Note: Descriptions are shown in the official language in which they were submitted.
L~ L J
Deseription
Fire_Pro~ective Mastic and Fire Stop
Technical Field
This invention relates to a fire protective ma~tic
5 and fire stop for electrical cables and neighboring wall
~unctur~ or partitions through which the cables pa~s, the
mastic comprlsing prot~c~ive water vapor-evolving sub-
stances, other substances which intumesce or exp~nd, and
still others which glaze with sufficient heat and form a
10 stable protective porous coating havin~ a fused cera~ic
casing upon the electric cables and fire stop panels, when
exposed to fire. The ma3tic is also useful as a precast
boot for mounting upon cables or splices, or as an air and
fire seal or caulk disposed upon or between cables, the
15 m~stic filling cracks or crevice~ between cables or panels
and cables, and serves as a coating upon fire stop panels
and upon neighboring walls, and or wall paneling per se
through which electric cables pass as a fire protec~ive wall
and in which ~he paneling or boot per se may be fonmed of
20 the precast dry ma~tic.
Back~round Art
In prior applications of other heat and fire protec-
tive ~nsulation subs~ances upon electrical cables, the~e,
according to my prior patents No~. 4,018,962 and 4,018,983
25 have been loosely wound as tape or mounted as a boot about
a cable joint as fire protective means while or after the
cables were assembled, both the tape and boot being rela-
tively ~on-cohere~t to the cable. It was also proposed in
~, S0 patents NosO 3,642,531 and 3,928,210 to coat cables
30 as an aqueous emulsion of resins, including essentially
halogen evolving plasticizers, the heat insulating effect
, .. . . . , . , , , , , .......................... , . , .. , ., . ., _ ..
, ; .., : .
:: ,
-
of. such coating compositions being largely provided by in-
organic fiber which functions comparatively poorly for this
purpose~ and the halogen gas evolved with heat decomposition
is highly corrosive and toxic, a source of substantial dan-
5 ger and dama8~ to personnel and equipment. Equally impor-
tant, such compositions coat poorly and crack upon drying,
and, under the destructive effect of high temperature, tend
rapidly to peel, flake or powder away from the pr~tective
position upon the electrical cables which they were intended
10 to pro~ect. Such coatings9 in contrast to the present fail
to adequately meet the important fire and heat insulating
needs to preve~t destruc~ion of cable ~acketing and insula-
tion-protecting critical power and multiple co~ductor con-
trol cables and to prevent propagation of fire along grouped
15 cables in trays and through wall and floor pentrations at
flaming temperatures often exceeding 1~900Fo
Disclosure of Invention
The mastic hereof contains large quantities such as 60
~o 85% of a mi~ture of solids of several types, each with 3
20 distinct function to provide in combination a super~or fire
protective effect. The solids are onmed into a-mastic by
a binder resin dispersed in water in quantity to form a co-
herent coating when dry, whereby the solids and the disper-
sion may be evenly mixedO Additional quantities of aqueous
25 diluent may be added in the mixing, for conversion of the
dispers~on.of resins and dry solidQ to a trowelable, coat-
able or even sprayable composition, as needed to provide the
requisite fluidity for application.
Some of the solids include intumescing or decrepitat-
30 ing substances, typically cenospheres, which are fly-ash,
inorganic particles evolved as dust from coal combustion
and are very light, volatile and expandable with heat, like
tiny fused ballons. It is that expansion of such gas evolv--
ing substance~ in combination with other vapor producing
:
~5
--3--
substances mixed therewith which, when the composition is
heated under fire exposure at temperatures above about
1,000F to activate the intumescing components and release
vapors which convert the composition from a thin layer
5 coating on a cable or panel to its expanded heat insulating
form. Such intumescent solids are present in the ranga of
5-40~, preferably about 7-25%o
Other solids present ln the composition are of a chem-
ical hydrate character, having che~ically or physically com-
10 b~ned water, such as hydrou~ o~ides9 silicates and otherhydrated substances which firmly bond the water and which
decompose with the heat of a fire and evolve large quanti-
t~es of cool~ng, non-corrosive oxygen displacing and fire-
protective water vapors. Such hydrou~ o~idas are typically
15 hydrous alumina, ~agnesia and the other water evolving hy-
drous o~ides and silicates. These hydrated components are
used ln quanti~y of 10 to 40~ and preferably in quan~y of
15 to 30ZO
S~ill other solids in the mastic comprise a heat fus-
20 ible ceramic ~r~.t which, when heated sufficiently upon anouter surface of the e~panded coating, exposed to high fire
developed heat, glaze over and encase the expanded dry mas-
tic as a fire protective film thereon, protecting the ex-
panded coating ~nd insulating t~e cables, or in or upon the
25 fire stop panels or boots. Such frit generally is a low
fusible glass, typically a borosilicate glass frit genarally
fusible in the range of about 700 to 1,500P. It is use-
fully used in the range of about 5 to 40%, and preferably
about 10 to 25%o
The composition includes a thermoplastic resin as a
binder dispersed in water, the aqueous dispersion being
mixed evanly with said solids to form the masticO The
thenmoplastic resin is present in quantities sufficient to
form a flexible binder for the mastic composition when dry, -
35 as a coating upon the electrical cables or panels, or to
., .
': ,.
L~
bind the panels or boots upon drying into a strong struc-
tural form. Sufficient additional water is added in the
mixing as stated, for supplying requisite fluidity for ap-
plica~ion. The resinous solids are present in the quantity
5 of about 15 t~ 40% of the dry composition, preferably 20 to
30~. Such thermoplastic substanc~ may be any useful ther-
moplastic binder r~sin, which is halogen-free, but which
may melt and flow by heat developed during fire and allow
the composition to expand to a heat insulating coating.
10 The typical resins ~or th~s purpose are halogen-free to
avoid decomposition and release of noxious and corrosive
halogen gases, and may be typically polyvinyl acetate, poly-
acrylic acid, polyacrylic lower alkyl esters, such as methyl
or ethyl esters thereof, polymethacrylic acid and its lower
15 alkyl esters, such as methyl and ethyl esters thereof, as
well as mixtures of such acrylic re~ins, natusal and artifi-
cal rubber latices, each as dispersions in water, said dis-
persion~ usally having from 25 to 75% of resin solid~ there-
in, usually 45 to 65% resin solids, the balance being water
20 with minor quant~ties of dispersing agentsO
The composition further includes small quantities of
combustible fiber, such as cotton, rayon, aramide or the
l~ke, to provide a temporary coating stability for the wet
or molten mast~c. For this purpose the fiber need not be
25 fire proof and may burn aQ the composition becomes heated
when exposed to ire and will only be used in minor quan-
tity, generally less than 5%, usually 0O5 to 2.0% to supply
this temporary binding function.
The composition will further contain among the solids,
30 such fire retardant substances as antimony oxides, which
develop vapors with heat along with the protective water
vapors evolved. Antimony oxide also is a low fusible com-
ponent and contributes to the formation of the fused frit
ca~ing during fire exposure~ Another fire retardan~ solid
35 is zinc ~etraborate which, through synergistic action,
. , . , . ~ .
..
,., ~ .
. ~:: , .
.. . . - . .
. .
fu~ether improves the fire-retardant character of antimony
oxide in the mixture. These fire retardant antimony ox-
ides and zinc tetraborates are each used in quantity of 2
to 15%, preferably 4 to 10% and 5 to 10% respectively~
Other solids present ~n the composition are each ad-
ded for a specific minor function and will be present gen-
erally in quanti~y from about 0.1 to 10%, some, generally
less than 2X, adequate only to perform the function. Thus,
other solids may consist of emulsifying agents, typically
10 Triton X 100, such as octylphenyl-polyethoxy ethanol, in
quantity of about 0.5 to 5%. Rust inhibitors, generally
in quan~ity ~f about 0.2 to 5~, such as potassiwm poly-
phosphoric acid esters. Preservatives, such as fungicides,
which are mercury complexeQ, in quantity of about 0.01 up
15 to about 0.05. Viscosity controlling agents, such as al~
kali metal salts of polycarboxylic acid or oil based liquid
polysiloxanes in quantity of 0.2 to 5%. Thickenerss such
as hydroxy ethyl cellulose and a clay type inorganic gell-
ing agent, such as attapulgite clay in quantity of 0.1 to
20 2%. These several minor additive components for these
functions are used in quantity sufficient for the stated
function, and each generally will be present in quantity
of less than 10%, and usually from 0.2 to 2%o
Thus the vapors evolved are non-corrosive gases con-
25 sisting o~ water vapor, antimony oxides and minor heat de-
composition vapors of the resin and fiber. Such halogen-
ated resins as release halogen, typically chlorine, such
as polyvinyl chloride or numerous halogenated plasticizers
as also are commonly used in the fire proofing art and whose
30 destruction and release by heat during cable failure, as
by arcing, short circuitry or destruction by fire from other
sources in the neighborhood of the cables and protectively
coated with such fire proofing substances, as release hal-
ogen, are avoided, whereby the composition hereof releas~s
35 no noxious and corrosive halogen gases.
In forming this mastic mixture, the binder emulsion
of resin in water is further mixed with the dry intumescing
anld fire proofing solids, and reduced wi~h a small addi-
tiDnal quantity of water as needed to homogeneously mix the
5 filler solids and emulsion for application. The mastic
dries and sets by evaporation, at thickne~ses of l/2" to
l lf2" th~ck flexible coating on the electrical cables and
wall panels forming a heat insulating and fire proofing
mastic a~ well 8S an effective heat insulating air ~eal and
10 fire stop in panel fo~m at interrupting walls through which
the cables pass.
The mastic hereof is intended both as moldable mixture
for forming into fire proofing boots to be installed upon
cable ~oints and splices or on dry wall panels through
15 which electrical cables may pass, or as a thick suspension
in water to be applicable as a protective mastic filler and
coating body upon and about a group of cables, entering,
leaving and passing through a floor slab or fire wall, which
may be formed of such or other fire protected wall panels.
20 The panels can also be formed a~ a laminate of rigid panel
boa~d such as ceramic fiber, gyp3um or Transite, having
such mastic coat applied and dried upon one or both sur-
faces thereof.
Brie Descr~ption_of Drawin~s
The invention is further explained with reference to
~he drawings wherein:-
Fig. 1 show~ a parspective of groups of mastic covered
cable4 passing through a wall which may be protected by the
fire stop paneling and mastic hereof;
Figo 2 is an elevation of seve~al trays of cables ar-
ranged in a vertical tier a~ they will pass through a fire
wall protected by the paneling hereof;
Fig.-3 is a detail showing the mastic as an outer la-
mina layer upon a conventional heat resistant wall board
35 base;
_ .. ~ . ~ . . . _ _ .. ~ .. _ _ .. . . ~ . . . . .. _ _ _ . . _ _ . _ _ _ _ .
j L~
Fig. 4 is a detail showing the mastic poured about
cables passing through a floor opening;
Figo 5 illustrates a detail of a conduit carrying
cables which is filled with mastic; and
Fig. 6 shows a section of a mastic coated cable.
Best Mode for Carry~n~ Out the Invention
Referrin8 to Fig. 1, a wall 10 of concrete or masonry
separate~ 9paces A and B as a par~ition for normal struc-
tural purposes and has a rectangular opening 12 cu~ there-
10 in for passage of a tier of trays 14 and 16 which supportand partially enclose electrical cables 18. These cables
are conventional groups of power or multiple conductor con-
trol cables mounted, insulated and jacketed for purposes of
electrical insulation and moisture imperviousness. Thus
15 the cables may carry critical communication circuitry or
conduct electrical power, ofttimes of high voltage. In any
case~ any building construction has many cables as a valu-
able part thereof and, for whataver electrical purpose they
serve, great damage can be done to the structure and cables
20 b~ electrical faults, such as short circuitry or extrane-
ously caused fire, such as by exposed to flaming combination
of oil, trash or the like, developing destructive heat in
the cables. Again, the cables themselves are valuable in
terms of the numerous communicating conductors and the re-
25 dundant circuits which muqt be provided, as well as impor-
tance of wires which may be a part of the cables per se,
all being desirable protected. The coating hereof effec-
tively protects cables longitudinally or vertically agains~
propagation of any fire, regardless of source, so that fire
30 cannot damage redundant control and power circuits and pene-
trade into critical control areas.
Finally, it is dPsirable not only to encase the cables
by fire preventive mastic, but also to protect one side of
a partitioning wall 10 as a fire stop with insulation and ;
.:
.
~ ~L 9 ~ L~
--8--
insulating panals formed by the combination of a f1re stop
panel and mastic hereof, thus to prevent transfer of heat,
flame or evolved gases to the opposite wall side of the
fire stop.
Electrical cables 18 therefore, and for this purpose,
are mounted in supporting trays 14 and 16, which may com-
prise channel irons 20, connected by a metalic ladder, ex-
pa~ded mesh or solid framework 22 which can terminate or
pass through the opening 12 of the wall lO. The layers of
10 cables can be fur~her supported from below by a heat re-
8i8tant panel 24 which may be a pre-ca~t panel of the mas-
tic material hereof or other typa o fire proofing tray
liner.
At the wall opening 12 a further set of wall panels
15 26~ 28 and are mounted each with cut-away portions (not
shown) to fit over the cables and close the wall opening
12, as well as to closely close any spaces between cables
passing through the wall~ The cables pass directly through
or them~alve~ may each be enclo~ed in a supporting heat re-
20 sistant metal sleeve or conduit tube (not shown). It i5s~metime~ desirable to cover the interstices between the
cables with loosely matted inorganic fiber which forms a
filler for large spaces directing and supporting the mas-
tic to close engagement with the cables and for allowi~g
25 an overall coating as a bed of cables. Optionally, however,
the ma tic itself may be supplied alone to fill the space
between the cables through the entire depth above the lower
panel 24 up to a point above the surfaces of the cables as
shown in Fig. 1, whereby, the cables become fully embedded
30 w~thin the dried mastic. The mastic can be sprayed over
the grouped cables as a 1/8" minimum thickness coating~
Moreover, the mastic 30 is extended to cover the pan-
eling 26, 28 and to fill all of the cracks and crevices
therein, whereby the cables pass through the paneling and
35 through the opening 12 of the wall 10, each crack, opening
: .
. ~ ..
- 9 -
or space being filled with mastic. It may also be applied
wil:hin conduit carrying cables to fill or plug the same as
shown in Fig. 5. Moreover, the mastic is applied over the
top of the cables and for secure closure of any cracks be-
5 tween panels, both around the panel edges as well as anyspacing or c~acks between the ad~acent panels.
As shown in Fig. 1 two trays of cables pass through
the wall 10 with the construction described. The cables
may be present in any number and arranged in the trays in
10 any grouping. Additional cables may be passed through the
wall of that construction by cutting through the light pre-
cast panels, cutting away some of the mastic and penetrat-
~n8 t~rou~h the panel in a circular cut in a manner to ac-
commodate one or more additional cables to be added from
15 time to time, and the new cable being readily thrust through
a newly fonmed cut portion. The newly added cables are
coated with more fresh mastic and any cracks or crevices
remaining about the n~wly added cables in the panels are
further coated and sealed with more mastic, whereby addi-
20 tional cables are ea~ily added from timQ to time.
As shown in Fig. 2 many trays can be assembled in atier of trays passing to or through the wall, depending
upon the wall size according to the size and height needed
above the floor 32, whereby two stacks or more trays as may
25 be needed ~o accommodate all of the cables can be used. In
~hat case the separate stacks of cable~ C and D may be fur-
ther separated by a partitioning wall 34, ~n which larger
panels of the mastic hereof are assembled as`a separating
partition 34 and the partition may be supported as shown
30 by angle iron brackets 36. It may be useful to separate
the panels by a central lamlnated layer 38 which may be of
metal wire or glass fiber or other reinforcing material.
- The fire stop wall may be formed of fire proof panel-
ing material, resistant to heat, whereby to operate as a
35 fire-protective shield or partition between the opposite
, . . ~
"` -.
-1~
wall sides of spaces, as an easily assembled fire stop
partition through which a group of cables pass, whereby
the protective wall prevants heat and flame transfer, as
well as the transfer of noxious vapors or smoke to its
5 opposite wall side where continuing or redundant circuits
may be installed. Particularly, the fire stop wall is in-
~tended to prevent transfer of heat, to the wall side op-
posite to that facing fire exposure and remains relatively
cool on the opposite wall side fxom the high temperatures
10 ~hat may develop from a cable failure. The panel~ng may
be formed of other useful pre-cast fire proof ~aterials,
but often is of the same dried mastic material as the mas-
tic, also being applied as a coating upon the cables here-
of, the mastic being cast in~o panels for assembly as dried
15 panels in the fire stop wall hereof.
Fig. 3 illustrates a panel board which can be of any
commercial ceramic fiber rigid insulating board 40 and
which has coated thereon a thin 1/8 to 1/4" coating 42 of
the mastic hereof.
As shown in Fig. 4 cables disposed as groups or indi-
vidual cable~ in sleeves are mounted pass through a floor
slab 10 with the mastic hereof poured about and with the
sleeve to form an air seal as well as a fire stop. Fig. 5
shows the detail wherein a conduit which may penetrate a
25 wall or floor, and carrying one or more cables is filled
with a mastic, applied by caulking or troweling.
The present composition is highly heat and fire pro-
tective. It evolves only non-corrosive vapors, such as
water vapors, antimony oxides and zinc tetraborate. It pro-
30 duces a porous heat expanded heat insulating body protectiveof the cable when destructive heat is applied, the coating
being developed by expansion o the intumescent substances
and evolving gases, which convert the coating to an expanded,
porous, heat insulating body. The coating further contains
.. . .. . .. . _ . . . ..
,
.; ,
. .
.. . , ~ :
a heat fusible frit which forms a glaze, strengthening and
protecting the coating despite very high temperatures~
whereby the coating is low heat transfering and does not
powder, flake or peel off the surface of ~he cable to which
5 it was applied.
Theoreticallyj it appears that during the heating pro~
cess when ignition and combustion take place through elec-
trical faults such as arcing or short circuitry or other
source of high heat evolution, the coating first in the
10 presence of heat softens the thermoplastic component. The
intumescin~ subs~ance3 such as ceno~pheres and the hydrous
oxides with enough heat be8in to expand as well as to evolve
water vapor. The antimony oxide at higher temperatures can
evolve its vapors. The fiber which is ult~mately heat de-
15 composable, operates in the cold tc help bond the composi-
tion into a firm strong and crack-free coating while it
drie3. As ~he initial heating is applied, the thermoplas-
tic binder melts, but the fiber te~ds to prevent the resin
from flowing away, maintaining the in~egrity of the compo-
20 sition while it steadily expands with the heat. Ultimatelythe fiber and tke resin may be charred to an infusible
porous mass, developed by the expanding intumescing solids.
The expanding mass carried m~ch of the fusible frit t~ the
coa~ing surface, where at high heat exposure temperatures,
25 the frit can fuse protectively as a refraction shell over
the porous mass to prevent further heat passing into or
from central or inner cable portionsO The glazed frit ser-
ving urther as a reinforcing shell to prevent further in-
gress of great heat and prevents the mas~ from peeling or
30 flaking away from its protective position about the cable.
The composition functions similarly either as a com-
ponent of the total panel body or as an even outer layer
on the paneling, whexeby the mastic substance thereof will
expand with heat protectively as a fire barrier or stop.
35 One side of the panel of great heat exposure absorbs and
: :
~$~ J
-12-
prevents passage of heat, acting as a heat and fire stop
partition or protective wall, allowing little heat to pass
to thP opposite side which remains comparatively cool. A
similar effect is achieved both by using ordinary non heat
5 conductive paneling substances such as commercially avail-
able insul~ting board of ceramic fiber which, however, is
coated with the mastic hereof to improve the wall paneling
as a fire stop through which the cables pass.
The water co~ponent hereof is free water. The resin-
10 ous emulsion may be quite thick and more water to that con-
tained in the resinous emulsion is usually added merely
supplied as free water ~n quantity sufficient to adjust the
m~xture to a trowelable down to sprayable mas~ic as desiredO
For purposes of easy distribution of the water, various sur-
15 factants such as Trito ~X 100 an alkylphenoxy, polyloweral-
kyleneoxy, lGweralkanol in which the alkyl has 1-2 carbon
atoms, and the product may contain from about 10-40 alky-
~lenoxy groups.
The resinous binder hereof is dispersed as an emulsion
20 water in concentration of 45 to 65% resin solids ~he remain-
der being water. Minor additives may be supplied to improve
the body and flexibility, typically an anti foam agent such
as Colloid ~ 77, an oil based polysiloxane, thickeners such
as hydroxylethyl cellulose, rust inhibitors such as Strodex~
25 PK-90, a potassium polyphosphoric acid ester, and preserva-
tives of an anti-fungal nature, such as Troysan, an organic
mercurial complex. Such additives will be used in the minor
quantity 0.1 to 5% and sometimes as high as 10%, but gen-
erally less than 1%, and usefully less than 0.2% such as
30 ~ol to 1%, and are generally mixed in a carrier such as a
propylene glycol in quantity usually less than 2%, such as
0 . 5 - 170 .
~ TR~ ARI~
, i ; ~ ~ .
-;
,
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.rHE FOLLOWING IS A GENERAL FORMULA FOR THE MASTIC
WEIGHT PER CENT TO~L
PREFERRED RA~G~
WATER (added to control body) 5 - 15 1 - 30
R~SINOUS DISPERSION
~-logen-free resin solids 20 - 30 15 - 40
ADDITIV~ES
B co~mon surfactant, i~e. Triton X 100,
octyl phenyl polyethyleneoxyethanol,
-Tamol sodium polycarbo~ylate; Anti-
osming agent, ~.eO colloid, oil based
polysiloxane; thickener, QP 440 ~hydroYy
ethyl cellulose; Strode ~ PK 90, potas-
sium polyphosphoric acid methyl ester;
attapulgite gel, diatomaceous clay;
fungicidal preservative, Troysan~CMP
acetate mercurial complex, propylene .. .
glycol~ O D2 5 Ool 10
ORGANIC FIBER
-Typically aramid, rayon, wool or
cot~on. 0.5 - 200 Ool - 5
WATER VAPOR EVOLVING
~ydrous oxides (inorganic hydrates
having chemically combined water
evolvable only under fire condi-
~ions 15 - 30 ~0 - 40
INTUMESCENTS
Cenospheres 7 - 25 5 - 40
~ r~ R~
; . .
-
-14-
WEIGHT PER CENTTOTAL
PREFERRED RANGE
FIRE-P~EVENTATIVES
. _
Z ~nc Tetraborate 5 - 10 2 - 15
Antimony Oxide 4 - 10 2 - 15
F~IT
C~ra~ic Glazing Solids (typically
law-fusing borosilicate glasses
geTIerally calcium, magnesium,
æirconium~ borosilicates (gen-
erally lead-free). 10 - 25 5 - 40
.; .
.. . . '' ' ' ` ' ' ' ` ' .
.. .. .
.
.'. ' ; ~ ;" ` ' `.
;
. . , , , , -
In forming the composition, the dry components are
mixed and eveDly blended with the plastic to form a heavy
mastic, adding a small quantity of water in the range
stated, sufficient to bring the mastic up to an applicable
5 viscosity upon the cables assembled and panels as shown,
filling all of the openings, cracks and crevices. The
~astic formed as described may be extruded into sheets of
desired thickness, such as l/4 to 1 1/2 inches ~hick. The
wet e~truded panel may be set merely by drying evaporation
10 of the water at ambient temperatures. It 1s sometimes pre-
ferred to form the panels thiDner, sometimes as thin as
1/4 lnch paneling and form panels in pairs of lamina of 2,
3 or more, as desired, and fas~ened across the opening ~0
with metalic fasteners 38 as shown. A preferred form is a
15 single layer of 1/8 to 1/4 inch thick coating upon a board ;
of 1/2 to 1 inch thick body.
The cables themselves are encased in coating, which r
may be thin and flexible or may be applied as a filler mas-
tic between a group of cables which pass t~rough the panel-
- 20 ing, cut with holes to allow cables or trays having a num-
ber of separately spaced cables to pass through from side
to side of the fire stop wall, and the cracks and crevices
about each cable are then filled with the mastic. Thus the
mastic is applied by spraying, trowelling or brushing upon
25 the cables, between the cables, upon the fire stop wall as
a coating and as the paneling substance from which the wall
per se is formedO
The following examples illustrate the practice of
this invention:-
30 EX~IE; 1
Four hundred and sixty-two pounds of vinyl acrylic
polymer dispersed in water in quantity of about 277 lbs.
of polymer, the remainder of said emulsion being water and
additives. The additives consist of 13 lbso of propylene
';
--16--
gl.ycol, 6 lbs. of Colloid 677, oil based liquid polysil-
oaane, 1.5 lbs. of hydroxy methyl cellulose, 6.5 lbs. of
rayon fiber, 1.5 lbs. of Strodex PK 90, potassium poly-
phosphorie acid ethyl ester and 0.5 lbs. of a mercurial
5 complex preservative. The entire mixture being a viscous
dispersion in water. Separately, a dispersion of 1.0 lbso
of Trlton X 100, which is octyl phenyl polyethyleneoxy-
ethanol, and 5.7 lbs. of Tamol, sodium salt of polycarboxy-
lic acid, are dispersed in 50 lbs. of water. The aqueous
10 ~olu~ion of dispersing agents and additives is used to di-
lute the first resinous emulsion. Thereafter dry powders
consisting of 190 lbs. of hydrous aluminum oxide, 90 lbs.
of cenospheres, 80 lbs. of zinc tetraborate, 68 lbs. of
antimony oxide and 163 lbso of frit, a low temperature
15 borosilicate glass essentially lead-free calcium silicate
ceramic glass, available from the Ferro Corporation as FB-
282. Thickeners such as Attagel 40 are added to the ex-
tent of 10 lbs. to control consistency. The dried powders
are mixed in~o the diluted liquid emulsion to form a spray-
20 able mastic which is s-prayed upon electrical cables and up-
on fire stop panels. m e mastic dries at ambient tempera-
tures in air to form approximately a 1/8 to 1/4 inch thick,
on average, coating, firmly and flexibly adherent to the
cable surface. The base of the panel is commercial ceramic
25 fiber board, such as Kaowool, Duraboard board of 1 inch
thic~ness
The coated panel of this example, about 1" was tested
according to AS~ME 119 by supporting the panel above a flame
having an average firing temperature of 1725F. The flame
30 impinges against the coated side and the temperature of the
ullcoated side was measured to determine the heat transfer
effect~ It was found in a series of three hour burning
tests that the maximum temperature measured on the uncoated
side was about 330F or the board with a 1/4" coating the
35 heated mastic genera~ed only a small amount of smoXe, the
~: . ' ' -;
~s~ ~
coating remained well adherent to the insulating boardO
For a 1/8" thick coating with mastic the average trans-
ferred temperature was 350F. In a comparison with a
competitive composition the temperature for a 1l8l' coating
5 wa~ 380F, and for an uncoated board the temperature was
400F. In separate tests it was found that a standard
vertical burn te~t (IEE - 383) appl~ed to grouped cables
coated with this mastic was self extinguishable after re-
moval of the flame source; there was no apparent damage
10 to ~acketlng or insulation dur~ng a 20 mlnute burn in which .;
abou~ 70~000 BTU per hour was applied to the coated cables,
and there was no flam~ propagation after removal of the
burner. rrhe coating of this example i~ flexible, and af-
ter drying, the coated cables can be bent without cracking
15 of the coating.
EXAMPLE 2
A s~milar mastic as example 1 was formed using a com-
mercial mixture of polyacrylate resins dispersed in water
available as UCAR 163, having similarly about 60%-of poly-
20 acrylate total solids, of which 58~ was mixed polyacrylics,the rema~nder being additives as in example 1. This thick
res~n wa~ similarly diluted with water and additives, thin-
ning the thick emulsion and into which is added the powders
as example l. The mastic coated upon the cables as shown
25 is flexible and fire resistant by the same tests, and is
highly heat insulating, a 1" thick panel coated with tha
mastic to a thickness o 1/8" average, and similarly ex-
posed to a 1725F exposed flame for a three hour time per-
iod, transferred the average temperature to the opposite
30 side of about 345F over the test period. Seven conductor
control cables coated with a thickness of 1/8" min. were
- still flexible, and, in a special Factory Mutual test, were
immersed and cycled in and out of 60C 1% salt water solu- r
tion for thirty days, and the coa~ing was unaffected and
-18-
re~mained firmly adherent. In each of the tests examples
1 and 2 the heated surface had a ceramic glaze and the
coating had expanded to a porous film of about twice the
- original applied and dried film thickness.
5 EXAMæL~ 3
The mastic of example 2 was formed by similarly thin-
ning the com~ercial resinous dispersion of polyacrylic
resins, reduc~ng the extra quantity of water used in the
thinning to 15 lbs.~ whereby, the mastic was thicker and
10 trowelable~ In this form it was cast into panels and used
as a fire stop panel in a test by exposure to a 1700-1750F
flame. The maximum temperature on the cool side a 1'1 panel
was 285F~ on average over a three hour test period, the
panel expanding and charring in the area of the applied
15 heat, but conducted no flame when the burner was withdrawnO
As s~.own ~n Fig. 4 ona or mor~ cable~ can be passed
vertically through a masonry floor, for which purpose they
may be mounted within a pre-formed sleeve and the mastic
poured around the sleeve~ ~he mastic may also, as shown
20 in Fig. 5 be filled into the body of the sleeve or applied
only in separated portions thereof for support, and sealing
~he cables for prevention of gas flow between spaces sepa-
rated by the floor. The mastic will be filled or applied
around the outside of the sleeve as shown to a selected
25 depth, and other fire stop paneling as shown in Fig. 1 may
also be used to close the floor opening.
Fig. 6 shows a single cable having a dried precoated
film of mastic thereon, a-form in which the cable itself
may be handled.
- Various modification3 will occur to those skilled in
the art, particularly other hydrous oxides and other known
cera~ic frits may be substituted, but no halogen containing
substance will be used.
... .
- ",',
--19--
Accordingly, it is intended tha~ the disclosure be
regarded as exemplary and not limiting, except as defined
in the clalmsO
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.
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