Multi-cable conduit for floors and walls

A multi-cable conduit has a housing which is opened at opposite ends, and a plurality of partitions dividing the interior of the housing into a plurality of compartments extending between the open ends. Each of the compartments is sized to receive a multiplicity of cables extending through the compartment and the open ends of the housing, and the compartments are elongated in a direction transverse to the axes of the cables. The partitions are slidably supported within the housing so that each partition can be separately inserted into, and removed from, the housing. A lining of intumescent material is provided on the walls of each compartment for expanding into and sealing each of the compartments in response to a fire. Compartments or portions of compartments which are not filled with cables are filled with a nonflammable insert. At least one end of each compartment is also sealed to limit the transmission of smoke through the compartments prior to expansion of the intumescent material. Directing means are also provided at the open ends of the compartments for focusing the expansion of the intumescent material into the compartments.

DESCRIPTION OF THE INVENTION 
The present invention relates generally to conduits for passing multiple 
cables, such as telephone cables, through walls and floors of buildings. 
The invention particularly relates to such conduits which include means 
for limiting the passage of heat, flame, smoke and gases through cable 
openings in walls and floors. 
When a building must be provided with holes through the floors or walls to 
provide passageways for bundles of cables, such as computer or 
communication cables or the like, fires can quickly spread through such 
holes from floor to floor or from room to room. To reduce or eliminate 
this fire hazard, such passageways are often sealed with a variety of 
different sealing means, such as a packing of mineral wool or silicone 
foam around the cables. More sophisticated sealing techniques use a heat 
expandable or intumescent material which expands and fills a conduit 
cavity in response to the elevated temperatures of a fire. Devices using 
this technique are described in U.S. Pat. Nos. 3,864,883; 3,995,102; and 
4,093,818, for example. One of the major drawbacks of these devices is 
that they are costly. More specifically, they are costly to install as 
they require a high level of skill and substantial cable installation 
time, especially for custom fitting. Then it is difficult or virtually 
impossible to inspect the integrity of the seal. Furthermore, subsequent 
additions of cables are limited to cables of a certain size and to certain 
patterns of installation. Also subsequent removal of cables is limited by 
the extensive labor involved. For these reasons as well as by inherent 
design, the prior devices make inefficient use of the cross-sectional area 
of the opening in the floor or well. Other disadvantages include lack of 
protection against smoke, such as from smoldering materials; the need to 
tailor units to specific cable sizes; and cleaning and maintenance 
problems due to various projecting and recessed structures. 
It is, therefore, a primary object of the present invention to provide an 
improved intumescent-type multi-cable conduit which not only protects 
against fires and the attendant smoke and hot gases, but also is extremely 
simple to install, requiring only a few minutes of semi-skilled labor. 
It is another important object of this invention to provide an improved 
multi-cable conduit which is capable of accommodating a wide variety of 
different types and sizes of cables in a single conduit structure without 
any custom fitting or special tailoring, and which permits the cables to 
be arranged in a completely random fashion. 
A further object of this invention is to provide such an improved conduit 
which provides a high cable density per square foot. A related object is 
to minimize the amount of space that is not available to be occupied by 
cables within the conduit and, therefore, to minimize the size of the 
opening required in a wall or floor to accommodate the conduit. 
Still another object of the invention is to provide such an improved 
multi-cable conduit which permits the cables to be easily and quickly 
inserted through the conduit, or removed therefrom, without cutting the 
cable or rearranging or even disturbing previously inserted cables. 
Yet another object of the present invention is to provide such an improved 
multi-cable conduit which can be installed virtually flush with the 
surface of the floor or wall in which it is installed, without projecting 
brackets, fasteners or other fittings. In this connection, it is also an 
objective to provide such a conduit which does not pose any cleaning or 
other maintenance problems after it is installed. 
Still another object of the present invention is to provide such an 
improved conduit which can be readily inspected, e.g., for integrity of 
the smoke seal, from the exterior without removing or disassembling the 
conduit. 
A still further object of the invention is to provide such an improved 
multi-cable conduit which limits the transmission of smoke through the 
conduit at all temperatures, even when the cable insulation or sheathing 
decomposes due to the intense heat of a fire. A corollary objective is to 
provide such a conduit that limits the transmission of smoke from 
smoldering materials and the like which do not produce temperatures high 
enough to expand an intumescent material. 
A further object of this invention is to provide such an improved 
multi-cable conduit which can be efficiently and economically manufactured 
in large numbers.

While the invention will be described in connection with certain preferred 
embodiments, it will be understood that it is not intended to limit the 
invention to these particular embodiments. On the contrary, it is intended 
to cover all alternatives, modifications and equivalent arrangements as 
may be included within the spirit and scope of the invention as defined by 
the appended claims. 
Turning now to the drawings and referring first to FIG. 1, there is shown a 
rectangular conduit 10 for passing multiple cables 11 through a concrete 
floor 12. The conduit housing 13 is inserted into a hole passing 
vertically through the floor 12 to permit the passage of the cables 11 
therethrough. The housing 13 is preferably formed of sheet metal in the 
configuration of a rectangular frame which is open at both the top and 
bottom. The conduit-receiving hole in the floor 12 is formed slightly 
larger than the housing 13, and bands 14 and 15 of intumescent material 
encircle the outside walls of the housing and are bonded thereto. These 
bands to intumescent material expand and seal off the gap between the 
housing 13 and the walls of the floor hole in the event of a fire. 
The top edge of the housing 13 forms an outwardly extending flange 13a 
which overlaps the surface of the floor 12 to support the housing. To seal 
the gap between the housing 13 and the walls of the floor hole against the 
passage of low-temperature smoke, a gasket 16 is placed beneath the flange 
13a. 
To divide the interior of the housing 13 into a plurality of compartments 
extending vertically therethrough, a plurality of partitions 20 are 
inserted therein. These partitions 20 are preferably made of sheet metal, 
and have integral side flanges 21 and 22 (see FIG. 2) along the vertical 
edges thereof so that each partition is U-shaped in horizontal section. 
The U-shaped partitions 20 slide into the housing 13 with the outer 
surfaces of the flanges 21 and 22 sliding along the interior walls of the 
housing 13, and come to rest in supporting engagement with a horizontal 
flange 23 formed around the bottom edge of the housing (see FIG. 3). The 
partitions 20 are preferably stacked loosely against each other within the 
housing 13 so that each pair of flanges 21, 22 nearly abuts the main 
partitioning wall of an adjacent partition. The two endmost partitions 20 
abut the respective end walls of the housing 13. This stacking arrangement 
forms a multiplicity of relatively narrow rectangular-shaped compartments 
24, each of which is capable of receiving cables 11 of varying sizes in 
random order. 
The bottom flange 23 on the housing section 13 is folded back on itself 
(see FIG. 3) to avoid a sharp edge that might cut the cables 11. The top 
and bottom edges of the partitions 20 are protected by folded metal or 
plastic strips 20a and 20b (see FIG. 2) for both safety and reinforcement. 
In order to seal the various rectangular compartments 24 in the event of a 
fire, and thereby prevent the fire and attendant smoke and fumes from 
spreading via the cable passageway through the floor, each of the 
compartments 24 is lined with an intumescent material. Intumescent 
materials are well known in the art and exhibit a high coefficient of 
cubic expansion under conditions of elevated temperature so that they 
expand extensively (and largely irreversibly) when subjected to heat. In 
the illustrative embodiment of FIGS. 1-9, linings 25 and 26 of intumescent 
material are affixed to opposite sides of the main wall of each partition 
20, and additional linings 27 and 28 of the same material are affixed to 
the inside surfaces of the two side flanges 21 and 22. At the one end of 
the housing where the endmost partition 20 has its flanges 21 and 22 
abutting the end wall of the housing, the housing end wall also has an 
intumescent lining on the inside surface thereof. In the event of a fire, 
the linings of intumescent material expand into tight sealing engagement 
with the cables 11 passing through the respective compartments 24. Even if 
some of the cables 11 are of small diameter, leaving substantial voids 
within the compartments 24, the intumescent material from the linings 
25-28 completely fills such voids so that the compartments are completely 
sealed off to prevent the transmission of fire and smoke therethrough. 
As is well known, the heat transfer from any fire is due to a combination 
of conduction, convection, and radiation. In a serious, major 
conflagration, the primary mode of heat transfer is via radiation. The 
effect of the narrow "slots" formed by the compartments 24 is to absorb 
most of the radiation in the intumescent linings rather than to allow it 
to be transmitted to vulnerable material on the other side of the conduit. 
In effect, the general geometry of the conduit transforms the large 
rectangular opening into a series of adjacent slots each of which 
functions in the same manner as a "peep-hole" into a furnace to protect 
the materials on the "cold" side. 
The heat expandable linings 25-28 typically comprise an intumescent 
material such as sodium silicate and/or potassium silicate in combination 
with a non-flammable filler material such as alumina, silica, mineral 
wool, glass fibers etc. Such materials are commercially available as 
prefabricated sheets which can be adhesively bonded to the desired 
surface. One example of such an intumescent sheet is FS-195 made by 3M 
Company of St. Paul, Minn. A lining of such material only 1/8 inch in 
thickness is sufficient to substantially fill a rectangular compartment 
having a cross-sectional area about one inch by six inches, and the 
pressure of the expanding material is sufficiently high that it presses 
into all the little crevices and interstices among the cables and parts of 
the conduit. At the initial blast of hot gases and/or radiation from a 
fire, these intumescent materials start to expand in response to the 
elevated temperatures, so that the rectangular compartments 24 are 
gradually filled and sealed off before the fire or attendant hot gases and 
smoke have had a chance to penetrate through the conduit. Moreover, the 
expansion starts on the fire side, squeezing the deteriorating insulation 
on the cable 11 to prevent a flue-like opening through the seal as the 
cable insulation deteriorates from the heat of the fire. The expansion 
proceeds approximately linearly as long as any empty spaces remain in the 
compartment. As will be described below, a simple cold smoke seal on the 
top side of the conduit prevents the transmission of smoke prior to 
completion of the expansion of the intumescent material. 
The sealing action of the intumescent linings 25-28 in one of the 
compartments 24 is illustrated in FIGS. 6-9, where FIGS. 6 and 8 show the 
linings in their normal unexpanded condition, and FIGS. 7 and 9 show the 
intumescent material after it has expanded. In the particular example 
illustrated, only three cables, of uniform diameter, are shown as passing 
through the compartment 24, but it will be understood that the sealing 
action of the intumescent material is the same regardless of the number 
and/or size and/or pattern of arrangement of the cables. It can be seen 
that the intumescent linings 25-28 all expand inwardly from the 
compartment walls, surrounding the cables 11 and pressing against them so 
tightly that the cables actually are slightly crimped (see FIGS. 7 and 9). 
The smallest interstices between the cables 11 become filled with the 
expanded material, thereby completely sealing off the compartment 24. 
Moreover, as will be described in more detail below, the expansion of the 
thicker end pieces of intumescent material 27 and 28 is focused into the 
ever-decreasing internal volume; thus the intumescent material is used 
very efficiently and, therefore, a relatively small amount of the costly 
material is required. 
The intumescent linings 25-28 typically expand to more than five times 
their original thickness, so the linings are capable of filling the entire 
compartment 24, even if it is completely empty, because they expand 
inwardly from all four vertical side walls. Consequently, cables of a 
variety of different sizes can be installed in the conduit in completely 
random fashion without affecting the sealing action of the intumescent 
linings in the event of a fire. 
If it is desired to install cables having a larger diameter than the width 
of one of the compartments 24, one of the partitions 20 is simply reversed 
(and additional intumescent material is added) to form a compartment 
nearly twice as wide as the other compartments. This type of installation 
is illustrated in FIG. 5 which shows two larger cables 11a received in a 
compartment 24a formed by reversing one of the partitions 20. Of course, 
additional partitions could be removed to form an even wider compartment 
(with appropriate additions of intumescent material to augment the 
lining). Enlargement of the compartments in this manner tends to dilute 
the effectiveness of the radiation "peep-hole" effect described above, and 
thus it is desirable to maintain the narrow elongated compartments to the 
maximum extend possible in any given application. 
Whenever it is necessary to remove one or more of the partitions 20 to 
accommodate larger diameter cables, the amount of intumescent material 
available in the new oversized compartment 24a should be increased by 
inserting a strip of the intumescent material between the cables, bending 
the strip into a serpentine shape so that it engages alternate sides of 
successive cables and becomes interlocked therewith. When a larger 
compartment is made by simply reversing one of the partitions, an extra 
layer of intumescent material may be laminated to the main side walls of 
the two partitions defining the enlarged compartment. 
For the purpose of directing the expansion of the intumescent linings 27 
and 28 into the rectangular compartments 24, rather than out through the 
open top of the housing section 13, a pair of flanges 29 and 30 extend 
inwardly from the top ends of the respective side flanges 21 and 22, 
across the upper ends of the linings 27 and 28 on the inner surfaces of 
the flanges 21 and 22. At the bottom ends of the flanges 21 and 22, the 
horizontal supporting flange 23 formed on the lower edge of the housing 
section 13 performs the same function. These flanges all direct the 
initial expansion of the intumescent material into the compartments 24, as 
a result of which the subsequent expansion tends to continue in the same 
direction. Consequently, the major portion of the final expanded mass is 
contained within the compartments 24 to form a highly effective seal which 
will block the penetration of fire and smoke for extended periods of time. 
As can be seen most clearly in FIGS. 2, 3, 6 and 7, central portions of the 
side flanges 21 and 22 are cut away to form openings 31 and 32 through 
which the intumescent linings 27 and 28 can expand into direct engagement 
with the interior walls of the housing 13, thereby sealing the narrow gaps 
between the flanges 21, 22 and the adjacent housing walls. The force of 
the expanded material also wedges it firmly in place across the full width 
of the housing 13, exerting a substantial outward pressure on the interior 
surface of the housing, thereby tending to cause the housing walls to 
bulge outwardly toward the adjacent surfaces of the floor 12 in which the 
conduit is installed; during a fire this opening would have a tendency to 
expand. 
In order to prevent the penetration of a flash fire through the various 
compartments 24 or portions thereof that are not filled with cables, such 
compartments or portions thereof are filled with non-flammable inserts. 
Thus, in the illustrative embodiment of FIGS. 1-9, non-flammable boards 40 
are inserted into the empty compartments 24 to fill those portions which 
are lined with the intumescent material. A second non-flammable board 41 
is laid on top of each board 40 to fill the upper region of each 
compartment 24, above the top edges of the intumescent linings 25-28. 
These inserts 40 and 41 are made of non-flammable particulate and/or 
fibrous material, preferably held together by a small amount of 
non-flammable binder such as bentonite. Examples of particulate and 
fibrous materials suitable for use in these boards are sand, perlite, 
vermiculite, clay, fiberglass, mineral wool, asbestos, alumina etc. 
The inserts 40 and 41 also serve to hold the partitions 20 in place during 
shipment to avoid damage thereto, serve as a check on the dimensions of 
the partitions during manufacture, and resist buckling of the housing 13. 
Sealing of the empty compartments is also facilitated by the inserts 40 
and 41, as will be apparent from the ensuing description. 
As illustrated in FIG. 4, each of the inserts 40 is preferably provided 
with a series of vertical grooves 42 to facilitate removal of a portion of 
the insert for use in compartments that are only partially filled with 
cables, such as the compartments shown in FIGS. 5-7. The distance between 
the grooves 42 is normally about the same as the width of one of the 
compartments 24. 
In order to block smoke from passing through the conduit 10 at temperatures 
which are too low to initiate expansion of the intumescent material, or 
before sufficient time has elapsed to allow full expansion of the 
intumescent material, a cold smoke seal is formed between the walls of 
each compartment and any inserts therein, at the top of each compartment. 
Thus, in the illustrative embodiment of FIGS. 1-9, a sealant 43 is poured 
onto the top of each board 41 so that it flows into any slits or other 
openings remaining between the walls of each compartment 24 and the board 
41 therein. One example of a suitable sealant for this purpose is Dow 
Corning 3140 RTV coating made by Dow Corning Corporation, Midland, Mich., 
which is a flowable silicone rubber curable at room temperature. This is a 
thick, viscous liquid which fills the voids around the periphery of the 
board 41 without running too far down into the conduit. When it is desired 
to use one of the compartments 24 after it has been sealed, it is a simple 
matter to strip away the sealant and the top refractory board 41 (which 
will normally be at least partially bonded to the sealant). 
A silicone caulking or putty is used to seal the voids around the cables 11 
at the top of each compartment 24. A suitable caulking for this purpose is 
Type PR-855 RTV silicone foam made by Product Research and Chemical Corp., 
Glendale, Calif. As an alternative, the voids around the cables may be 
packed with an alumina silica fiber and then covered with the same type of 
sealant used on the inserts 41. During the initial moments of a major fire 
this caulking or sealant is protected from the radiation by the 
"peep-hole" effect of radiation absorption or attenuation in the narrow 
slot-like compartments 24. FIG. 6 illustrates an alternative where the top 
board is cut off, re-inserted, and then sealed by application of caulking 
and a self-leveling liquid sealant (used to fill in any gaps). 
In FIGS. 10-13, there is illustrated a modified floor conduit for use in 
applications involving a number of smaller cables or one large cable. In 
this embodiment the conduit housing is in the form of a cylinder, 
comprising an upper section 50 telescoped into a lower section 51. The two 
housing sections 50 and 51 are pre-assembled and set to the desired axial 
length by means of a set screw 52. The preassembled housing sections are 
then inserted into a preformed hole or slot in the concrete floor. Flanges 
50a and 51a on the ends of the respective housing sections 50 and 51 
overlap the adjacent concrete surfaces. Then the voids are filled with 
grout. This obviates the need for the "cold smoke seals" provided around 
the exterior of the unit of FIGS. 1-9. 
To provide continuity of the floor surface until the cylindrical conduit 
housing is ready to be used, a removable high-temperature, cold-molded 
plug 53 is inserted into the upper housing section 50 and covered with a 
plate 54. The cover plate 54 can be adhesively bonded to the top of the 
plug 53 and the top of the flange 50a. The plug 53 rests on an internal 
flange 55 formed as an integral part of the upper housing section 50 by 
indenting a circumferential section thereof. An internally threaded sleeve 
57 is embedded in the top of the plug 53 to receive a bolt for withdrawing 
the plug from the conduit when it is desired to pass cables therethrough. 
An O-ring 53a inserted in a groove in the outer surface of the plug 53 
provides a cold smoke seal. 
The interior of the cylindrical housing section 50 is divided into four 
compartments 56 by a cross-shaped partition 57 inserted therein in place 
of the plug 53 when the plug is removed. This partition 57 rests on the 
same flange 55 that supported the plug 53. Each of the compartments 56 
normally receives only a single cable 58, but a plurality of smaller 
cables can be nested in each compartment if desired. Also, the partition 
57 can be designed with a variety of other configurations to provide any 
desired number of compartments of the same or different sizes. The general 
geometry of the small compartments also provides for an added "peep-hole" 
effect similar to that obtained in the rectangular floor unit of FIGS. 
1-9. In this instance the significance of the "peep-hole" subdivision is 
diminished as the round, "pipe-like" shape of the circular conduit serves 
as an effective "peep-hole" by itself. 
The intumescent lining for the cylindrical conduit is provided in the form 
of a lining 60 on the inside surface of the upper housing section 50, 
extending down as far as the flange 55, and a lining 61 on all the 
vertical walls of the partition 57. As can be seen most clearly in FIG. 
13, the combination of the linings 60 and 61 forms a lining of intumescent 
material extending completely around each of the four compartments 56. 
Consequently, in the event of a fire each compartment 56 is completely 
filled by the expanding intumescent material, which will also seal itself 
tightly against the cable or cables passing through each compartment to 
block the transmission of fire and smoke through the conduit. 
Non-flammable inserts 62 are disposed within any of the compartments 56 or 
portions thereof which do not contain a cable. These inserts have a shape 
roughly complementary to that of the compartments 56, and are made of the 
same material as the inserts 40 and 41 described above in connection with 
the embodiment of FIGS. 1-9. 
In order to form a seal which blocks the transmission of smoke through the 
cylindrical conduit at temperatures below the temperature at which the 
intumescent linings 60-61 expand, a sealant 63 is poured onto the top of 
each insert 62; and a filler of silicone caulking or mineral wool is 
pressed around each of the cables 58 and a sealant poured thereon to 
provide a cold smoke seal. The effect of the "peep-hole" geometry 
described above serves to protect the "cold smoke seal" in this case, as 
in the case of the rectangular floor conduit of FIGS. 1-9, although the 
radiation absorption slots are shaped significantly differently. 
Turning next to FIGS. 14-20, there is shown a rectangular conduit 110 for 
use in walls rather than floors. This conduit 110 is similar in many 
respects to the rectangular floor conduit of FIGS. 1-9, but a completely 
different "cold" seal arrangement is provided for the open ends of the 
conduit because it is disposed vertically, rather than horizontally as in 
the case of the floor conduit. As illustrated in FIG. 20, two of these 
conduits are normally used in a cable hole in a "two-hour" masonary wall, 
on opposite sides thereof. However, one conduit, with an auxillary 
sleeve-type cold smoke shield is sufficient in a "one-hour" wall formed of 
wallboard and wooden studs. It is this latter type of installation that is 
shown in FIG. 14. 
The housing for the conduit 110 comprises a box-shaped housing 113, 
preferably formed of sheet metal, having an outwardly extending flange 
113a overlapping the surface of the wall with a gasket 114 disposed 
between the wall and the flange. A band 115 of intumescent material 
encircles the outside walls of the housing 113, and is bonded thereto, to 
seal off the gap between the housing and the wall hole in the event of a 
fire. 
To divide the interior of the housing 113 into a plurality of rectangular 
compartments extending horizontally therethrough, multiple partitions 120 
are inserted into the housing 113. Each of these partitions 120 has 
integral top and bottom flanges 121 and 122 (see FIG. 15) which slide 
along the respective top and bottom walls of the housing 113 until they 
engage an inwardly extending flange 123 formed around the inner or rear 
edge of the housing 113. The partitions 120 are fitted generally against 
each other within the housing 113 to form narrow rectangular compartments 
124, with the two endmost partitions abutting the respective end walls of 
the housing. 
For the purpose of accurately positioning the partitions 120 within the 
housing 113, a pair of loops 121a and 121b are struck out of each of the 
top flanges 121, and a similar pair of loops (not shown) are struck out of 
each of the bottom flanges 122. When the partition 120 is inserted into 
the housing 113, these loops 121a and 121b snap into a pair of 
complementary slots 113b and 113c (see FIGS. 14-16) in the top wall of the 
housing 113. Similar slots (not shown) are provided in the bottom wall of 
the housing for receiving the corresponding loops on the bottom flange 
122. The flanges 121 and 122 are somewhat elastic so that they can be bent 
inwardly while the partition 120 is being inserted into the housing 113, 
and then they spring back when the loops 121a and 121b come into register 
with the slots 113b and 113c. This causes the loops 121a and 121b to enter 
the slots 113b and 113c, thereby holding the partition 120 in the desired 
position within the housing 113 and relative to the other partitions. If 
it is desired to lock the partitions in these detent positions, small 
links of wire 121c may be inserted through the respective loops along the 
outer surfaces of the flanges 121 and 122 (see FIGS. 14-16). This is 
particularly desirable during shipment of the assembled conduit units. 
Alternatively, the loops 121a, 121b and slots 113b, 113c can be rotated 
90.degree. with respect to the orientation indicated in FIGS. 14-16. In 
this arrangement the central openings 31 and 32 are moved toward the 
bottom of the flanges 21 and 22. 
The intumescent linings for the multiple compartments 124 formed by the 
partitions 120 are provided by linings 125 and 126 on opposite surfaces of 
each main partitioning wall, and by linings 127 and 128 on the inner 
surfaces of the top and bottom flanges 121 and 122, respectively. These 
intumescent linings 125-128 function in the same general manner as the 
linings 25-28 described above in connction with FIGS. 1-9 except that the 
top piece 127 is double the thickness of the lower piece 128. The front 
and rear edges of both the flanges 121 and 122 form inwardly extending 
flanges 129, 129a and 130, 130a respectively, to direct the expanding 
intumescent material into the respective compartments 124. The end 
portions of the bottom flanges 130, 130a covered with a protective clip to 
avoid exposing the cables 111 to sharp edges which could cut the cables. 
Central openings 131 and 132 are formed in the central portions of the 
flanges 121 and 122, respectively, to permit the expanding intumescent 
material to expand into direct engagement with the interior walls of the 
housing 113. This seals the gaps between the flanges 121 and 122 and the 
adjacent housing walls, and also wedges the expanded body of intumescent 
material firmly in place between the top and bottom walls of the housing. 
To fill any compartments 124 or portions thereof that are not filled with 
cables 111, non-flammable boards 140 are inserted into any such empty 
compartments. These inserts 140 function in the same manner as the inserts 
40 described above in connection with FIGS. 1-9. 
As in the case of the floor conduit FIGS. 1-9, the wall conduit of FIGS. 
14-20 transforms a large opening into a series of adjacent slots creating 
a series of radiation "peep-holes" which serve to protect the materials on 
the "cold" side. In this case it also serves to protect the "cold smoke 
seal" to be described below. 
In order to form a "cold smoke seal" across the front surface of the 
conduit 110, the front of each compartment 124, or portion thereof, which 
does not contain any cables 111 is sealed by a flexible resilient blind 
150. One suitable material for these blinds 150 is silicone rubber. The 
vertical edges of each blind 150 are provided with ribs 151 which ride in 
complementary slots 152 formed by vertical metal or plastic extrusions 153 
and 154 (see FIGS. 18 and 19) seated in notches 150a in the front of the 
housing 113 (see FIG. 19). The rear surface of each extrusion 153 and 154 
also has an additional slot 155 adapted to receive the front edge of one 
of the partitions 120, thereby assuring alignment of the blinds 150 with 
the compartments 124 formed by the partitions 120. 
To secure the blinds 150 to the front of the housing 113, a pair of 
horizontal strips 156 are fastened to the outwardly extending flange 113a 
extending around the front edge of the housing. Each of the strips 156 
includes a longitudinal rib 157 (see FIG. 16) which squeezes the blinds 
150 tightly against the housing flange 113a to complete the seal. A second 
rib 158 on each strip 156 overlaps a lip 159 on the outer edge of the 
flange 113a to complete the enclosure. 
As can be seen most clearly in FIG. 14, the combination of the two vertical 
end pieces 154 and the two horizontal strips 156 form a front frame for 
the wall conduit 110. These four members are all secured to the housing 
113 by a plurality of screws 160, although any other suitable fastening 
means could be used for this purpose. 
One of the advantages of the illustrative sealing arrangement for the wall 
conduit 110 is that each individual blind 150 can be easily moved back and 
forth in the vertical direction by simply removing the horizontal strips 
156. Because the rectangular compartments 124 are elongated in the 
vertical direction, the stack of cables 111 passing through any given 
compartment 124 will always fill the bottom of the compartment before the 
top. Consequently, if any given compartment 124 is not completely filled, 
the blind 150 for that compartment can be simply lowered until it engages 
the topmost cable 111, and then cut off to the exact length to fit under 
the top lip 159 on the housing. This makes the installation quick and 
simple, thereby keeping the installation cost to a minimum. 
The "cold smoke shield" as described above is adequate provided there is no 
fire on that side of the wall. In the event of fire on that side of the 
wall, however, an additional "cold smoke shield" is required on the other 
side of the wall. In the case of "two-hour" masonary wall illustrated in 
FIG. 20, a second conduit provides the required "cold smoke shield"on the 
other side of the wall, with through bolts 170 holding the two conduits 
together to prevent the intumescent material from forcing one or both of 
the units out of the wall. In the case of the "one-hour" stud wall 
illustrated in FIG. 14, an auxillary "cold smoke shield" is provided on a 
sleeve-type support 180 which slides into the wall and may optionally fit 
over the outside of the conduit 110 relatively snugly for positioning. 
This sleeve 180 is preferably made of sheet metal and is equipped a "cold 
smoke shield" structure (not shown) similar to that on the front of the 
conduit 110, as described above. That is, the sleeve 180 includes all the 
same elements as the conduit 110 except the partitions 120, the inwardly 
extending flange on the inner edge of the housing, and the intumescent 
linings.