JP4939842B2 - Sound insulation method for piping - Google Patents

Description

  The present invention relates to a sound insulation method for piping in which a soundproof material for piping is coated on the outer periphery of the piping in order to block sound generated in the piping of a house or a building.

  Conventionally, sound insulation such as glass wool or rock wool or a sound insulation sheet made of such a sound insulation material is wrapped around the circumference of the pipe and fixed with a wire or the like in order to cut off the sound generated in the pipe of a house or building. It has been broken. In addition, a sound insulation material for piping is proposed in which a soft sound absorbing material is laminated on the inner periphery of a sound insulation sheet that is bent into a cylindrical shape, and a split groove is provided in the longitudinal direction (Patent Document 1). However, a method of winding a soundproofing material such as glass wool or a sound insulating sheet around a pipe and fixing it with a wire or the like on the site is troublesome in construction and cannot be said to have a sufficient sound insulating effect. In addition, the formation of a sound insulating material that is bent into a cylindrical shape and has a split groove requires a special process, which increases costs, and the obtained cylindrical sound insulating material is bulky when stored and transported. In addition, there is a problem that a large amount of space is required as compared with a plate-like sound insulating material.

  In addition, a pipe soundproof material made of a tubular material formed by combining at least two layers made of a sound insulating material, a vibration insulating material, a vibration damping material, and a sound absorbing material is prepared in advance. Is made of a material that can be deformed into a flat shape, and when the pipe is inserted into the cylindrical object, an outer diameter is provided so that the cylindrical object can be brought into close contact with the outer periphery of the pipe. A construction method of a pipe soundproof structure has been developed in which the inner peripheral surface of a cylindrical object can move without being bonded to the outer periphery of the pipe when inserted (Patent Document 2). However, further improvements are required in fire resistance and sound insulation effect.

Japanese Patent Laid-Open No. 4-11130 Japanese Patent No. 3656019

SUMMARY OF THE INVENTION An object of the present invention is to provide a pipe sound insulation method that is excellent in sound insulation effect and simple in construction by using a sound insulation material for pipes composed of a sound insulation layer and a sound absorption layer.
More specifically, the present invention has the following problems to be solved.
(1) In a soundproof material for piping composed of two layers of a sound insulating layer and a sound absorbing layer, peeling of the sound insulating layer and the sound absorbing layer due to the difference between the outer diameter of the outer sound insulating layer and the inner diameter of the inner sound absorbing layer is eliminated at the time of piping construction.
(2) Use felt made of inorganic fibers such as glass wool for the sound absorbing layer to provide fire resistance.
(3) Prevent scattering of inorganic fibers such as glass wool in the sound absorbing layer during construction.
(4) The solid propagation sound transmitted from the pipe is efficiently reduced.

(1) The present invention relates to the construction of a sound insulation material for piping consisting of two layers of a sound insulation layer and a sound absorption layer, and the sound insulation material for piping is composed of a sound insulation layer having an area density of 1.5 kg / m ² or more and a synthetic material. A non-woven fabric made of fibers is bonded and fixed to a sound absorbing layer integrated with an inorganic felt by needle processing, and the straight line part of the pipe is folded into a sheet-like soundproofing material before construction on the straight line part of the pipe The ends are joined to make an elliptical shape, and when constructed, it is cylindrical and is used by inserting a pipe that constitutes a straight portion of the pipe. The straight part of the pipe is characterized in that wrinkles are generated on the pipe side of the sound absorbing layer in parallel with the pipe so that an air layer is formed by partial contact between the pipe and the soundproofing material for pipe. The sound insulation method is summarized.

( 2 ) In addition, when the present invention is constructed, an elliptical soundproofing material is processed into a cylindrical shape with respect to the straight portion of the pipe, and is then passed through, and the soundproofing material is integrated in advance with respect to the joint. The gist of the above-described sound insulation method for piping (1), in which the joint is constructed, or a soundproof material is wound around the joint later.

( 3 ) Further , according to the present invention, the above-described elliptical soundproofing material is coated with an adhesive on the surface of the sound insulation layer, and the sound absorption layer is bonded so that the polyester nonwoven fabric is located on the surface. The gist of the above-mentioned 2 sound insulation method for piping is that for folding and sound insulation layers to be pressed against each other, and by further sticking an adhesive tape thereon for hard vinyl chloride pipes.

(1) In a sound insulation material for piping consisting of two layers, a sound insulation layer and a sound absorption layer, the sound insulation layer is uniform after adding, for example, 0 to 100 parts by weight of a thermoplastic polymer and 100 to 2000 parts by weight of an inorganic filler to 100 parts by weight of asphalt. To achieve a surface density of 1.5 kg / m ² or more, and based on the surface density, the sound insulation for pipes of the present invention is not only excellent in sound insulation and sound absorption, A good heat insulation effect can be exhibited, and freezing and dew condensation of piping can be prevented. In addition, the soundproofing for pipes is superior in molding processability at the time of manufacturing the soundproofing material sheet for piping, and has a much improved performance compared to the conventional soundproofing sheet, which has a high surface density by using a fine powdered inorganic filler. A material sheet can be obtained.
(2) The sound insulation layer and the sound absorption layer are bonded and fixed. When installed on the pipe, wrinkles (distortions) are generated parallel to the pipe on the pipe side of the sound absorption layer, and the pipe and the soundproof material for the pipe are in partial contact. In the sound insulation material for piping consisting of two layers, a sound insulation layer and a sound absorption layer, the problem of peeling of the sound insulation layer and the sound absorption layer due to the difference between the outer diameter of the outer sound insulation layer and the inner diameter of the inner sound absorption layer at the time of piping construction Has been resolved.
(3) The sound absorbing layer is made of felt made of inorganic fibers such as glass wool and rock wool, and a non-woven fabric made of synthetic fibers is needle-processed on one side. Other than the above, since the inorganic fibers are not exposed on the surface, it is possible not only to prevent scattering but also to provide fire resistance by using felts made of inorganic fibers such as non-flammable glass wool and rock wool. Since the nonwoven fabric is needle processed in the sound absorbing layer, it can be inserted without scraping glass wool or rock wool when inserting the tube.
(4) The sound insulation layer and the sound absorption layer are bonded and fixed. When installed on the pipe, wrinkles (distortions) are generated on the pipe side of the sound absorption layer in parallel with the pipe. In addition, the air layer can provide an impedance difference in terms of spatial sound transmission, and effectively plays out the transmission loss value of the sound insulation layer. In addition, since the air layer is also excellent in heat insulating properties, it is possible to prevent condensation and freezing of the piping. Since the pipe and the pipe soundproofing material are only partially in contact with each other, the effect of attenuating the vibration that is the source of the solid-borne sound transmitted from the pipe is exhibited.
(5) In addition, as the shape, a sheet-like soundproof material is created in advance, bent and joined at the ends, and an elliptical shape is produced, so that the elliptical shape is processed into a circular shape at the time of construction. Because the non-woven fabric made of synthetic fibers integrated with inorganic felt such as glass wool and rock wool, the pipe and sound absorbing layer are slippery and easy to insert. In addition, since the difference between the outer diameter of the pipe and the inner diameter when the sound absorbing layer of the soundproofing material for pipe is made circular is 10 mm or more, the construction is simple, and it is easy to store and transport without being bulky.

  In the soundproofing material of the present invention, the sound insulating layer and the sound absorbing layer are bonded and fixed. It consists of a straight pipe member and a joint member. Basically, the straight portion is a cylindrical thing (straight pipe member) that is inserted and used. As for the joint, there is a joint member integrated in advance or a joint member wound around the joint later.

  As shown in FIGS. 1 to 3, the soundproofing material of the present invention is laminated in the order of a sound insulating layer and a sound absorbing layer, and the sound absorbing layer has a synthetic fiber integrated with an inorganic felt by needle processing on its surface. In the construction, inorganic fibers are prevented from scattering. The sound absorbing layer mainly composed of inorganic fibers is connected to the pipe using a joint member for the joint, and the straight part is connected to the pipe using a straight pipe member so that an air layer is formed by contacting the pipe. The outer periphery of the cover is covered with no gap and fixed with an adhesive tape, a band, a wire or the like.

  The shape of the straight pipe member is cylindrical, and a sheet-like soundproof material is prepared in advance, bent and joined at the ends to produce an elliptical shape shown in FIG. At the time of construction, it is cylindrical and is inserted into a straight pipe (hereinafter, the pipe may be referred to as a “PVC pipe”). That is, at the time of construction, an elliptical object is processed into a circular shape, and a pipe is passed therethrough. Since the synthetic fiber integrated with the inorganic felt by needle processing is in contact with the pipe when the pipe is inserted, the pipe and the sound absorbing layer are slippery and easy to insert. Since the nonwoven fabric is needle processed in the sound absorbing layer, the outer diameter of the pipe that can be inserted without scraping glass wool or rock wool when inserting the pipe, and the inner diameter when the sound absorbing layer of the sound insulating material for the pipe is made circular It is desirable that the difference of 10 mm or more.

The sound generated from the supply pipe is an air sound that is a sound of a water flow flowing through the pipe and a solid sound that is generated by vibrating the pipe when the water flow hits the pipe. The soundproofing material of the present invention comprises a soundproofing layer and a sound absorbing layer that are bonded and fixed, absorbs aerial sound with a sound absorbing material (sound absorbing layer) on the tube side, and further has a high specific gravity damping soundproofing material (sound insulating layer) on the outside. ) Reflects air sound, absorbs solid sound, and attenuates sound transmitted outside.
In the soundproofing material of the present invention, the soundproofing layer and the sound absorbing layer are bonded and fixed, and when installed on a straight pipe, wrinkles (distortions) are generated in parallel with the pipe on the pipe side of the sound absorbing layer. Partially touch. Therefore, the sound insulation layer and the sound absorption layer are not peeled off, and the straight pipe and the sound insulation material for the pipe are in partial contact, so that the air layer can provide an impedance difference in terms of spatial sound transmission, and the sound insulation layer can be transmitted. It plays the role of drawing out the loss value effectively.
The sound is absorbed and attenuated by the fact that air gaps are formed by pores existing in the layers mainly composed of wrinkles and inorganic fibers generated on the pipe side of the sound absorbing layer in parallel with the pipes. When sound waves are incident on the air, the air contained in the gaps between the thin fibers vibrates, and part of the sound energy is converted into heat energy by viscous friction with the fiber surface.
The sound insulation layer has a surface density of 1.5 kg / m ² or more. When sound passes through an object, the sound is attenuated by the mass law that sound transmission decreases as the density of the object increases.

  In this way, the air layer formed by the partial contact between the pipe and the soundproofing material for the pipe can provide an impedance difference in terms of spatial sound transmission, and serves to effectively extract the transmission loss value of the sound insulating layer. In addition, since the air layer is also excellent in heat insulating properties, it is possible to prevent condensation and freezing of the piping. Since the pipe and the pipe soundproofing material are only partially in contact with each other, the effect of attenuating the vibration that is the source of the solid-borne sound transmitted from the pipe is exhibited.

As for the sound insulation layer constituting the sound insulation material for piping, the sound insulation layer of the present invention may have a surface density of 1.5 kg / m ² or more, for example, a thermoplastic resin such as polyvinyl chloride or polypropylene, There is an asphalt mixed with an inorganic filler to form a sheet. About this sound insulation layer, you may add intensity | strength to the front and back of this sheet-like thing, and you may laminate | stack sheets, such as a nonwoven fabric, a woven fabric, paper, and a film, for a design. The thickness of the sound insulation layer is 5 mm or less, preferably 2.5 mm or less from the viewpoint of workability.

More specifically, the sound insulation layer of the present invention is obtained by uniformly mixing after adding 0 to 100 parts by weight of a thermoplastic polymer and 100 to 2000 parts by weight of an inorganic filler to 100 parts by weight of asphalt. Use 1.5 kg / m ² or more. When a thermoplastic polymer is added, an inorganic filler may be added to a premixed asphalt and polymer. There is no restriction | limiting in particular as asphalt to be used, What is generally called asphalt, for example, natural asphalt, and petroleum asphalts, such as straight asphalt and blown asphalt, are used. These asphalts can be used alone or as a mixture of two or more.

  Thermoplastic polymers include polyolefin, polyvinyl chloride, nylon, ethylene / vinyl acetate copolymer, ethylene / acrylic acid copolymer, ethylene / methyl acrylate copolymer, ethylene / ethyl acrylate copolymer, styrene / A butadiene copolymer, natural rubber, natural rosin, modified rosin and the like can be used, and it is particularly preferable to use a styrene / butadiene block copolymer.

  Inorganic fillers include iron, copper, lead, tin, zinc, nickel, stainless steel and other metal powders, iron oxide, iron sesquioxide, iron tetroxide, ferrite, lead oxide, tin oxide, zinc oxide, and oxidation. Metal oxides such as copper and aluminum oxide, metal salts such as barium sulfate, calcium sulfate, lead sulfate, aluminum sulfate, calcium sulfite, calcium carbonate, lead carbonate, barium carbonate, magnesium hydroxide, steelmaking slag, mica, clay, talc Zinc flower, wollastonite, diatomaceous earth, silica sand, pumice powder and the like can be used, and these can be used alone or in admixture of two or more.

  Preferred inorganic fillers include iron powder, various iron oxide powders, steelmaking slag powder, calcium carbonate, calcium bicarbonate, etc., and these should be used as powders having a particle size of 0.5 mm or less, particularly 0.2 mm or less. Is particularly preferred. By using such finely pulverized inorganic filler, molding processability when producing a sound insulation sheet for piping is improved, and a large amount of inorganic filler is uniformly dispersed and blended in the asphalt base material. Thus, the surface density of the sound insulation layer can be increased, and the thermal stability of the sound insulation layer can be greatly improved.

The surface density of the sound insulation layer has a close relationship with the vibration damping and sound insulation effect of the sound insulation sheet for piping, and the larger the surface density, the better the vibration damping and sound insulation effect, but the inorganic filler is added to the asphalt base material. It is extremely difficult to blend in a large amount, and it has not been possible to obtain a vibration damping and sound insulation sheet layer using a conventional asphalt base material having a high surface density.
In the present invention, by using the fine powdery inorganic filler, the surface density is 1.5 kg / m ² or more, preferably the surface density is 2.0 kg / m ² or more, more preferably 2.5 kg / m. ² or more, more preferably it is possible to obtain ones 2.8 kg / m ² or more is obtained by realizing the sound insulation layer having an excellent vibration damping sound insulation effect.

  The inorganic filler is added in an amount of 100 to 2000 parts by weight based on 100 parts by weight of asphalt. However, when the amount of the inorganic filler is less than 100 parts by weight, sufficient vibration damping and sound insulation effects cannot be obtained. When it exceeds 2000 parts by weight, the whole becomes brittle, and the workability as a sound insulation sheet for piping is lowered. In the present invention, in order to form the sound insulation layer, for example, a thermoplastic polymer and an inorganic filler are added to asphalt, and the sheet is formed after uniform mixing while heating. This is laminated with a fiber sheet, or a sound insulation layer is formed directly between fiber sheet layers by an asphalt mixture in a heated and melted state. At this time, an adhesive layer may be provided between the respective layers as necessary.

  A sheet in which an inorganic filler is added to asphalt becomes brittle as the amount of inorganic filler added increases, and the molding processability and workability become extremely poor.In the present invention, the sheet as the sound insulation layer is a fiber sheet. By sandwiching them in between, it became possible to remarkably improve the molding processability and workability of the sound insulation sheet for piping. As the fiber sheet layer constituting the sheet as the sound insulation layer of the present invention, various materials such as nonwoven fabric, felt, woven fabric, paper, paperboard and the like can be used, but nonwoven fabric or felt is used in terms of vibration damping and sound insulation effects. It is preferable. Particularly preferred examples include nonwoven fabrics made of synthetic fibers such as polyester, asphalt felt obtained by impregnating high-mass special paper with asphalt, kraft paper, and the like.

Next, the sound absorbing layer constituting the soundproof material for piping will be described.
The sound-absorbing layer that constitutes the sound-insulating material for piping is a felt made of inorganic fibers such as glass wool and rock wool, which prevents inorganic fibers from being scattered during construction. Specifically, a nonwoven fabric made of synthetic fibers is used on one side. Since the non-woven fabric made of a synthetic fiber is located on the pipe side, the inorganic fiber does not come out on the surface except for the cut surface, which prevents scattering. Moreover, the felt which consists of inorganic fibers, such as non-flammable glass wool and rock wool, is used. Examples thereof include a felt formed by treating inorganic fibers made of glass wool or rock wool with a resin binder and needle processing or the like, and a surface of the felt covered with a nonwoven fabric. Among these, felts and felt laminated materials formed from long glass fibers are particularly preferable because they are excellent in vibration damping and sound insulation performance, moldability, and workability. Since the nonwoven fabric is needle processed in the sound absorbing layer, it can be inserted without scraping glass wool or rock wool when inserting the tube.
The types of sound absorbing materials for straight pipes and joints can be different. In particular, when the soundproof material is integrally formed with the joint in advance, it is desirable to employ a rock wool felt having a high compressive strength because it is compressed using an automated press machine. Since straight pipes do not require compression treatment, glass wool having a higher sound absorption rate can be used. Even when the joint winds the soundproofing material later, glass wool having a higher sound absorption rate can be used because no compression treatment is required.
In addition, since the air layer is also excellent in heat insulating properties, it is possible to prevent condensation and freezing of the piping. Moreover, since an inorganic fiber sheet layer has moderate intensity | strength, it can stack | save a sound insulation sheet and can store and convey. Since the soundproofing material of the present invention can be easily manufactured using an inexpensive material, the manufacturing cost is low, and it can be easily cut and processed with a cutter knife or the like. Easy to install.

  Regarding the construction of soundproofing materials for piping, basically, a straight object is inserted into the cylindrical part. First, a rigid vinyl chloride pipe (hereinafter, sometimes referred to as “VU pipe”) is cut to a prescribed size. The straight pipe member is cut to a length obtained by subtracting the joint insertion allowance (for two places) from the size of the cut VU pipe. The joint insertion allowance is 50 mm, 80 mm, and 100 mm in two places for 50 mm, 75 mm, and 100 mm diameter VU pipes, respectively. Straighten the straight pipe member by hand and insert the VU pipe. When there is 1 m or more, straight pipe members are joined together and a joint tape is applied to the joint part. The length of the joint tape is about 40 cm, about 55 cm, and about 70 cm for VU tubes with diameters of 50 mm, 75 mm, and 100 mm, respectively. The piping work is the same as the normal piping work. Apply the PVC pipe adhesive to the joint insertion allowance on the outer surface of the VU pipe and the joint member receptacle, and insert the VU pipe to the stopper of the joint receptacle. When constructing a joint in which a soundproofing material is integrated in advance as a joint, a joint tape is applied to the straight pipe member and the joint member. When the soundproofing material is wound around the joint later, wrap the tape or soundproofing material so that there is no sound leakage. After piping, secure with support brackets. Use the same size fireproof double-layer pipe as the support bracket. Confirm that there are no gaps between the soundproofing materials and that you have not forgotten to apply the joint tape.

  Details of the present invention will be described in the examples. The present invention is not limited to these examples.

[Sound insulation layer] Polyester non-woven fabric in which 30 parts by weight of modified asphalt mixed with styrene / butadiene block copolymer in a ratio of 9: 1 and 70 parts by weight of calcium carbonate powder are mixed with straight asphalt, and both sides have a basis weight of 30 g / m ² The sound insulation layer was sandwiched between. Since the thickness was 2.5 mm and the specific gravity was 1.8, the surface density was 4.5 kg / m ² .
[Sound-absorbing layer] As a sound-absorbing layer, a non-woven polyester fabric having a basis weight of 30 g / m ² was needle processed into a non-woven glass fabric having a basis weight of 340 g / m ² , and a 5 mm thick layer was used.
[Soundproof material: product of the present invention] As an example of the present invention, a water-based acrylic adhesive is applied to the surface of a sound insulation layer having a width of 440 mm and a length of 1000 mm, and a sound absorption layer having a width of 420 mm and a length of 1000 mm is bonded. It was. In addition, about the sound absorption layer, it bonded together so that the polyester nonwoven fabric might be located in the surface. Thereafter, the sound-absorbing layer was folded so that the sound-absorbing layer was abutted, the sound-insulating layer was stacked 20 mm, and an acrylic adhesive tape was further applied thereon to obtain a product of the present invention for a rigid polyvinyl chloride tube having a nominal diameter of 100.
[Comparative Example] As a comparative example, a water-based acrylic adhesive was applied to the surface of a sound insulating layer having a width of 420 mm and a length of 1000 mm, and a sound absorbing layer having a width of 400 mm and a length of 1000 mm was bonded. In addition, about the sound absorption layer, it bonded together so that the polyester nonwoven fabric might be located in the surface. Thereafter, the sound absorbing layer was folded so that the sound absorbing layer was abutted, the sound insulating layer was stacked 20 mm, and an acrylic adhesive tape was further applied thereon to obtain a comparative example for a rigid polyvinyl chloride pipe having a nominal diameter of 100.

(Soundproof material insertion test)
About the above-mentioned product of the present invention and the comparative example, it was bent into a cylindrical shape by hand and inserted into a hard polyvinyl chloride tube having a nominal diameter of 100. The product of the present invention could be easily inserted. Insertion was difficult due to interference between the wrinkles and the end of the hard vinyl chloride tube. As the state after insertion, the product of the present invention is in partial contact with the hard vinyl chloride tube and the wrinkled portion of the sound absorbing layer, and in the comparative example, the wrinkle of the sound absorbing layer is crushed, and the hard vinyl chloride tube is in contact with the entire surface. It was in a state. The inner diameter of the sound absorbing layer of the present invention is 129 mm, the inner diameter of the sound absorbing layer of the comparative example is 122 mm, and the outer diameter of the vinyl chloride tube is 114 mm. The difference between the inner diameter of the sound absorbing layer of the present invention and the outer diameter of vinyl chloride is 15 mm. The difference between the inner diameter of the sound absorbing layer of the comparative example and the outer diameter of vinyl chloride was 8 mm.

(Soundproof test of soundproof material)
The experimental diagram is shown in FIG. Drainage of 18 liters of water by passing a 1.7 m long vinyl chloride pipe with a nominal diameter of 100 m through the experimental building of a wooden frame construction method that is soundproofed, and constructing the product of the present invention and a comparative example. The maximum value of noise was measured. As a result, when the product of the present invention was compared with a comparative example, it was found that the product of the present invention was superior in soundproofing performance. Further, when no soundproofing treatment was measured, a soundproofing effect was also confirmed. Table 1 shows the measurement results of drainage noise.

(Soundproof material fire resistance test)
Regarding the fire resistance performance, the test body is shown in FIG. 5 in accordance with ISO834. The heating time was 1 hour, and the determination was “Pass” when “no fuming, no harmful deformation”. As a result, the test body on which the product of the present invention was applied was acceptable and fire resistance could be confirmed.

It is a schematic cross section showing an example of the soundproof material sheet for piping of the present invention. It is a schematic cross section showing the state which wound the soundproof material for piping of this invention around piping. Explain that the soundproofing material for piping is an elliptical shape with respect to the straight portion of the piping, in which the shape before being applied to the straight portion of the piping is made by bending the sheet-like soundproofing material and joining the ends. It is a schematic cross section. It is an experiment figure of the soundproof test of the soundproofing material for piping of this invention. It is drawing which shows the test body of the fireproof test of the soundproof material for piping of this invention.

Claims (3)

In the construction of piping sound insulation material consisting of two layers, a sound insulation layer and a sound absorption layer, the sound insulation material for piping is needle processed from a sound insulation layer with a surface density of 1.5 kg / m ² or more and a nonwoven fabric made of synthetic fibers The sound absorption layer integrated with the inorganic felt is adhered and fixed.For the straight part of the pipe, the shape before construction on the straight part of the pipe is folded into a sheet-like soundproof material and the ends are joined to make an ellipse. When it is constructed, it has a cylindrical shape and is used by inserting a pipe constituting the straight part of the pipe. When the pipe is constructed, the straight part of the pipe is a sound absorbing layer. A piping sound insulation method, wherein wrinkles are generated on the piping side of the pipe in parallel with the piping so that the piping and the soundproofing material for piping are in partial contact with each other to form an air layer.   When constructing, for the straight part of the piping, elliptical soundproofing material is processed into a cylindrical shape and then passed through it, and for the joint, a joint with soundproofing material integrated in advance or after The pipe sound insulation method according to claim 1, wherein the sound insulation material is wound around the joint.   The above-mentioned elliptical soundproofing material is coated with an adhesive on the surface of the sound insulation layer, and the sound absorption layer is bonded so that the polyester nonwoven fabric is located on the surface, and then folded so that the sound absorption layer is in contact with the sound insulation layer. 3. The pipe sound insulation method according to claim 2, wherein a part of the pipe is further overlapped, and an adhesive tape is further adhered thereon for use in a hard polyvinyl chloride pipe.