US3731448A

US3731448A - Duct terminator

Info

Publication number: US3731448A
Application number: US00204426A
Authority: US
Inventors: H Leo
Original assignee: Formex Manufacturing Inc
Current assignee: Formex Manufacturing Inc
Priority date: 1971-12-03
Filing date: 1971-12-03
Publication date: 1973-05-08
Anticipated expiration: 1990-05-08
Also published as: FR2161902A1; CA948571A; BE788705A; DE7238936U; DE2251986C2; DE2251986A1; FR2161902B1

Abstract

A duct terminator for use in the concrete wall of an underground vault, or the like, for housing electrical equipment, such terminator including a pair of barrier walls spaced apart at a distance substantially corresponding to the thickness of the concrete wall. A plurality of spaced receptacles extend between the barrier walls to form through passages for receipt of the extremities of a plurality of respective ducts whereby the terminator may be positioned in the concrete form for the vault wall and concrete poured thereinto to provide a plurality of spaced passages in the vault wall for receipt of the extremities of such ducts. The terminator may be made in modular form and may be formed with interlocking flanges whereby a plurality of modules may be assembled for forming a composite receptacle pattern of any desired configuration.

Description

United States Patent [191 Leo DUCT TERMINATOR Herbert S. Leo, Los Angeles, Calif.

Formex Manufacturing, Inc., Santa Monica, Calif.

Dec. 3, 1971 204,426

Inventor:

Assignee:

Filed:

Appl. No.2

Related U.S. Application Data Continuation-impart of Ser. No. 853,727, Aug. 28, 1969, abandoned.

[56] References Cited UNITED STATES PATENTS 7/1939 8/1939 8/l940 l/l946 7/1954 5/1955 4/1962 8/1966 6/1967 Primary ExaminerAlfred C. Perham Attorney-Francis A. Utechltet al.

[57] ABSTRACT A duct terminator for use in the concrete wall of an underground vault, or the like, for housing electrical equipment, such terminator including a pair of barrier walls spaced apartat a distance substantially corresponding to the thickness of the concrete wall. A

plurality of spaced receptacles extend between the barrier walls to form through passages for receipt of the extremities of a plurality of respective ducts whereby the terminator may be positioned in the concrete form for the vault wall and concrete poured thereinto to provide a plurality of spaced passages in the vault wall for receipt of the extremities of such ducts. The terminator may be made in modular form and may be formed with interlocking flanges whereby a plurality of modules may be assembled for forming a composite receptacle pattern of any desired configuration.

15 Claims, 18 Drawing Figures Patented May 8, 1973 3,731,448

4 Sheets-Sheet 1 Fl 5 INVENTOR.

Heme-2T .S'. L 50 Patented May 8, 1973 4 Sheets-Sheet 2 3 FIG FIG] FIGJO FIG.

INVENTOR. HERBET .5 LEO Patentgd May 8 1973- 3,731,448

4 Sheets-Sheet 4 I INVENTOR.

flseaeer 3. L50

. eiow firrmxveys' v DUCT TERMINATOR CROSS-REFERENCE TO RELATED APPLICATION This is a continuation-in-part of my patent application Ser. No. 853,727 filed Aug. 28, 1969 and now abandoned.

BACKGROUND OF THE INVENTION 1 Field of the Invention The present invention relates generally to underground ducting for receipt of electrical cables, or the like, and more specifically to duct terminators which form passages extending through concrete walls of, for example, a vault at which the ducts terminate for receipt of the extremity of the ducts.

2. Description of the Prior Art Prior art devices for termination of communication and power cables at a concrete wall are for single ducts only and are commonly referred to as end bells or coupling end bells. These end bells generally comprise a cylindrical receptacle projecting through the concrete wall and some versions thereof include an exterior flange disposed intermediate the ends of the receptacle and projecting radially outwardly for a relatively short distance. Since the end bell for each duct is an individual unit, it is necessary for the workmen building the concrete wall in which they are used to individually position each end bell to provide the desired duct spacing and to attach them individually to the form for the concrete wall or other supporting structure. Further, curing and consequent shrinkage of the concrete frequently causes it to shrink away from the exterior of the end bells thereby forming a peripheral crack through which water may pass to the interior side of the concrete wall.

SUMMARY OF THE INVENTION The present invention is characterized by a duct terminator including a pair of spaced apart barrier walls having a plurality of I receptacles extending therebetween and disposed in spaced relation with respect to one another. The receptacles form respective through passages for receiptof the extremities of ducts terminating at such wall. Thus, the terminator may be positioned within the form utilized for shaping the concrete wall and concrete may be poured between the two barrier'walls and around the receptacles to thereby provide a continuous concrete wall having passages extending therethrough for receipt of the extremity of ducts leading to such wall.

It is an object of the present invention to provide a duct terminator of the type described which locates the duct receptacles in spaced relation with respect to one another.

It is another object of the present invention to provide a duct terminator of the type described which forms a barrier to prevent water seepage through the peripheral crack formed around the receptacle by the concrete curing and shrinking away from such receptacle.

It is still another object of the present invention to provide a duct terminator of the type described which is comprised of interconnecting modules whereby the size and arrangement of the receptacles may be selected in accordance with the particular installation.

A further object of the present invention is to provide a duct terminator arrangement employing a plurality of single passage units the sides of which are formed with complementary connection means so that such units may be employed singly or in groups.

Yet a further object is to provide a removable cap for duct terminators of the aforedescribed nature.

These and other objects and the advantages of the present invention will become apparent from the consideration of the following detailed description when taken in conjunction with the accompanying drawings.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view, partially broken away, of a concrete vault including a duct terminator embodying the present invention;

FIG. 2 is a vertical sectional view, in enlarged scale, taken along the line 22 of FIG. 1;

FIG. 3 is a top view taken along the line 33 of FIG. 2;

FIG. 4 is an end elevational view of a vault including a modification of the duct terminator shown in FIG. 1;

FIG. 5 is a vertical sectional view, in enlarged scale, taken along the line 55 of FIG. 4;

FIG. 6 is an end elevational view of a vault including a second embodiment of the duct terminator of the present invention;

FIG. 7 is a vertical sectional view taken along the line 77 of FIG. 6;

FIG. 8 is a modification of the duct terminator shown in FIG. 1;

FIG. 9 is a sectional view through the center of a receptacle including in a modification of the duct terminator shown in FIG. 1;

FIG. 10 is a sectional view similar to FIG. 9 of a second modification of the duct terminator shown in FIG. 1;

FIG. 11 is a perspective view of a concrete vault utilizing a single-passage duct terminator arrangement embodying the present invention;

. FIG. 12' is a front view in enlarged scale of one of the single-passage terminators shown in FIG. 1 1;

FIG. 13 is a broken front view showing a plurality of A DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIGS. 1 and 2, generally the duct terminator 19 of the present invention is particularly adapted for use in the vertical wall of a concrete underground vault 21 for housing elect rical utility equipment (not shown) or the like. Referring to FIGS. 2 and 5, the duct terminator 19 may be molded by the vacuum process disclosed in US. Pat. No. 3,256,565

and includes a pair of

vertical side walls

27 and 29 which are spaced apart at a distance substantially equivalent to the thickness of the wall of the vault 21 in the area in which the terminator is installed and a plurality of tubular receptacles 31 extend between such walls and form through passages 33 for receipt of the extremities of ducts 35. The terminators 19 may include interfitting male and female

groove type flanges

37 and 39, respectively formed by the respective lower and upper extremities of the

walls

27 and 29 whereby such terminators may be coupled together in stacked relation as shown in FIG. 1 to provide the desired number and arrangement of receptacle passages 33. Thus, the terminators 19 may be installed in a concrete form 41 for the wall of the vault 21 and concrete may be poured thereinto. The concrete 45 will flow in and around the receptacles 31 and when such concrete cures, a continuous wall will be provided with passages 33 extending therethrough for receipt of the extremities of the ducts 35 interconnecting adjacent vaults and the

walls

27 and 29 will act as barriers against penetration of dirt or water around the outer periphery of the respective receptacles 31.

Referring to FIG. 2, the upper extremities of the

walls

27 and 29 of each of the duct terminators 19 are formed with outwardly opening horizontally extending grooves which define the female interlocking flanges 39. The lower extremities of the

walls

27 and 29 are formed with inwardly projecting horizontally extending tongues which define the male flanges 27 that interlock with the female flanges 29 of the respective adjacent terminators 19.

Referring to FIG. 5, the receptacles 31 each include a slightly frusto-conical shaped portion 47 which receives the extremities of the respective ducts 35 and reduced-in-diameter area defining a rounded shoulder 49 against which the end of the duct 35 may abut. The receptacle 31 flares radially outwardly from the shoulder 49 to define a bell shaped flare 51 over which electrical cables and/or conductors threaded through the ducts 35 may ride. i In. operation, when a vault 21 is to be poured the inner and outer forms 41 are assembled to provide a space defining the thickness of the vertical walls of such vault. The terminators 19 may then be assembled together to provide the desired number of receptacles 31 and spacing therebetween. In this regard, it is important to note that duct terminators 19' (FIG. 4) having relatively large receptacles may be assembled with the smaller terminators 19 to provide a composite terminator assembly for receipt of ducts 35 having different diameters.

After the terminators 19 are assembled and positioned within the form 4i, vertical and horizontal reinforcing

rods

61 and 63, respectively, may be installed and wired in position to provide the desired reinforcevibrated and will flow in between the adjacent receptacles 31 to provide a continuous concrete wall that extends through the space between the

vertical walls

27 and 29 of the terminators 19 through which the receptacles 31 define passages for receipt of the extremities of the ducts 35.

Subsequently the forms 41 are removed and the ducts 35 may be installed in trenches extending between adjacent vaults and the ends thereof abutted against, or positioned in confrontation with, the shoulders 49. it is noted that the slight frusto-conica] shape of the passages 33 provide for convenient insertion of the duct extremities to provide a tight fit. The extremities may be cemented in the passages 33 to provide a tight seal. Electrical cables may then be fed through ducts 35 and the lead end thereof will pass up and over the rounded shoulders 49 and such cables will ride down over the bell shaped flare 51 to be connected with equipment installedwithin the vault. It is noted that the shoulder 49 is somewhat thicker than the wall of the duct 35 whereby equal outer diameter ducts 35 having thicker walls may conveniently be installed therein. After installation of the duct 35 is complete, the trench between the ducts 35 may either be filled with concrete or soil may be thrown back into the trench and compacted. A particularly noteworthy advantage of the terminators 19 of the present invention is that the

vertical walls

27 and 29 will provide a water barrier to prevent admission of water within the cracks which are frequently formed by the curing concrete drying and shrinking and pulling away from the outer periphery of the receptacles 31.

The terminator shown in FIG. 6 is similar to that shown in FlG. 1 except that the entire pattern of receptacles forming the passages 33 are formed by a unitary terminator, generally designated 67, including single vertical outer and inner walls 69 and 71, respectively,

(FIG. 7). The trench leading-to the vault 73 shown in FIG. 7 is filled with concrete 75 which surrounds and supports the ducts 35. It will be clear from FIG. 7 that even though the curingconcrete may shrink and pull away from the outer periphery of the receptacles 31 and then out from behind the wall 69 thereby effectivement'for the concrete. It is important to note that the ly blocking entry to the vault.

The duct terminators, generally designated 81, shown in FIG. 8 are substantially similar to that shown in FIG. 1 except that one terminator is shifted longitudinally'with respect to the other to provide staggered, spaced relationship between the passages 33 whereby cables and/or conductors fed through parallel ducts connected therewith will not interfere with the cables and/or conductors fed in the same direction through the passages 33 in the adjacent terminators.

' The receptacles 31' shown in FIG. 9 are similar to those shown in FIG. 5 with the inclusion of centrally located webs, generally designated 85, which are formed by

layers

87 and 89 resulting from the forming process employed to form the receptacles 31' from the

respective walls

27 and 29. The webs are formed with peripheral weakened outlines 91 for convenient removal of such webs after the terminators have been installed. Thus, a duct terminator employing the web 85 may be installed and dirt and soil will be prevented from entering the concrete vault until such web is removed. The web 85 may then be conveniently removed immediately prior to the installation of the ducts 35. Thus, extra reserve duct terminators may be installed at the time of vault construction for future expansion and addition of more ducts 35 at a later date.

The terminators shown in FIG. are substantially similar to those shown in FIG. 1 except that the

barrier walls

27 and 29 are formed with respective top and bottom male and

female flanges

95 and 97 which interfit to maintainthe duct terminators positioned with respect to one another. Obviously, these flanges could take many different forms.

Referring now to FIGS. 11-16 there is shown a single-passage du'ct terminator, generally designated 100, embodying the present invention. With particular reference to FIG. 11, a plurality of twelve such duct terminators 100 are shown arranged in the vertical wall 102 of a concrete vault 104 to which a plurality of ducts 108 are affixed and terminated. Note that the ducts 108 are not shown in FIG. 13 in the interest of clarity. Each of the duct terminators 100 isof like construction and utilizes a pair of

vertical barrier walls

110 and 112 which are spaced apart at a distance substantially equivalent to the thickness of the wall 102 of the vault 104 in the area where the terminators are installed. An integral tubular receptacle 116 extends between the

side walls

110 and 112 to form the passage 1 14 for receipt of the extremity of one of the ducts 108.

The upper edge and left-hand edges of the

side walls

110 and 112 are formed with

male flanges

120 and 122, respectively, that complementarily interfit

female grooves

124 and 126 formed along the lower edge and right-hand edge of the other duct terminators whereby the plurality of terminators maybe coupled together in the stacked relationship shown in FIG. 11.

Again referring to FIG. 11 it will be noted that four horizontalrows of interlocked vertically spaced,,singlepassage duct terminators 100 are shown. The top row of 'duct terminators does notsupport ducts 108, but instead each terminator is provided with a cap, generally designated 130. The-details of such caps 130Iare'shownin FIGS. 16, 17 and 18. Referringv tothe latter figures, each cap 130 includes a cylindrical neck132 formed at its inner. end with a plurality of like, radially extending locking lugs 134. The opposite end .of the neck 132 is formed witha dome-shaped cover 140. The mid-portion of the cover 140 is formed with a hexagonalshaped boss 142 to receive a wrench (not shown) for a purpose to be described hereinafter. As shown at 144 in FIG. 17, the outwardly-facing surfaces, of locking lugs 134 are tapered. Y

The lockinglugs'134 of each cap are designated to enter complementary radially outwardly extending openings 146 formed in the periphery of the inner and outer ends of the passages 1 14 of the receptacles 116 of each duct terminator 100. The relative size of the locking lugs 134 and their respective openings 146 should be such that t e locking lugs can be inserted axially through the openings. Thereafter, the cap 130 will be rotated, as by the application of a wrench to the boss 142', so as to earn the tapered surfaces of the locking lugs 1,34 intotight engagement with its respective duct terminator 100. In this manner the locking lugs serve to restrain the cap 130 against inadvertent reverse rotation and provide increased sealing pressure at the interface betweenthe cap and its duct termina- Referring to FIG. 15 it should be noted that the vertical or horizontal spacing between the centers of the ducts 108 may be extended by the use of a pair of like, elongated male extenderelements 150. The upper edge of each male extender element 150 is provided with a male flange 152 which interfits with the complementary female groove 124 formed in the lower edge of each upper duct terminator 100. The lower edge of each of the male extenders 150 is formed with female grooves 156 which in turn complementarily interfit with the male flanges of the lower edge of each duct terminator 100.

To assembly the duct terminators 100 into the arrangement shown in FIG. 11, individual rows of three duct terminators 100 will be pre-assembled by means of their male and female flange and groove connections. Preferably, a suitable cement is applied to the mating surfaces. After the desired number of rows have been so pro-assembled, proximate edges of the rows will be interfitted, an adhesive again being applied to the the mating surfaces. The provision of the caps permit one or more of the duct terminators 100 to be initially sealed for later reception of a duct 108. With this arrangement the concrete vault 104 is provided with extra duct capacity when such vault is constructed and accordingly will not require costly reworking at such time as additional ducts are needed The caps 130 may be rendered watertight by utilizing a non-hardening sealant. Alternatively, if a cap is to be permanently in 16 to permit reception of a duct 108. Note that the caps130 may also be employed to'seal the inner end of the passages 1140f the duct terminators. Also, where cables and/or conductors-are not initially installed in a ductv 108 between adjacent vaults it may' be necessary to seal the-respective openings to prevent the passage, of gasses from one vault to another. The caps 130 may be utilized with the duct terminator arrangements shown in FIGS. 1-10 if openings 146 are I V provided in such duct terminators. v

From the foregoing detailed description it will be 'clear that the duct terminator of the present invention provides a practical and convenient means for'formin'g passages in the concrete walls of underground vaults for conveniently receiving the extremities of ducts extending betweenadjacent vaults. The terminators conveniently locate a pluralityof receptacles in spaced relationship and provide a-barrier to prevent the entry of dirt and water around the peripheral crack left on the outside of the receptacles whenthe concrete cures 1. Duct terminator apparatus to positioned in the I concrete wall of an underground vault or he ke at which aplurality of ducts are to terminate, said apparatus being positioned the form used to shape said wall and said apparatus comprising:

a plurality of terminator modules each including respective pairs of barrier walls spaced apart at a distance corresponding substantially to the thickness of said concrete wall and formed at their one extremities with respective female flanges and at their opposite extremities with male flanges for interfitting the female flanges of adjacent modules, each of said modules further including receptacles extending between said barrier walls to form through passages from one of said barrier walls to the other, and with said modules being assembled by interfltting the male and female flanges of adjacent modules whereby concrete poured between said vertical walls during pouring of said vault will position said modules in said vertical walls to form spaced passages for receipt of the extremities of said ducts.

2. A duct terminator apparatus as set forth in claim 1 wherein:

the intermediate portion of each of said receptacles are formed with peripheral shoulders for abutment with the extremities of the respective ducts.

3. A duct terminator apparatus as set forth in claim 1 wherein:

each of said receptacles if formed with a frustoconical shaped portion defining a passage which progressively decreases in cross-sectional area toward the wall opposite to the wall from which said ducts enter to assist in leading said ducts thereinto.

4. A duct terminator apparatus as set forth in claim ll wherein:

said receptacles are disposed in spaced-apart relationship for receiving concrete reinforcing bars therebetween.

5. A duct terminator apparatus as set forth in claim 2 wherein: 1

said receptacles are disposed in spaced-apart relationship for receiving horizontal and vertical concrete reinforcing bars therebetween.

6. A duct terminator apparatus as set forth in claim 1 wherein: n

said passages flare radially outwardly away from the wall through which said ducts enter to provide tapered surfaces over which conduits fed through said ducts may ride. 7. A duct terminator apparatus as set forth in claim 1 wherein: I

certain of said modules include receptacles formed with passages having a selected cross-section and in other of said modules the receptacles thereof are formed with passages having a second crosssection. I

8. A duct terminator apparatus as set forth in claim 1 wherein:

said female flanges are in the form of grooves and said male flanges are in the form of tongues for interlocking in said respective grooves.

9. A duct terminator apparatus as set forth in claim 8 wherein:

the grooves forming said female flanges are elongated whereby said tongues may be shifted longitudinally therein to r'e-position the receptacles of being positioned in the form used to shape said wall, and said duct terminator comprising:

a pair of barrier walls spaced apart at a distance substantially corresponding to the thickness of said concrete wall for receipt of concrete therebetween;

receptacle means extending between said barrier walls and forming through passage means from one of said barrier walls to the other of said barrier walls, the ends of said receptacle means being integral with said barrier walls whereby said terminator may be positioned in said form and concrete poured into said form to provide a concrete wall having passage means extending therethrough for receipt of the said duct; and i with the intermediate portion of said receptacle means being formed with a peripheral shoulder for abutment with the extremities of said duct, said receptacle means being provided with a radially outwardly extending flare at its end opposite the end from which said duct is received.

11. A duct terminator as set forth in claim 10 wherein:

said receptacle means includes a web normally blocking communication through said passage means and which may be removed before said duct is installed.

12. A duct terminator as set forth in claim 10:

wherein the edges of said barrier walls are formed with complementarily interfitting connection means whereby a plurality of said duct terminators may be coupled together.

13. A duct terminator as set forth in claim 10:

which further includes ,cap means removably secured to saidbarrier walls to selectively block communication through said passage means.

14. Duct terminator apparatus to be positioned in the concrete wall of an underground vault or the like at which a plurality of ducts are to terminate, said apparatus'being positioned in the form used to shape said wall and said apparatus comprising:

a plurality of like terminator modules each including respective pairs of barrier walls spaced apart at a distance corresponding substantially to the thickness of said concrete wall and formed at their edges with complementary male and female flanges and grooves for coupling said edges together, each of said modules further including a receptacle extending between said barrier walls to form a through passage from one of said barrier walls to the other, and with said modules being assembled by interfitting the male and female flanges of adjacent modules whereby concrete poured between said vertical walls during pouring of said vault will position said modules in said vertical walls to form spaced passages for receipt of the extremities of said ducts.

15. A duct terminator apparatus as set forth in claim which further includes cap means removably secured to said barrier walls to selectively block communication through said passage means.

Claims

1. Duct terminator apparatus to be positioned in the concrete wall of an underground vault or the like at which a plurality of ducts are to terminate, said apparatus being positioned in the form used to shape said wall and said apparatus comprising: a plurality of terminator modules each including respective pairs of barrier walls spaced apart at a distance corresponding substantially to the thickness of said concrete wall and formed at their one extremities with respective female flanges and at their opposite extremities with male flanges for interfitting the female flanges of adjacent modules, each of said modules further including receptacles extending between said barrier walls to form through passages from one of said barrier walls to the other, and with said modules being assembled by interfitting the male and female flanges of adjacent modules whereby concrete poured between said vertical walls during pouring of said vault will position said modules in said vertical walls to form spaced passages for receipt of the extremities of said ducts.

2. A duct terminator apparatus as set forth in claim 1 wherein: the intermediate portion of each of said receptacles are formed with peripheral shoulders for abutment with the extremities of the respective ducts.

3. A duct terminator apparatus as set forth in claim 1 wherein: each of said receptacles if formed with a frustoconical shaped portion defining a passage which progressively decreases in cross-sectional area toward the wall opposite to the wall from which said ducts enter to assist in leading said ducts thereinto.

4. A duct terminator apparatus as set forth in claim 1 wherein: said receptacles are disposed in spaced-apart relationship for receiving concrete reinforcing bars therebetween.

5. A duct terminator apparatus as set forth in claim 2 wherein: said receptacles are disposed in spaced-apart relationship for receiving horizontal and vertical concrete reinforcing bars therebetween.

6. A duct terminator apparatus as set forth in claim 1 wherein: said passages flare radially outwardly away from the wall through which said ducts enter to provide tapered surfaces over which conduits fed through said ducts may ride.

7. A duct terminator apparatus as set forth in claim 1 wherein: certain of said modules include receptacles formed with passages having a selected cross-section and in other of said modules the receptacles thereof are formed with passages having a second cross-section.

8. A duct terminator apparatus as set forth in claim 1 wherein: said female flanges are in the form of grooves and said male flanges are in the form of tongues for interlocking in said respective grooves.

9. A duct terminator apparatus as set forth in claim 8 wherein: the grooves forming said female flanges are elongated whereby said tongues may be shifted longitudinally therein to re-position the receptacles of certain modules with respect To the receptacles in other modules.

10. A duct terminator to be positioned in the concrete wall of an underground vault or the like at which the duct is to terminate, said duct terminator being positioned in the form used to shape said wall, and said duct terminator comprising: a pair of barrier walls spaced apart at a distance substantially corresponding to the thickness of said concrete wall for receipt of concrete therebetween; receptacle means extending between said barrier walls and forming through passage means from one of said barrier walls to the other of said barrier walls, the ends of said receptacle means being integral with said barrier walls whereby said terminator may be positioned in said form and concrete poured into said form to provide a concrete wall having passage means extending therethrough for receipt of the said duct; and with the intermediate portion of said receptacle means being formed with a peripheral shoulder for abutment with the extremities of said duct, said receptacle means being provided with a radially outwardly extending flare at its end opposite the end from which said duct is received.

11. A duct terminator as set forth in claim 10 wherein: said receptacle means includes a web normally blocking communication through said passage means and which may be removed before said duct is installed.

12. A duct terminator as set forth in claim 10: wherein the edges of said barrier walls are formed with complementarily interfitting connection means whereby a plurality of said duct terminators may be coupled together.

13. A duct terminator as set forth in claim 10: which further includes cap means removably secured to said barrier walls to selectively block communication through said passage means.

14. Duct terminator apparatus to be positioned in the concrete wall of an underground vault or the like at which a plurality of ducts are to terminate, said apparatus being positioned in the form used to shape said wall and said apparatus comprising: a plurality of like terminator modules each including respective pairs of barrier walls spaced apart at a distance corresponding substantially to the thickness of said concrete wall and formed at their edges with complementary male and female flanges and grooves for coupling said edges together, each of said modules further including a receptacle extending between said barrier walls to form a through passage from one of said barrier walls to the other, and with said modules being assembled by interfitting the male and female flanges of adjacent modules whereby concrete poured between said vertical walls during pouring of said vault will position said modules in said vertical walls to form spaced passages for receipt of the extremities of said ducts.

15. A duct terminator apparatus as set forth in claim 14: which further includes cap means removably secured to said barrier walls to selectively block communication through said passage means.