JP2015055070A - Drainage system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a drainage system capable of widely securing an indoor space, while restraining influence exerted on an appearance of a building.SOLUTION: A drainage system 10 includes a drain pipe such as a fixture drain pipe 12, a horizontal drain pipe 14 and a vertical drain pipe 16, and guides drain water from a drain apparatus 102 such as a toilet installed on the second floor or the third floor to an outdoor drain pipe conduit. A branch port 24a is formed in an underfloor pipe part of the drain pipes 12, 14 and 16, and a vent pipe 18 is connected to this branch port 24a. The vent pipe 18 extends up to the outdoor side of an outer wall 118 of the building 100 by passing through an underfloor space 106, and is opened outdoors, and the vent pipe 18 is provided with a vertical pipe part 34 or a check part such as a vent valve having the check function for preventing jumping-out of the drain water from a tip opening part.

Description

  The present invention relates to a drainage system, and more particularly to a drainage system for guiding drainage from drainage devices installed on the second or third floor of a building to the outside.

  Conventionally, in a low-rise building such as a two-story or a three-story building, as a drainage system that guides drainage from a drainage device such as a toilet installed on the second or third floor to an outdoor drainage pipe, FIG. In general, drainage systems 1 and 2 as shown in FIG.

  In the drainage system 1 shown in FIG. 6, the drainage pipe 3 connected to the downstream side of the drainage trap provided in the drainage equipment, connected to the downstream side of the drainage pipe 3, and extends to the outside through the lower floor space on the upper floor. A drainage horizontal pipe 4 and a drainage stack 5 connected to the downstream side of the drainage horizontal pipe 4 and extending downward along the outer wall are provided. The upstream end of the drainage stack 5 is provided with an elongated vent pipe 6 for taking air into the pipe to prevent breakage of the drain trap when a negative pressure is generated in the pipe. . In addition, a vent cap for preventing foreign substances from entering or a vent valve (intake valve) for preventing odor leakage is provided at the distal end opening of the elongated vent pipe 6. However, in the wall drainage type drainage system 1 as shown in FIG. 6, the drainage standpipe 5 and the extended vent pipe 6 are greatly exposed to the outdoors, and there is a problem that the appearance of the building is deteriorated.

  Therefore, in recent years, as shown in FIG. 7, an indoor piping type drainage system 2 in which a pipe space (PS, also referred to as a pipe shaft) 7 is provided indoors and a drain pipe is provided therein has become the mainstream. Specifically, in the drainage system 2 shown in FIG. 7, the drainage stack 5 and the elongated ventilation pipe 6 are piped in the pipe space 7. Since the elongated vent pipe 6 opens indoors, the elongated vent pipe 6 needs a vent valve 8 for preventing odor leakage.

  However, in the conventional indoor piping type drainage system 2 as shown in FIG. 7, since the pipe space 7 for installing the extended vent pipe 6 and the vent valve 8 is provided indoors, the indoor space is limited. There is a problem. In addition, an inspection port for inspecting and maintaining the ventilation valve 8 is also required.

  Therefore, the main object of the present invention is to provide a novel drainage system.

  Another object of the present invention is to provide a drainage system capable of taking a wide indoor space while suppressing the influence on the exterior of a building.

  A first invention is a drainage system for guiding drainage from drainage devices installed on the second or third floor of a building to the outside, and is connected to a downstream side of a drain trap provided in the drainage device. Drainage pipe, drainage pipe connected to the downstream side of the equipment drainage pipe and extending to the vicinity of the pipe space provided on the floor below the installation floor of the drainage equipment. A branch port, branch formed in a pipe section that passes through the underfloor space of either a drainage standpipe connected to the downstream side of the horizontal pipe and extending downward through the pipe space, an instrument drainage pipe, a drainage horizontal pipe, or a drainage standpipe A vent pipe connected to the mouth and extending to the outdoor side of the outer wall of the building through the underfloor space and open to the outdoors, and a check provided on the vent pipe to prevent drainage from jumping out from the opening at the tip of the vent pipe Part with It is a system.

  In the first invention, the drainage system includes drainage pipes such as appliance drainage pipes, drainage horizontal pipes and drainage standing pipes, and discharges drainage from drainage equipment such as toilets installed on the second or third floor to the outdoor drainage pipes. Lead to the road. The appliance drainage pipe is connected to the downstream side of the drainage trap provided in the drainage appliance and extends to the underfloor space of the floor where the drainage appliance is installed, and the horizontal drainage pipe is connected to the downstream side of the appliance drainage pipe to It extends to the vicinity of the pipe space provided downstairs. In addition, the drainage standpipe is connected to the downstream side of the drainage horizontal pipe and extends downward through the pipe space, and the downstream side is connected to an outdoor residential land via a connection pipe such as a basic through pipe . Further, a branch port is formed in the lower floor piping portion of the drain pipe including the appliance drain pipe, the drain horizontal pipe and the drain standing pipe, and a vent pipe is connected to the branch port. The ventilation pipe extends through the underfloor space to the outdoor side of the outer wall of the building, and the tip opening is opened to the outdoors. In addition, the vent pipe is provided with a check portion such as a rise valve or a vent valve having a check function for preventing a reverse flow of the drainage in order to prevent the drainage from jumping out from the tip opening.

  According to the first aspect of the present invention, the small diameter vent pipe is branched from the underfloor piping portion of the drain pipe and is piped to the outdoor side of the outer wall through the underfloor space, so that the influence on the exterior of the building can be suppressed. In addition, the pipe space on the upper floor (the floor on which the drainage equipment is installed) becomes unnecessary, and the indoor space can be increased accordingly.

  A second invention is dependent on the first invention, and the vent pipe has a rising pipe portion that extends to a position higher than a sealing upper surface of the drain trap as a check portion.

  In the second invention, the vent pipe has a rising pipe portion extending to a position higher than the sealing upper surface of the drain trap (preferably a position higher by 150 mm or more), and this rising pipe section functions as a check portion. . In other words, even if wastewater enters the ventilation pipe, the drainage trap overflows before the drainage reaches the opening of the ventilation pipe, preventing the drainage from jumping out of the opening of the ventilation pipe. Is done.

  A third invention is dependent on the second invention, and the rising pipe portion of the vent pipe is piped so as to pass through the wall of the outer wall.

  In the third aspect of the invention, the rising pipe portion of the ventilation pipe is piped so as to pass through the wall of the outer wall of the building, for example, to be embedded in the heat insulating material filling layer between the pillars and the studs.

  According to the third invention, since the vent pipe is hardly exposed to the outdoors, the influence on the appearance of the building can be minimized.

  A fourth invention is dependent on the first invention, and is provided with a vent valve having a check function for preventing a backflow of drainage as a check part.

  In the fourth aspect of the invention, the vent pipe has a check valve for preventing the backflow of drainage, that is, the intake of outside air into the vent pipe is permitted, but the discharge of odor and drainage from the inside of the vent pipe to the outside is restricted. A vent valve is provided.

  According to the fourth invention, since the vent pipe having the check function is provided in the vent pipe, it is possible to reliably prevent the drainage of the drainage from the vent pipe and the leakage of odor.

  A fifth invention is dependent on any one of the first to fourth inventions, and is a second branch port formed in a pipe portion passing through the underfloor space of any of the appliance drainage pipe, drainage horizontal pipe and drainage stack, And a second vent pipe for communicating the second branch port with the vent pipe.

  In the fifth invention, a second branch port is formed separately from the branch port in the underfloor piping portion of the drain pipe including the appliance drain pipe, the drain horizontal pipe and the drain standing pipe. In the underfloor space, the second branch port and the vent pipe communicate with each other through the second vent pipe.

  According to the fifth aspect of the invention, since the ventilation performance is improved, the drainage can flow more smoothly, and the drainage trap can be more reliably prevented.

  According to the present invention, since the small-diameter ventilation pipe is branched from the underfloor piping portion of the drain pipe and piped to the outdoor side of the outer wall through the underfloor space, the influence on the exterior of the building can be suppressed. The pipe space on the upper floor (the floor where the drainage equipment is installed) becomes unnecessary, and the indoor space can be increased accordingly.

  The above object, other objects, features, and advantages of the present invention will become more apparent from the following detailed description of embodiments with reference to the drawings.

It is an illustration figure which shows one Example of the drainage system of this invention. It is sectional drawing which expands and shows the underfloor piping part of the drainage system of FIG. It is an illustration figure which shows the other Example of the drainage system of this invention. It is an illustration figure which shows other Example of the drainage system of this invention. It is an illustration figure which shows other Example of the drainage system of this invention. It is an illustration figure which shows an example of the conventional wall piping type drainage system. It is an illustration figure which shows an example of the conventional indoor piping type drainage system.

  Referring to FIG. 1, a drainage system 10 according to an embodiment of the present invention is applied to a low-rise building 100 such as a two-story or a three-story building, and a toilet, a sink, Drains wastewater from washing machines, baths and other drainage equipment to the outdoor drainage pipe. In this embodiment, a case where the drainage system 10 is applied to a sewage pipe for flowing sewage from a toilet on the second floor in a two-story wooden house will be described as an example.

  As shown in FIGS. 1 and 2, the drainage system 10 includes drainage pipes such as an instrument drainage pipe 12, a drainage horizontal pipe 14 and a drainage stack 16, and a ventilation pipe 18. In the description, when it is not necessary to distinguish the appliance drain pipe 12, the drain horizontal pipe 14, and the drain stack 16, they are simply described as drain pipes 12, 14, and 16.

  The appliance drain pipe 12 is a drain pipe for transporting the drainage from the drain trap 104 provided in the toilet (drainage instrument) 102 to the drainage horizontal pipe 14, and is connected to the downstream side of the drain trap 104 and is below the floor on the second floor. It extends to a space (back of the first floor) 106. The drainage horizontal pipe 14 is a drainage pipe for conveying the drainage from the appliance drainage pipe 12 to the drainage stack 16 and is connected to the downstream side of the appliance drainage pipe 12 and passes through the underfloor space 106 on the second floor. It extends to the vicinity of the pipe space 108 on the floor. The drainage stack 16 is a drainage pipe for transporting the drainage from the drainage horizontal pipe 14 downward, and is connected to the downstream side of the drainage horizontal pipe 14 to connect the pipe space 108 and the underfloor space 110 on the first floor. It extends through to the foundation 112. The downstream side of the drainage stack 16 is connected to an outdoor housing land wall 116 via a connecting pipe such as a foundation through pipe 114 that penetrates the foundation 112. The inner diameters of these drain pipes 12, 14, 16 are, for example, 75 mm.

  The drain pipes 12, 14, and 16 are formed by appropriately connecting pipes and joints made of synthetic resin such as hard vinyl chloride, and specifically, from the upstream side, the short tubular vertical pipe 20 and the elbow shape are formed. A leg joint 22, a branch joint 24 having a lateral pipe portion 24 a and a branch port 24 b formed on the upper side wall thereof, a short tubular lateral pipe 26, an elbow-shaped top joint 28, and a long vertical pipe 30. It is formed by connecting. Here, the vertical pipe portion of the vertical pipe 20 and the leg joint 22 constitutes the instrument drain pipe 12, and the horizontal pipe portion of the leg joint 22, the horizontal pipe portion 24a of the branch joint 24, the horizontal pipe 26 and the top joint 28. The horizontal pipe part constitutes the drainage horizontal pipe 14, and the vertical pipe part of the top joint 28 and the vertical pipe 30 constitute the drainage stack 16.

  The drain pipes 12, 14, 16 keep air flowing smoothly by introducing air into the pipes when negative pressure is generated in the drain pipes 12, 14, 16. A vent pipe 18 is provided to prevent breakage. The vent pipe 18 is connected to a branch port 24b formed in a pipe portion passing through the underfloor space 106 on the second floor among the drain pipes 12, 14, and 16. In this embodiment, as described above, the branch joint 24 connected to the downstream side of the leg joint 22 has the branch port 24b, and the vent pipe 18 is connected to the branch port 24b. The formation position of the branch port 24b (the connection position of the ventilation pipe 18 with respect to the drain pipes 12, 14, 16) can be changed as appropriate as long as it is in the underfloor space 106 on the second floor. Although it can be formed on the side wall of the vertical pipe 16, the branch port 24 b is preferably formed on the upper side wall of the drainage horizontal pipe 14 so that the drainage does not easily enter the ventilation pipe 18. Moreover, it is preferable to form the branch port 24b in the piping part which passes along the position near the outer wall 118 of the building 100 so that the piping length of the ventilation pipe 18 can be shortened.

  The ventilation pipe 18 includes a horizontal pipe portion 32 and a rising pipe portion 34, and is formed by appropriately connecting a pipe made of a synthetic resin such as hard vinyl chloride, a joint, or the like. The horizontal pipe portion 32 extends into the wall of the outer wall 118 of the building 100 with a predetermined upward slope (for example, 1/200) through the underfloor space 106 on the second floor. Further, the rising pipe portion 34 is bent upward from the end of the horizontal pipe portion 32 and passes through the wall of the outer wall 118 and is higher than the sealing upper surface (overflow edge) 120 of the drain trap 104 (preferably 150 mm or more). (High position). And the edge part of the riser pipe part 34 bends in the horizontal direction, and is extended to the outdoor side of the outer wall 118, and the front-end | tip opening part of the ventilation pipe 18 is open | released outdoors. The inner diameter of the vent pipe 18 is, for example, 25 mm.

  Here, the outer wall structure of a wooden house is a general inner heat insulation wall. The indoor and outdoor sides of columns and studs (structural materials) are covered with panels, etc., and the insulation is filled between the columns and studs. It has a structure. Therefore, when the rising pipe portion 34 of the ventilation pipe 18 is piped in the wall of the outer wall 118, it is preferable to pipe the rising pipe portion 34 so as to be embedded in the heat insulating material filling layer. Further, in the outer heat insulating wall, the heat insulating material is externally attached to the side surface on the outdoor side of the columns and the inter-columns, and there are many cases where the spaces between the columns and the inter-columns are hollow. 34 may be piped. Further, in the case where the building 100 has an outer wall 118 made of reinforced concrete, piping may be performed by embedding the rising pipe portion 34 of the ventilation pipe 18 in the concrete portion. In addition, since the vent pipe 18 has a small diameter, even if it is piped in the wall of the outer wall 118, the influence on the heat insulating property of the heat insulating material and the strength of the structural material is small.

  A vent cap 36 is provided at the tip opening of the vent pipe 18. The vent cap 36 prevents foreign matter such as insects, dust and snow from entering the vent pipe 18 so that the vent function of the vent pipe 18 is not hindered. A commercially available product may be used as the vent cap 36 as appropriate.

  In such a drainage system 10, when drainage from the toilet 102 flows in the drain pipes 12, 14, and 16, air is taken into the drain pipes 12, 14, and 16 from the vent pipe 18, so that the drain pipe The negative pressure generated in 12, 14, 16 is reduced. Thereby, the flow of drainage is kept smooth, and the drainage trap 104 is prevented from being broken.

  Here, since the vent pipe 18 has the rising pipe portion 34 extending to a position higher than the sealing upper surface 120 of the drain trap 104, even if drainage enters the vent pipe 18, Since the sealing water of the drain trap 104 overflows first, the drainage of the drainage from the tip opening of the vent pipe 18 is prevented. That is, the rising pipe portion 34 of the vent pipe 18 functions as a check portion that prevents the drainage from jumping out from the front end opening of the vent pipe 18. Further, since the horizontal pipe portion 32 of the vent pipe 18 is piped at a predetermined upward slope, even if drainage or rainwater enters the vent pipe 18, the drained drainage or rainwater flows down naturally. Can be discharged into the drain pipe 18.

  Further, the small-diameter ventilation pipe 18 is branched from the underfloor piping portion of the drain pipes 12, 14, and 16, and is piped to the outdoor side of the outer wall 118 through the underfloor space 106. Is omitted, so there is no need to provide pipe space on the second floor. Further, since the rising pipe portion 34 of the ventilation pipe 18 is passed through the wall of the outer wall 118, the only part exposed to the outside is the vent cap 36 provided at the tip opening of the ventilation pipe 18. Further, since the movable part such as a vent valve (intake valve) is not provided in the vent pipe 18, maintenance management becomes unnecessary or easy, and an inspection port for maintenance management becomes unnecessary.

  Further, since the toilet 102 is usually installed on the outer wall 118, the ventilation pipe 18 can be piped by a short route to the outdoor side of the outer wall 118. When the pipe space 108 on the first floor is provided at a position away from the toilet 102, the drainage horizontal pipe 14 passing through the underfloor space 106 on the second floor extends to the pipe space 108 away from it, but the ventilation pipe 18 is preferably extended from the branch port 24a toward the nearest outer wall 118 and piped so as to reach the outer wall 118 in the shortest distance. That is, the vent pipe 18 does not necessarily extend along the drainage horizontal pipe 14, and can extend in any direction.

  According to this embodiment, the small-diameter ventilation pipe 18 is branched from the underfloor piping portion of the drain pipes 12, 14, and 16 and piped to the outdoor side of the outer wall 118 through the underfloor space 106. It is not necessary to provide pipe space on the floor where the drainage device 102 is installed. Accordingly, the indoor space on the second floor can be widened as much as the pipe space can be omitted, and the degree of freedom in designing the building 100 is increased.

  Further, since the rising pipe portion 34 of the ventilation pipe 18 is passed through the wall of the outer wall 118, the portion exposed to the outside is only the vent cap 36 provided at the front end opening of the ventilation pipe 18, and the appearance of the building 100 is improved. The effect of this can be minimized.

  Furthermore, since the movable part such as a vent valve is not provided in the vent pipe 18, maintenance management becomes unnecessary or easy, and an inspection port for performing maintenance management becomes unnecessary.

  In the above-described embodiment, the rising pipe portion 34 of the ventilation pipe 18 is passed through the wall of the outer wall 118. However, as shown in FIG. 3, the rising pipe portion 34 is connected to the outdoor side of the outer wall 118. You can also. That is, in the embodiment shown in FIG. 3, the ventilation pipe 18 includes a horizontal pipe portion 32 extending to the outdoor side of the outer wall 118 of the building 100 through the second floor underfloor space 106 with a predetermined upward slope, and the outdoor side of the outer wall 118. And a rising pipe portion 34 extending to a position higher than the sealing upper surface 120 of the drain trap 104 along the wall surface of the drain trap 104.

  In the embodiment shown in FIG. 3, similarly to the embodiment shown in FIG. 1, the small-diameter ventilation pipe 18 is branched from the underfloor piping portion of the drain pipes 12, 14, and 16, and the outer wall 118 is opened through the underfloor space 106. Since piping is provided to the outside, there is no need to provide a pipe space on the second floor, and an indoor space on the second floor can be increased. In the embodiment shown in FIG. 3, the rising pipe portion 34 of the ventilation pipe 18 is also exposed to the outside, but the ventilation pipe 18 has a small diameter and the piping length of the rising pipe portion 34 is short (for example, 50 cm). Therefore, the influence on the external appearance of the building 100 is small.

  In each of the above-described embodiments, the vent cap 36 is provided at the tip opening of the vent pipe 18, but the present invention is not limited to this. A vent valve (not shown) that permits the passage of gas only in the suction direction into the vent pipe 18 may be provided at the tip opening of the vent pipe 18. As the ventilation valve, a commercially available product such as a Dolco ventilation valve for outdoor installation may be appropriately used. As a result, odor leakage from the vent pipe 18 to the outside can be prevented.

  In the case where a vent valve is provided at the tip opening of the vent pipe 18, maintenance is required because it has a movable part. However, since the vent valve can be inspected from outside, it is not necessary to provide an inspection port or the like Absent. Further, since the rising pipe portion 34 of the vent pipe 18 functions as a check portion, the vent valve in this case is not particularly required to have a check function for preventing the backflow of drainage as in the vent valve 40 described later.

  Furthermore, in each of the above-described embodiments, the rising pipe portion 34 is formed in the ventilation pipe 18, but the rising pipe portion 34 is not necessarily formed. For example, as shown in FIG. 4, a vent valve 40 having a check function for preventing the backflow of drainage, that is, outside air into the vent pipe 18, as a check portion for preventing the drainage of the drainage from jumping out from the front end opening of the vent pipe 18. However, the vent pipe 18 may be provided with a vent valve 40 that restricts the discharge of odor and drainage from the inside of the vent pipe 18 to the outside. That is, in the embodiment shown in FIG. 4, the vent pipe 18 has a horizontal pipe portion 32 that extends to the outdoor side of the outer wall 118 of the building 100 through the underfloor space 106 on the second floor with a predetermined upward slope, and the vent pipe 18. A vent valve 40 having a check function for preventing the backflow of the drainage is provided at the front end opening. A commercially available product may be used as appropriate as the vent valve 40 having a check function for preventing the backflow of drainage.

  In the embodiment shown in FIG. 4, similarly to the embodiment shown in FIG. 1, the small-diameter ventilation pipe 18 is branched from the underfloor piping portion of the drain pipes 12, 14, 16, and the outer wall 118 is opened through the underfloor space 106. Since piping is provided to the outside, there is no need to provide a pipe space on the second floor, and an indoor space on the second floor can be increased. Moreover, since the part exposed to the outdoors is only the ventilation valve 40 provided in the front-end | tip opening part of the ventilation pipe 18, the influence which acts on the external appearance of the building 100 can be suppressed to the minimum. Furthermore, odor leakage from the vent pipe 18 to the outside can be prevented. In the embodiment shown in FIG. 4, since the ventilation valve 40 having a movable part is provided, maintenance is required. However, since the ventilation valve 40 can be inspected from the outside, an inspection port or the like is not particularly required.

  Furthermore, in the above-described embodiment, only one branch port 24a is provided in the underfloor pipe portion of the drain pipes 12, 14, and 16. However, the present invention is not limited to this, and the under-floor pipe of the drain pipes 12, 14, and 16 is provided. A plurality of branch openings may be formed in the portion, and the ventilation pipes connected to the respective branch openings may be joined together in the underfloor space 106 and opened on the outdoor side of the outer wall 118. For example, as shown in FIG. 5, apart from the branch port 24 a formed in the branch joint 24, a second branch port 42 is formed in the upper portion of the side wall portion of the horizontal pipe portion of the top joint 28, and The two branch ports 42 and the horizontal pipe portion 32 of the vent pipe 18 may be communicated with each other by the second vent pipe 44. As a result, air is introduced from two places into the drain pipes 12, 14 and 16 during drainage.

  According to the embodiment shown in FIG. 5, since the ventilation performance is improved, the drainage can flow more smoothly, and the drainage trap 104 can be more reliably prevented from being broken.

  Further, in each of the above-described embodiments, the drainage system 10 is applied to the sewage pipe through which the sewage from the toilet on the second floor flows. However, the present invention is not limited to this. The drainage system 10 can also be applied to miscellaneous drainage pipes that allow miscellaneous drainage from sinks, washing machines, baths, and the like to flow. Further, the present invention can be applied to a drainage pipe of a confluence system in which a sewage pipe and a miscellaneous drainage pipe join together and drain. For example, miscellaneous drainage pipes may join the drainage system 10 for flowing sewage from the toilet 102 described above.

  Further, even in a building 100 having four or more floors, the drainage system 10 can be applied as long as the drainage pipe allows the drainage from the drainage device 102 installed on the second or third floor.

  Further, the specific numerical values such as the dimensions mentioned above are merely examples, and can be appropriately changed according to the needs of the product specifications and the like.

DESCRIPTION OF SYMBOLS 10 ... Drainage system 12 ... Drainage pipe 14 ... Drainage horizontal pipe 16 ... Drainage standpipe 18 ... Vent pipe 24a ... Branch port 34 ... Rise pipe part (return part) of vent pipe
36 ... Vent cap 40 ... Ventilation valve (check part)
42 ... 2nd branch port 44 ... 2nd ventilation pipe 102 ... Toilet (drainage device)
106 ... 2nd floor space 108 ... 1st floor pipe space 118 ... Exterior wall

Claims (5)

A drainage system for guiding drainage from drainage equipment installed on the second or third floor of a building to the outside,
A drainage pipe connected to the downstream side of a drainage trap provided in the drainage equipment and extending to a space below the floor of the floor where the drainage equipment is installed;
A drainage horizontal pipe connected to the downstream side of the appliance drainage pipe and extending through the underfloor space to the vicinity of a pipe space provided on a floor below the installation floor of the drainage appliance,
A drainage stack connected to the downstream side of the drainage horizontal pipe and extending downward through the pipe space;
A branch port formed in a pipe portion passing through the underfloor space of any of the appliance drainage pipe, the drainage horizontal pipe and the drainage stack,
A vent pipe connected to the branch port, extending to the outdoor side of the outer wall of the building through the underfloor space and opened to the outdoors, and provided in the vent pipe, and drainage from a tip opening of the vent pipe Drainage system equipped with a check part to prevent popping out.   The drainage system according to claim 1, wherein the vent pipe has a rising pipe portion that extends to a position higher than a sealing upper surface of the drain trap as the check portion.   The drainage system according to claim 2, wherein the rising pipe portion of the vent pipe is piped so as to pass through the wall of the outer wall.   The drainage system according to claim 1, wherein the vent pipe is provided with a vent valve having a check function for preventing a backflow of drainage as the check portion. A second branch port formed in a pipe portion passing through the underfloor space of any one of the appliance drain pipe, the drain horizontal pipe, and the drain standing pipe; and a second passage that communicates the second branch port with the vent pipe. The drainage system according to any one of claims 1 to 4, further comprising a trachea.

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