space and the outdoor space are communicated with each other and the blower is caused to blow air from the underfloor space to the indoor space; the first gap area based on the first gap area, the second gap area based on the pressure difference, a third measurement step of measuring the airflow rate of the blower and the pressure difference between the indoor space and the outdoor space in a third state in which the underfloor space and the outdoor space are connected via an airtight flow path, the blower is caused to blow air from the indoor space to the outdoor space, and a second blower different from the blower is caused to blow air from the outdoor space to the underfloor space via the airtight flow path, the third calculation step of calculating a third gap area based on the airflow rate and the pressure difference measured in the third measurement step, and a fourth calculation step of calculating a total equivalent gap area of ​​the first portion including the foundation of the building based on the first gap area, the second gap area, and the third gap area.

[0010] According to the above airtightness measurement method, the three gap areas are calculated based on the airflow rate and pressure difference measured in the three states, and the total equivalent gap area of ​​the first section including the foundation of the building is calculated based on the three gap areas, thereby measuring the airtightness of the first section. In the third state, air is blown from the indoor space to the outdoor space, and from the outdoor space to the underfloor space, so that the airflow rate and pressure difference can be measured in a state where the underfloor space and the outdoor space are at equal pressure. Therefore, the third gap area can be accurately calculated, and the total equivalent gap area of ​​the first section can be accurately calculated. Therefore, the airtightness of the first section of a building with a foundation insulation can be accurately measured.

[0011] (2) Preferably, in the third measuring step, the amount of air sent from the second fan may be controlled so that the underfloor space and the outdoor space are equal in pressure.

[0012] According to the above configuration, by controlling the airflow rate of the second fan so that the underfloor space and the outdoor space are at equal pressure, the airflow rate and the pressure difference can be measured in a state where the underfloor space and the outdoor space are at equal pressure. Therefore, the third gap area can be accurately calculated, and the total equivalent gap area of ​​the first portion can be accurately calculated.

[0013] (3) Preferably, in the third measurement step, the air volume of the second fan may be increased by a predetermined increment until the pressure difference between the underfloor space and the outdoor space remains less than a predetermined amount for a predetermined period of time or longer.

[0014] According to the above configuration, the airflow rate and the pressure difference between the underfloor space and the outdoor space can be measured in a state where the pressure difference between the underfloor space and the outdoor space is equalized by increasing the airflow rate of the second fan by a predetermined increment until the pressure difference between the underfloor space and the outdoor space remains less than the predetermined amount for a predetermined period of time or more. Therefore, the third gap area can be accurately calculated, and the total equivalent gap area of ​​the first portion can be accurately calculated.

[0015] (4) Preferably, in the fourth calculation step, a total equivalent gap area of ​​the first portion may be calculated by performing four arithmetic operations on the first gap area, the second gap area, and the third gap area.

[0016] According to the above configuration, the total equivalent gap area of ​​the first portion can be easily calculated by performing arithmetic operations on the three gap areas.

[0017] (5) Preferably, in the fourth calculation step, a total equivalent gap area of ​​a second portion including a ceiling and an exterior wall of the building, and a total equivalent gap area of ​​a third portion including a floor and a partition wall of the building may be further calculated based on the first gap area, the second gap area, and the third gap area.

[0018] According to the above configuration, the three gap areas are calculated based on the airflow rate and pressure difference measured in the three states, and the total equivalent gap area of ​​the second section including the ceiling and the exterior wall and the third section including the floor and the partition wall is calculated based on the three gap areas, so that the airtightness of the second section and the third section can be measured. In the third state, air is blown from the indoor space to the outdoor space and from the outdoor space to the underfloor space, so that the airflow rate and the pressure difference can be measured in a state where the underfloor space and the outdoor space are at equal pressure. Therefore, the third gap area can be accurately calculated, and the total equivalent gap area of ​​the second section and the third section can be accurately calculated. Therefore, the airtightness of the second section and the third section of a building with a foundation insulation can be accurately measured.

[0019] (6) Preferably, in the fourth calculation step, a total equivalent gap area of ​​the first portion, a total equivalent gap area of ​​the second portion, and a total equivalent gap area of ​​the third portion may be calculated by performing four arithmetic operations on the first gap area, the second gap area, and the third gap area.

[0020] According to the above configuration, the total equivalent gap area of ​​each portion can be easily calculated by performing arithmetic operations on the three gap areas.

[0021] (7) Preferably, the airtightness measurement method may further include a step of setting the building to the first state before the first measurement step, a step of setting the building to the second state before the second measurement step, and a step of setting the building to the third state before the third measurement step.

[0022] According to the above configuration, the building can be set in three states and the airflow volume and pressure difference can be measured in each state. Effect of the Invention

[0023] According to the present invention, the airtightness of a part of a building with a foundation insulation can be accurately measured. [Brief description of the drawings]

[0024] [Figure 1] FIG. 1 is a schematic cross-sectional view of a house 1 to which an airtightness measurement method according to an embodiment of the present invention is applied. [Diagram 2] FIG. 2 is a block diagram showing the configuration of an airtightness measuring device 20 used in the airtightness measuring method according to the embodiment. [Diagram 3] FIG. 3 is a diagram showing the house 1 set to the first state. [Figure 4] FIG. 4 is a diagram showing the house 1 set to the second state. [Diagram 5] FIG. 5 is a diagram showing the house 1 set in the third state. [Figure 6] FIG. 6 is a flowchart of the air tightness measurement method according to the embodiment. [Figure 7] FIG. 7 is a flowchart showing the operation of the air tightness measuring device 20. [Figure 8] Fig. 8(A) is a flowchart showing details of the measurement process shown in Fig. 7. Fig. 8(B) is a flowchart showing details of the control / measurement process shown in Fig. 7. [Figure 9] FIG. 9 is a graph showing the relationship between the pressure difference ΔP and the airflow rate Q. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] Hereinafter, an airtightness measurement method according to an embodiment of the present invention will be described with reference to the drawings. Note that the embodiment described below is merely an example of the present invention, and it goes without saying that the embodiment of the present invention can be appropriately modified without departing from the gist of the present invention.

[0026] [Outline of airtightness measurement method] The airtightness measurement method according to this embodiment is a method for measuring the airtightness of a part of a building with a basic insulation. This airtightness measurement method includes the steps of setting the building to first to third states, measuring the airflow and pressure difference in each state, calculating three gap areas based on the measured airflow and pressure difference, and calculating the total equivalent gap area of ​​the three parts of the building based on the calculated three gap areas.

[0027] [Configuration of House 1] The house 1 shown in FIG. 1 is an example of a building with foundation insulation. The house 1 includes a ceiling 2, an exterior wall 3, a floor 4, a partition wall 5, a foundation 6, and a roof 7. The exterior wall 3 has windows 11 and 12. The floor 4 has an underfloor inspection hatch 13. The ceiling 2, the exterior wall 3, and the floor 4 define an indoor space 14. The floor 4 and the foundation 6 define an underfloor space 15. The partition wall 5 is located in the indoor space 14. The roof 7 is located above the ceiling 2. Thermal insulation material 8 is provided on the indoor space 14 side of the ceiling 2 and the exterior wall 3, and on the underfloor space 15 side of the rising part of the foundation 6.

[0028] Hereinafter, the space outside the house 1 (space other than the indoor space 14 and the underfloor space 15) will be referred to as the outdoor space 16, the portion including the foundation 6 will be referred to as the "first portion," the portion including the ceiling 2 and the exterior wall 3 will be referred to as the "second portion," and the portion including the floor 4 and the partition wall 5 will be referred to as the "third portion." The underfloor space 15 will also be referred to as the foundation space.

[0029] [Configuration of air tightness measuring device 20] The airtightness measurement method according to this embodiment is performed, for example, using an airtightness measurement device 20 shown in Fig. 2. The airtightness measurement device 20 includes a main device 21, a blower 22, and an underfloor blower 23. The main device 21 includes a CPU 31, a memory 32, an input unit 33, a display unit 34, an interface unit (referred to as I / F unit in Fig. 2) 35, a flow rate sensor 36, and two differential pressure sensors 37, 38. The CPU 31 and the memory 32 function as a control unit 30.

[0030] Each component of the main device 21 is connected to a bus 39 in the main device 21. The CPU 31 controls the operations of the main device 21, the blower 22, and the underfloor blower 23. The memory 32 stores the programs executed by the CPU 31 and functions as a working memory for the CPU 31. The input unit 33 has four buttons 41 to 44. The buttons 41 to 44 correspond to a first measurement, a second measurement, a third measurement, and an evaluation, respectively. When any of the buttons 41 to 44 is pressed, the input unit 33 outputs a signal SS1 to the CPU 31 indicating that the button has been pressed and the type of the pressed button. The display unit 34 displays the airtightness measurement result and the like on a screen under the control of the CPU 31.

[0031] The blower 22 and the under-floor blower 23 are connected to an interface unit 35. The control unit 30 outputs, via the interface unit 35, to the blower 22 a signal CS1 that controls the airflow rate of the blower 22, and outputs, via the interface unit 35, to the under-floor blower 23 a signal CS2 that controls the airflow rate of the under-floor blower 23.

[0032] Four or six vinyl tubes are connected to the airtightness measuring device 20. The blower 22 is connected to the flow sensor 36 via tubes 55 and 56. One end of the tube 55 is attached to the intake side of the blower 22, and one end of the tube 56 is attached to the exhaust side of the blower 22. The other ends of the tubes 55 and 56 are connected to one end and the other end of the flow sensor 36, respectively. The flow sensor 36 measures the airflow rate in the blower 22, and outputs a signal SS2 according to the measured airflow rate.

[0033] The differential pressure sensor 37 is connected to tubes 51 and 52. The differential pressure sensor 38 is connected to tubes 53 and 54. One end of the tubes 51 and 52 is connected to one end and the other end of the differential pressure sensor 37, respectively. One end of the tubes 53 and 54 is connected to one end and the other end of the differential pressure sensor 38, respectively. The other ends E1 to E4 of the tubes 51 to 54 are in an open state. Hereinafter, the other ends E1 to E4 are referred to as open ends.

[0034] The open ends E1-E4 are arranged in either the indoor space 14, the underfloor space 15, or the outdoor space 16 depending on the type of measurement. The differential pressure sensor 37 measures the pressure difference between the space in which the open end E1 is arranged and the space in which the open end E2 is arranged, and outputs a signal SS3 according to the measured pressure difference. The differential pressure sensor 38 measures the pressure difference between the space in which the open end E3 is arranged and the space in which the open end E4 is arranged, and outputs a signal SS4 according to the measured pressure difference.

[0035] [1st to 3rd measurement] The measurer sets the house 1 in a first state (FIG. 3), a second state (FIG. 4), and a third state (FIG. 5), and measures the airflow rate and pressure difference in each state using the airtightness measuring device 20. For convenience of illustration in the drawings, the partition wall 5 is omitted in FIGS. 3 to 5.

[0036] In a first state (FIG. 3), the blower 22 is attached to the window 11, the window 12 is closed, and the underfloor inspection hatch 13 is open. The open end E1 of the tube 51 is located in the indoor space 14, and the open end E2 of the tube 52 is located in the outdoor space 16. The blower 22 blows air from the indoor space 14 to the outdoor space 16 based on an output signal CS1 of the control unit 30. The control unit 30 obtains the airflow rate Q1 of the blower 22 based on an output signal SS2 of the flow rate sensor 36, and obtains the pressure difference ΔP1 between the indoor space 14 and the outdoor space 16 based on an output signal SS3 of the differential pressure sensor 37.

[0037] In the first state, the indoor space 14 and the underfloor space 15 are communicated with each other, and the blower 22 blows air from the indoor space 14 to the outdoor space 16. In the first state, the indoor space 14 and the underfloor space 15 (dotted pattern portion) are under negative pressure, so air flows from the outdoor space 16 into the indoor space 14 and the underfloor space 15 through the gap in the first portion including the foundation 6 and the gap in the second portion including the ceiling 2 and the exterior wall 3. In this state, the airflow rate Q1 in the blower 22 and the pressure difference ΔP1 between the indoor space 14 and the outdoor space 16 are measured. The first measurement is the same as the measurement described in Non-Patent Document 1. In the first measurement, the underfloor blower 23 and the differential pressure sensor 38 are not used.

[0038] In the second state (FIG. 4), the window 11 is closed, the window 12 is open, and the blower 22 is attached to the underfloor inspection hatch 13. Note that the window 11 may be open. The open end E1 of the tube 51 is disposed in the underfloor space 15, and the open end E2 of the tube 52 is disposed in the indoor space 14. The blower 22 blows air from the underfloor space 15 to the indoor space 14 based on an output signal CS1 of the control unit 30. The control unit 30 obtains the airflow rate Q2 of the blower 22 based on an output signal SS2 of the flow rate sensor 36, and obtains the pressure difference ΔP2 between the underfloor space 15 and the indoor space 14 based on an output signal SS3 of the differential pressure sensor 37.

[0039] In the second state, the indoor space 14 and the outdoor space 16 are communicated, and the blower 22 is caused to blow air from the underfloor space 15 to the indoor space 14. In the second state, only the underfloor space 15 (the dotted pattern portion) is under negative pressure, so air flows from the indoor space 14 and the outdoor space 16 into the underfloor space 15 through the gap in the first portion including the foundation 6 and the gap in the third portion including the floor 4 and the partition wall 5. In this state, the airflow rate Q2 in the blower 22 and the pressure difference ΔP2 between the underfloor space 15 and the indoor space 14 are measured. In the second measurement, the underfloor blower 23 and the differential pressure sensor 38 are not used either.

[0040] In the third state (FIG. 5), the blower 22 is attached to the window 11, the underfloor blower 23 is attached to the window 12, and the underfloor inspection hatch 13 is opened. The exhaust side of the underfloor blower 23 and the underfloor inspection hatch 13 are connected by a duct 61. The open end E1 of the tube 51 is disposed in the indoor space 14. The open end E2 of the tube 52 and the open end E3 of the tube 53 are disposed in the outdoor space 16. The open end E4 of the tube 54 is disposed in the underfloor space 15. The blower 22 blows air from the indoor space 14 to the outdoor space 16 based on an output signal CS1 of the control unit 30. The underfloor blower 23 blows air from the outdoor space 16 to the underfloor space 15 based on an output signal CS2 of the control unit 30.

[0041] The control unit 30 obtains the airflow rate Q3 in the blower 22 based on the output signal SS2 of the flow rate sensor 36, and obtains the pressure difference ΔP3 between the indoor space 14 and the outdoor space 16 based on the output signal SS3 of the differential pressure sensor 37. In addition, the control unit 30 obtains the pressure difference ΔP4 between the underfloor space 15 and the outdoor space 16 based on the output signal SS4 of the differential pressure sensor 38, and controls the airflow rate of the underfloor blower 23 so that the underfloor space 15 and the outdoor space 16 are at the same pressure.

[0042] In the third state, the underfloor space 15 and the outdoor space 16 are connected via the duct 61, the blower 22 blows air from the indoor space 14 to the outdoor space 16, and the underfloor blower 23 blows air from the outdoor space 16 to the underfloor space 15 via the duct 61. In the third state, only the indoor space 14 (the dotted pattern portion) is under negative pressure, so air flows from the underfloor space 15 and the outdoor space 16 into the indoor space 14 via the gap in the second portion including the ceiling 2 and the exterior wall 3 and the gap in the third portion including the floor 4 and the partition wall 5. In this state, the airflow rate Q3 of the blower 22 and the pressure difference ΔP3 between the indoor space 14 and the outdoor space 16 are measured while controlling the airflow rate of the underfloor blower 23 so that the underfloor space 15 and the outdoor space 16 are at equal pressure.

[0043] In the first to third measurements, the measurements of the airflow rate and pressure difference are repeatedly performed a predetermined number of times by switching the airflow rate of blower 22. The number of measurements is, for example, five times.

[0044] [Details of airtightness measurement method] The airtightness measurement method according to this embodiment will be described with reference to FIG. 6. The airtightness measurement method according to this embodiment is executed by using the airtightness measurement device 20. The measurer first sets the house 1 to a first state (S11). Next, the measurer uses the airtightness measurement device 20 to measure the airflow Q1 in the blower 22 and the pressure difference ΔP1 between the indoor space 14 and the outdoor space 16 in the first state (S12). Next, the measurer uses the airtightness measurement device 20 to calculate the first gap area A1 based on the airflow Q1 and the pressure difference ΔP1 (S13). The airtightness measurement device 20 has a function of measuring the airflow Q1 and the pressure difference ΔP1 and calculating the first gap area A1 (S41 and S42 in FIG. 7). The measurer executes S12 and S13 by pressing the button 41 of the airtightness measurement device 20 and calling this function.

[0045] Next, the measurer sets the house 1 to the second state (S14). Next, the measurer uses the airtightness measuring device 20 to measure the airflow rate Q2 in the blower 22 and the pressure difference ΔP2 between the underfloor space 15 and the indoor space 14 in the second state (S15). Next, the measurer uses the airtightness measuring device 20 to calculate the second gap area A2 based on the airflow rate Q2 and the pressure difference ΔP2 (S16). The airtightness measuring device 20 has a function of measuring the airflow rate Q2 and the pressure difference ΔP2 and calculating the second gap area A2 (S51 and S52 in FIG. 7). The measurer executes S15 and S16 by pressing the button 42 of the airtightness measuring device 20 and calling this function.

[0046] Next, the measurer sets the house 1 to a third state (S17). Next, the measurer uses the airtightness measuring device 20 to measure the airflow rate Q3 in the blower 22 and the pressure difference ΔP3 between the indoor space 14 and the outdoor space 16 in the third state (S18). Next, the measurer uses the airtightness measuring device 20 to calculate the third gap area A3 based on the airflow rate Q3 and the pressure difference ΔP3 (S19). The airtightness measuring device 20 has a function of measuring the airflow rate Q3 and the pressure difference ΔP3 while controlling the airflow rate of the underfloor blower 23 so that the underfloor space 15 and the outdoor space 16 are at equal pressure, and calculating the third gap area A3 (S61 and S62 in FIG. 7). The measurer executes S17 and S18 by pressing the button 43 of the airtightness measuring device 20 and calling this function.

[0047] Next, the measurer uses the airtightness measuring device 20 to calculate the total equivalent gap area B1 of the first portion, the total equivalent gap area B2 of the second portion, and the total equivalent gap area B3 of the third portion based on the first to third gap areas A1, A2, A3 (S20). The airtightness measuring device 20 has a function of calculating the total equivalent gap areas B1 to B3 of the first to third portions based on the first to third gap areas A1, A2, A3 (S71 in FIG. 7). The measurer executes S20 by pressing button 44 of the airtightness measuring device 20 to call this function.

[0048] [Operation of air tightness measuring device 20] The operation of the control unit 30 of the airtightness measuring device 20 will be described with reference to Figures 7 and 8. The processing shown in Figures 7 and 8 is performed by the CPU 31 executing a program (not shown) stored in the memory 32.

[0049] The control unit 30 determines whether or not a button on the input unit 33 has been pressed (S31). In S31, the control unit 30 determines whether or not any of the buttons 41 to 44 has been pressed. If a button has been pressed (S31: Yes), the control unit 30 proceeds to S32, and if no button has been pressed (S31: No), the control unit 30 proceeds to S31.

[0050] In the former case, the control unit 30 proceeds to a step corresponding to the type of the input instruction (S32). When the button 41 corresponding to the first measurement is pressed in S32 (S32: first measurement), the control unit 30 proceeds to S41. In this case, the control unit 30 measures the airflow Q1 in the blower 22 and the pressure difference ΔP1 between the indoor space 14 and the outdoor space 16 by executing the measurement process shown in FIG. 8(A) (S41). Next, the control unit 30 calculates the first gap area A1 based on the measured airflow Q1 and pressure difference ΔP1 (S42). Next, the control unit 30 stores the calculated first gap area A1 in the memory 32 (S43) and proceeds to S31.

[0051] When the button 42 corresponding to the second measurement is pressed in S32 (S32: second measurement), the control unit 30 proceeds to S51. In this case, the control unit 30 measures the airflow Q2 in the blower 22 and the pressure difference ΔP2 between the underfloor space 15 and the indoor space 14 by executing the measurement process shown in Fig. 8(A) (S51). Next, the control unit 30 calculates the second gap area A2 based on the measured airflow Q2 and pressure difference ΔP2 (S52). Next, the control unit 30 stores the calculated second gap area A2 in the memory 32 (S53) and proceeds to S31.

[0052] When the button 43 corresponding to the third measurement is pressed in S32 (S32: third measurement), the control unit 30 proceeds to S61. In this case, the control unit 30 measures the airflow rate Q3 of the blower 22 and the pressure difference ΔP3 between the indoor space 14 and the outdoor space 16 while controlling the airflow rate of the underfloor blower 23 by executing the control / measurement process shown in FIG. 8(B) (S61). Next, the control unit 30 calculates the third gap area A3 based on the measured airflow rate Q3 and pressure difference ΔP3 (S62). Next, the control unit 30 stores the calculated third gap area A3 in the memory 32 (S63) and proceeds to S31.

[0053] When the button 44 corresponding to evaluation is pressed in S32 (S32: evaluation), the control unit 30 proceeds to S71. In this case, the control unit 30 calculates the total equivalent gap areas B1, B2, B3 of the first to third regions based on the first to third gap areas A1, A2, A3 stored in the memory 32 (S71). Next, the control unit 30 causes the display unit 34 to display the calculated total equivalent gap areas B1, B2, B3 of the first to third regions (S72), and proceeds to S31.

[0054] [Measurement process details] In the measurement process shown in FIG. 8(A), the control unit 30 first sets the value of the variable n to 1 (S81). Next, the control unit 30 controls the airflow rate of the blower 22 (S82). In S82, the control unit 30 controls the airflow rate of the blower 22 to a rate different from that of the previous measurement. Next, the control unit 30 measures the airflow rate Q and the pressure difference ΔP in the blower 22 (S83). Next, the control unit 30 determines whether the value of the variable n is equal to a predetermined number of measurements (S84). If the value of the variable n is equal to the number of measurements (S84: Yes), the control unit 30 ends the measurement process. If the value of the variable n is not equal to the number of measurements (S84: No), the control unit 30 proceeds to S85. In the latter case, the control unit 30 adds 1 to the value of the variable n (S85) and proceeds to S51.

[0055] In this manner, in the measurement process, control unit 30 switches the airflow rate of blower 22 and repeats the process of measuring airflow rate Q and pressure difference ΔP in blower 22 a predetermined number of times.

[0056] [Details of control / measurement process] The control / measurement process shown in FIG. 8(B) is the measurement process shown in FIG. 8(A) with S91 and S92 added. After executing S81, the control unit 30 proceeds to S91. Next, the control unit 30 judges whether the state in which the pressure difference ΔP4 between the underfloor space 15 and the outdoor space 16 is less than 1 Pa has continued for 10 seconds (S91). If the control unit 30 judges Yes in S91 (S91: Yes), it proceeds to S82, and if the control unit 30 judges No in S91 (S91: No), it proceeds to S92. In the latter case, the control unit 30 increases the airflow rate of the underfloor blower 23 by 1% (S92) and proceeds to S91. After executing S85, the control unit 30 proceeds to S91.

[0057] In this way, in the control / measurement process, the control unit 30 controls the airflow rate of the under-floor blower 23 so that the pressure in the under-floor space 15 and the outdoor space 16 is equal, while switching the airflow rate of the blower 22, and repeats the process of measuring the airflow rate Q3 and pressure difference ΔP3 in the blower 22 a predetermined number of times.

[0058] [Calculation of the first to third gap areas A1 to A3] In S42, S52, and S62, the control unit 30 calculates the gap area A based on the airflow rate Q and the pressure difference ΔP by the following method. As described in Non-Patent Document 1, the following formula (1) holds between the indoor / outdoor pressure difference ΔP and the airflow rate Q. Note that formula (1) is called the airflow characteristic formula. Q = a(ΔP) 1 / n …(1) In formula (1), a is the air permeability and n is the gap characteristic value. The air permeability a is the amount of air per hour when the pressure difference between the inside and outside of the room is 1 Pa. The gap characteristic value n takes a value within the range of 1 to 2, approaching 1 when the gap is small and approaching 2 when the gap is large such as a simple opening. The unit of pressure difference ΔP is Pa, and the unit of air permeability Q is m 3 / h, coefficient a is in m 3 / (h Pa 1 / n ) and the characteristic value n is dimensionless.

[0059] From equation (1), the following equation (2) is derived. logQ=loga+(1 / n)·logΔP …(2) As shown in Fig. 9, the relationship between the pressure difference ΔP and the airflow rate Q is a straight line on a double logarithmic graph. The air permeability a and the gap characteristic value n can be calculated by performing regression analysis using the least squares method based on equation (2).

[0060] The gap area A is calculated based on the air permeability a and the gap characteristic value n using the following formula (3). A = (1 / 0.36)·a(ρ / 2) 1 / 2 (9.8) (1 / n-1 / 2) …(3) In equation (3), ρ is the density of air. The unit of the gap area A is cm 2 , the density of air ρ is in g / cm 3 The gap area A corresponds to the total equivalent gap area αA in Non-Patent Document 1.

[0061] In S42, the control unit 30 calculates the first gap area A1 by the above method using the airflow rate Q1 and the pressure difference ΔP1. In S52, the control unit 30 calculates the second gap area A2 by the above method using the airflow rate Q2 and the pressure difference ΔP2, and in S62, the control unit 30 calculates the third gap area A3 by the above method using the airflow rate Q3 and the pressure difference ΔP3.

[0062] [Calculation of total equivalent gap area B1 to B3 of the first to third parts] In S71, the control unit 30 calculates the total equivalent gap area B1 to B3 of the first to third regions based on the first to third gap areas A1 to A3 by the following method. In the first state, the indoor space 14 and the underfloor space 15 are connected to each other to form a single closed space. This closed space is partitioned by the first region (a portion including the foundation 6) and the second region (a portion including the ceiling 2 and the exterior wall 3). Therefore, the first gap area A1 calculated in S42 is equal to the sum of the total equivalent gap area B1 of the first region and the total equivalent gap area B2 of the second region. Therefore, the following formula (4a) is established. A1 = B1 + B2 … (4a)

[0063] In the second state, the underfloor space 15 becomes a closed space. This closed space is partitioned by the first portion and the third portion (a portion including the floor 4 and the partition wall 5). Therefore, the second gap area A2 calculated in S52 is equal to the sum of the total equivalent gap area B1 of the first portion and the total equivalent gap area B3 of the third portion. Therefore, the following formula (4b) is established. A2=B1+B3 …(4b)

[0064] In the third state, the indoor space 14 becomes a closed space. This closed space is partitioned by the second portion and the third portion. Therefore, the third gap area A3 calculated in S62 is equal to the sum of the total equivalent gap area B2 of the second portion and the total equivalent gap area B3 of the third portion. Therefore, the following formula (4c) is established. A3 = B2 + B3 …(4c)

[0065] In S71, the control unit 30 calculates the total equivalent gap areas B1 to B3 of the first to third regions by solving the formulas (4a) to (4c) as simultaneous linear equations with three unknowns. For example, the control unit 30 calculates the value S according to the following formula (5), and calculates the total equivalent gap areas B1 to B3 of the first to third regions according to the following formulas (6a) to (6c). S = (A1 + A2 + A3) / 2 … (5) B1=S-A3 …(6a) B2=S-A2 …(6b) B3=S-A1 …(6c) In S71, the control unit 30 performs arithmetic operations on the first to third gap areas A1 to A3 to calculate the total equivalent gap areas B1 to B3 of the first to third portions.

[0066] In the above description, the underfloor blower 23 is an example of a second blower. The duct 61 is an example of an airtight flow path. S12 and S41 are examples of a first measurement step. S13 and S42 are examples of a first calculation step. S15 and S51 are examples of a second measurement step. S16 and S52 are examples of a second calculation step. S18 and S61 are examples of a third measurement step. S19 and S62 are examples of a third calculation step. S20 and S71 are examples of a fourth calculation step. 1 Pa in S91 is an example of a predetermined amount, and 10 seconds is an example of a predetermined time. 1% in S92 is an example of a predetermined increase.

[0067] [Effects of the embodiment] As described above, the airtightness measurement method according to the embodiment of the present invention includes a first measurement step (S12 and S41) of measuring the airflow rate Q1 and the pressure difference ΔP1 in a first state, a first calculation step (S13 and S42) of calculating the first gap area A1 based on the airflow rate Q1 and the pressure difference ΔP1, a second measurement step (S15 and S51) of measuring the airflow rate Q2 and the pressure difference ΔP2 in a second state, and a second calculation step (S16 and S52) of calculating the second gap area A2 based on the airflow rate Q2 and the pressure difference ΔP2. The method includes a second calculation step (S16 and S52) of calculating a third gap area A3 based on the first to third gap areas A1 to A3, a third measurement step (S18 and S61) of measuring the air flow rate Q3 and the pressure difference ΔP3 in the third state, a third calculation step (S19 and S62) of calculating a third gap area A3 based on the air flow rate Q3 and the pressure difference ΔP3, and a fourth calculation step (S20 and S71) of calculating a total equivalent gap area A1 of the first portion including the foundation 6 of the building (house 1) based on the first to third gap areas A1 to A3.

[0068] Therefore, according to the airtightness measurement method of this embodiment, the three gap areas A1 to A3 are calculated based on the airflow Q and pressure difference ΔP measured in the three states, and the total equivalent gap area B1 of the first portion is calculated based on the three gap areas A1 to A3, so that the airtightness of the first portion can be measured. In addition, in the third state, air is blown from the indoor space 14 to the outdoor space 16, and air is blown from the outdoor space 16 to the underfloor space 15, so that the airflow Q3 and the pressure difference ΔP3 can be measured in a state where the underfloor space 15 and the outdoor space 16 are at equal pressure. Therefore, the third gap area A3 can be accurately calculated, and the total equivalent gap area B1 of the first portion can be accurately calculated. Therefore, the airtightness of the first portion of the house 1 with the foundation insulation can be accurately measured.

[0069] In the third measurement step, the airflow rate of the underfloor blower 23 (second blower) is controlled so that the underfloor space 15 and the outdoor space 16 are at equal pressure. This makes it possible to measure the airflow rate Q3 and the pressure difference ΔP3 in a state where the underfloor space 15 and the outdoor space 16 are at equal pressure. This makes it possible to accurately calculate the third gap area A3 and accurately calculate the total equivalent gap area B1 of the first portion.

[0070] Furthermore, in the third measurement step, the airflow rate of the underfloor blower 23 is increased by a predetermined increment (1%) until the pressure difference ΔP4 between the underfloor space 15 and the outdoor space 16 remains less than 1 Pa (predetermined amount) for 10 seconds (predetermined time) or more. Therefore, the airflow rate Q3 and the pressure difference ΔP3 can be measured with the underfloor space 15 and the outdoor space 16 at equal pressures. Therefore, the third gap area A3 can be accurately calculated, and the total equivalent gap area B1 of the first portion can be accurately calculated.

[0071] In the fourth calculation step, the total equivalent gap area B1 of the first portion is calculated by performing the four basic arithmetic operations on the first to third gap areas A1 to A3. Therefore, the total equivalent gap area B1 of the first portion can be easily calculated by performing the four basic arithmetic operations on the three gap areas A1 to A3.

[0072] In addition, in the fourth calculation step, the total equivalent gap area B2 of the second portion and the total equivalent gap area B3 of the third portion are further calculated based on the first to third gap areas A1 to A3. Therefore, the three gap areas A1 to A3 are calculated based on the airflow Q and pressure difference ΔP measured in the three states, and the total equivalent gap areas B2 and B3 of the second and third portions are calculated based on the three gap areas A1 to A3, so that the airtightness of the second and third portions can be measured. In addition, in the third state, air is blown from the indoor space 14 to the outdoor space 16, and air is blown from the outdoor space 16 to the underfloor space 15, so that the airflow Q3 and the pressure difference ΔP3 can be measured in a state where the underfloor space 15 and the outdoor space 16 are at equal pressure. Therefore, the third gap area A3 can be accurately calculated, and the total equivalent gap areas B2 and B3 of the second and third portions can be accurately calculated. Therefore, the airtightness of the second and third portions of the building with the foundation insulation can be accurately measured.

[0073] In the fourth calculation step, the first to third gap areas A1 to A3 are subjected to arithmetic operations to calculate the total equivalent gap areas B1 to B3 of the first to third regions. Therefore, the total equivalent gap areas B1 to B3 of each region can be easily calculated by performing arithmetic operations on the three gap areas A1 to A3.

[0074] The airtightness measurement method further includes a step (S11) of setting the building to a first state before the first measurement step, a step (S14) of setting the building to a second state before the second measurement step, and a step (S17) of setting the building to a third state before the third measurement step. Thus, the building can be set to three states, and the airflow Q and pressure difference ΔP can be measured in each state.

[0075] Since the airtightness of a house depends on the construction of the house, it is essential to measure the airtightness at the construction site. In order to improve the airtightness of a house, it is effective to determine the gap area of ​​each part of the house and repair the parts with a large gap area. In particular, in a house with high airtight specifications, the gap area of ​​the whole house is small, and the gap area of ​​each part is even smaller, so it is necessary to accurately determine the gap area of ​​each part.

[0076] In general, the pressure difference between the underfloor space and the outdoor space of a house is easily affected by disturbances such as external wind. The airtightness measurement method described in Non-Patent Document 2 does not have a means for reducing the pressure difference between the underfloor space and the outdoor space, so the pressure difference between the underfloor space and the outdoor space varies due to disturbances, and the gap area of ​​each part of the house cannot be accurately measured.

[0077] In contrast, according to the airtightness measurement method of this embodiment, in the third state, the airflow rate of the underfloor blower 23 is controlled so that the pressure in the underfloor space 15 and the outdoor space 16 is equal, thereby eliminating the influence of disturbances and accurately measuring the gap area for each part of the house 1. Therefore, based on accurate measurement results, the airtightness of the house 1 can be further improved. In addition, by automatically controlling the airflow rate of the underfloor blower 23 using the airtightness measurement device 20, the gap area for each part of the house 1 can be accurately and easily measured.

[0078] [Variations] Various modifications can be made to the airtightness measurement method according to the present embodiment. The airtightness measurement method according to the modifications may be performed using an airtightness measurement device having a configuration different from that of the airtightness measurement device 20. For example, the airtightness measurement device may include two temperature sensors outside the main device 21. The two temperature sensors are arranged in the same space as the open ends E1 and E2 of the tubes 51 and 52, respectively, and measure the temperature of each space. When the difference between the two measured temperatures is greater than or equal to a predetermined value, the control unit 30 may not execute the airtightness measurement method. Alternatively, the control unit 30 may calculate the density ρ of air by referring to the measured temperature.

[0079] In the airtightness measurement method according to the present embodiment, the control unit 30 determines in S91 whether a state in which the pressure difference ΔP4 between the underfloor space 15 and the outdoor space 16 is less than 1 Pa has continued for 10 seconds, and in S92 increases the airflow rate of the underfloor blower 23 by 1%. In the airtightness measurement method according to the modified example, the threshold value of the pressure difference ΔP4, the threshold value of the state duration, and the increase rate of the airflow rate may be values ​​other than those described above. For example, the control unit 30 may determine in S91 whether a state in which the pressure difference ΔP4 is less than 0.5 Pa has continued for 5 seconds, and in S92 increase the airflow rate of the underfloor blower 23 by 2%.

[0080] In the airtightness measurement method according to the modified example, the first to third measurements may be performed in any order. For example, in the airtightness measurement method according to the modified example, S14 to S16 may be performed first, S17 to S19 may be performed next, S11 to S13 may be performed next, and S20 may be performed last.

[0081] In the airtightness measurement method according to the modified example, the measurer may calculate the total equivalent gap area B1 to B3 of the first to third portions based on the first to third gap areas A1 to A3 without using the airtightness measurement device 20. After calculating the first to third gap areas A1 to A3 using the airtightness measurement device 20, the measurer can calculate the total equivalent gap area B1 to B3 of the first to third portions by performing a simple calculation on the calculated first to third gap areas A1 to A3.

[0082] In the airtightness measurement method according to the modified example, the measurer may measure the airflow Q and the pressure difference ΔP using the airtightness measurement device 20, and then calculate the first to third gap areas A1 to A3 without using the airtightness measurement device 20. For example, the measurer may input the measured airflow Q and pressure difference ΔP into spreadsheet software and have the spreadsheet software perform regression analysis by the least squares method to calculate the first to third gap areas A1 to A3. In this case, the measurer calculates the first to third total equivalent gap areas B1 to B3 without using the airtightness measurement device 20.

[0083] The airtightness measurement method according to the modified example may further include a step of calculating equivalent gap areas C1 to C3 of the first to third regions. The equivalent gap area C is a value obtained by dividing the total equivalent gap area A by the region area S, and is also called the C value. By calculating the equivalent gap area C of each region, the airtightness of each region can be easily evaluated.

[0084] [Appendix 1] A method for measuring airtightness of a part of a building with a basic insulation, comprising: a first measurement step of measuring an airflow rate of the blower and a pressure difference between the indoor space and the outdoor space in a first state in which an indoor space and an underfloor space of the building are communicated and a blower is caused to blow air from the indoor space to an outdoor space of the building; a first calculation step of calculating a first gap area based on the airflow rate and the pressure difference measured in the first measurement step; a second measuring step of measuring an airflow rate of the blower and a pressure difference between the underfloor space and the indoor space in a second state in which the indoor space and the outdoor space are communicated and the blower is caused to blow air from the underfloor space to the indoor space; A second calculation step of calculating a second gap area based on the airflow rate and the pressure difference measured in the second measurement step; a third measurement step of measuring an airflow rate of the blower and a pressure difference between the indoor space and the outdoor space in a third state in which the underfloor space and the outdoor space are communicated via an airtight flow path, the blower is caused to blow air from the indoor space to the outdoor space, and a second blower different from the blower is caused to blow air from the outdoor space to the underfloor space via the airtight flow path; a third calculation step of calculating a third gap area based on the airflow rate and the pressure difference measured in the third measurement step; An airtightness measurement method comprising a fourth calculation step of calculating a total equivalent gap area of ​​the first portion including the foundation of the building based on the first gap area, the second gap area, and the third gap area.

[0085] [Appendix 2] 2. The airtightness measurement method according to claim 1, wherein in the third measurement step, the airflow rate of the second fan is controlled so that the underfloor space and the outdoor space are at equal pressure.

[0086] [Appendix 3] An airtightness measurement method as described in Appendix 2, in which in the third measurement step, the airflow volume of the second blower is increased by a predetermined increment until the pressure difference between the underfloor space and the outdoor space remains less than a predetermined amount for a predetermined period of time or longer.

[0087] [Appendix 4] An airtightness measurement method as described in Appendix 1, in which the fourth calculation step calculates the total equivalent gap area of ​​the first portion by performing arithmetic operations on the first gap area, the second gap area, and the third gap area.

[0088] [Appendix 5] An airtightness measurement method as described in Appendix 1, in which the fourth calculation step further calculates a total equivalent gap area of ​​a second part including the ceiling and exterior walls of the building, and a total equivalent gap area of ​​a third part including the floor and partition walls of the building based on the first gap area, the second gap area, and the third gap area.

[0089] [Appendix 6] An airtightness measurement method as described in Appendix 5, in which the fourth calculation step calculates the total equivalent gap area of ​​the first portion, the total equivalent gap area of ​​the second portion, and the total equivalent gap area of ​​the third portion by performing arithmetic operations on the first gap area, the second gap area, and the third gap area.

[0090] [Appendix 7] setting the building in the first state prior to the first measuring step; setting the building in the second state prior to the second measuring step; An airtightness measurement method according to any one of appendices 1 to 6, further comprising a step of setting the building in the third state prior to the third measurement step. [Explanation of symbols]

[0091] 1. Housing (building) 2. Ceiling 3. Exterior wall 4. Floor 5. Partition wall 6...Fundamentals 11, 12... Windows 13... Underfloor inspection hatch 14. Indoor Space 15 Underfloor space 16. Outdoor Space 20. Air tightness measuring device 21. Main unit 22... Blower 23...Underfloor blower (second blower) 30...Control section 36...Flow sensor 37, 38... Differential pressure sensor 61...Duct (airtight passage)

Claims

1. A method for measuring airtightness of a part of a building with a basic insulation, comprising: a first measurement step of measuring an airflow rate of the blower and a pressure difference between the indoor space and the outdoor space in a first state in which an indoor space and an underfloor space of the building are communicated with each other and a blower is caused to blow air from the indoor space to an outdoor space of the building; a first calculation step of calculating a first gap area based on the airflow rate and the pressure difference measured in the first measurement step; a second measuring step of measuring an airflow rate of the blower and a pressure difference between the underfloor space and the indoor space in a second state in which the indoor space and the outdoor space are communicated and the blower is caused to blow air from the underfloor space to the indoor space; a second calculation step of calculating a second gap area based on the airflow rate and the pressure difference measured in the second measurement step; a third measurement step of measuring an airflow rate of the blower and a pressure difference between the indoor space and the outdoor space in a third state in which the underfloor space and the outdoor space are communicated via an airtight flow path, the blower is caused to blow air from the indoor space to the outdoor space, and a second blower different from the blower is caused to blow air from the outdoor space to the underfloor space via the airtight flow path; a third calculation step of calculating a third gap area based on the airflow rate and the pressure difference measured in the third measurement step; and a fourth calculation step of calculating a total equivalent gap area of ​​a first portion including a foundation of the building and not including a ceiling, an exterior wall, a floor, and a partition wall of the building based on the first gap area, the second gap area, and the third gap area; In the third measuring step, the airflow rate of the second fan is controlled so that the underfloor space and the outdoor space are at equal pressure.

2. The airtightness measurement method described in claim 1, wherein in the third measurement step, the airflow volume of the second blower is increased by a predetermined increment until the time during which the pressure difference between the underfloor space and the outdoor space is less than a predetermined amount continues for a predetermined period of time or longer.

3. The airtightness measurement method described in claim 1, wherein in the fourth calculation step, the total equivalent gap area of ​​the first portion is calculated by performing arithmetic operations on the first gap area, the second gap area, and the third gap area.

4. The airtightness measurement method described in claim 1, wherein the fourth calculation step further calculates a total equivalent gap area of ​​a second portion including the ceiling and exterior walls of the building but not including the foundation, floor, and partition walls of the building, and a total equivalent gap area of ​​a third portion including the floor and partition walls of the building but not including the foundation, ceiling, and exterior walls of the building, based on the first gap area, the second gap area, and the third gap area.

5. The airtightness measurement method described in claim 4, wherein in the fourth calculation step, the total equivalent gap area of ​​the first portion, the total equivalent gap area of ​​the second portion, and the total equivalent gap area of ​​the third portion are calculated by performing arithmetic operations on the first gap area, the second gap area, and the third gap area.

6. setting the building in the first state prior to the first measuring step; setting the building in the second state prior to the second measuring step; 6. The airtightness measurement method according to claim 1, further comprising the step of setting the building in the third state before the third measurement step.

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