| United States Patent Application |
20210071413
|
| Kind Code
|
A1
|
|
Worch; Anatol
|
March 11, 2021
|
HEAT INSULATING ELEMENT, BUILDING CONSTRUCTION AND METHOD FOR AVOIDING
MOISTURE DAMAGE AT A BUILDING
Abstract
The invention relates to a heat insulating element (4) for an interior
insulation, a facade insulation, a roof insulation, or the like at a
building (1), comprising an insulating body (41) which is of
diffusion-open design. The heat insulating element (4) is characterized
in that it further comprises a fabric (42), especially a fleece, which is
of capillary-active design, and that the fabric (42) is arranged on a
surface of the insulating body (41). Furthermore, the invention relates
to a building construction, to a method for avoiding moisture damage at a
building (1), and to the use of a heat insulating element of this type.
This achieves an improved heat insulating element (4) for avoiding
moisture damage at a building (1) by means of which it is possible to
accelerate drying of the region concerned in the case of the accumulation
of water, especially condensation water, with simple means. Furthermore,
an appropriate building construction is provided in which moisture damage
can be avoided more reliably, and an improved method for avoiding
moisture damage at a building (1) is provided.
| Inventors: |
Worch; Anatol; (Kamen, DE)
|
| Applicant: | | Name | City | State | Country | Type | SAINT-GOBAIN ISOVER | Courbevoie | | FR
| | |
| Family ID:
|
66752051
|
| Appl. No.:
|
17/053637
|
| Filed:
|
May 22, 2019 |
| PCT Filed:
|
May 22, 2019 |
| PCT NO:
|
PCT/EP2019/063230 |
| 371 Date:
|
November 6, 2020 |
| Current U.S. Class: |
1/1 |
| Current CPC Class: |
B32B 2262/101 20130101; E04B 1/7645 20130101; E04D 12/002 20130101; B32B 21/10 20130101; E04D 13/1625 20130101; B32B 2307/304 20130101; E04B 1/80 20130101; E04D 11/02 20130101; E04D 13/1618 20130101; B32B 21/02 20130101; E04B 1/762 20130101; B32B 2419/06 20130101; E04B 2001/745 20130101; Y02A 30/244 20180101; B32B 2262/02 20130101; E04B 1/7675 20130101; B32B 5/02 20130101; B32B 2262/108 20130101; B32B 19/06 20130101; E04C 2/296 20130101 |
| International Class: |
E04B 1/80 20060101 E04B001/80; E04B 1/76 20060101 E04B001/76; E04C 2/296 20060101 E04C002/296; E04D 11/02 20060101 E04D011/02; E04D 13/16 20060101 E04D013/16; B32B 5/02 20060101 B32B005/02; B32B 19/06 20060101 B32B019/06; B32B 21/02 20060101 B32B021/02; B32B 21/10 20060101 B32B021/10 |
Foreign Application Data
| Date | Code | Application Number |
| May 22, 2018 | DE | 10 2018 112 260.8 |
Claims
1. A heat insulating element (4) for an interior insulation, a facade
insulation, a roof insulation, or the like at a building (1), comprising
an insulating body (41) which is of diffusion-open design, characterized
in that the heat insulating element (4) further comprises a fabric (42),
especially a fleece, which is of capillary-active design, and that the
fabric (42) is arranged and laminated on a surface of the insulating body
(41).
2. The heat insulating element according to claim 1, characterized in
that the fabric (42) comprises a capillarity for water with a capillary
rise of more than 15 cm, preferably more than 20 cm.
3. The heat insulating element according to claim 1, characterized in
that the fabric (42) is formed of glass fibers or plastic fibers.
4. (canceled)
5. The heat insulating element according to claim 1, characterized in
that the insulating body (41) has a .mu. value of .ltoreq.3, preferably a
.mu. value of .ltoreq.2.
6. The heat insulating element according to claim 1, characterized in
that the insulating body (41) is formed of mineral wool or natural
fibers, especially soft wood fibers.
7. A building construction with a separator between an inner side and an
outer side of a building (1), wherein the inner side corresponds to a
warm side of the building (1) and the outer side corresponds to a cold
side of the building (1), and with a plurality of heat insulating
elements (4) for an interior insulation, a facade insulation, or the like
at said building (1) further comprising an insulating body (41) which is
of diffusion-open design, characterized in that the heat insulating
element (4) further comprises a fabric (42) which is of capillary-active
design, and that the fabric (42) is arranged and laminated on a surface
of the insulating body (41).
8. The building construction according to claim 7, characterized in that
the separator is a wall element (3') and the heat insulating elements (4)
form an interior insulation, wherein the fabric (42) is arranged to face
the wall element (3').
9. The building construction according to claim 7, characterized in that
the separator is a wall element (3) and the heat insulating elements (4)
form a facade insulation, wherein the fabric (42) is arranged to face
away from the wall element (3) toward the outer side.
10. The building construction according to claim 7, characterized in that
the separator is a roof structure (2) and the heat insulating elements
(4) form a roof insulation, wherein the fabric (42) is arranged to face
away from the roof structure toward the outer side.
11. (canceled)
12. A method for avoiding moisture damage at a building (1) comprising a
separator such as a wall element (3; 3') or a roof structure (2) and
equipped with heat insulating elements (4) for an interior insulation, a
facade insulation, or the like at said building (1) further comprising an
insulating body (41) which is of diffusion-open design, wherein the
separator is arranged between an inner side and an outer side of a
building (1), wherein the inner side corresponds to a warm side of the
building (1) and the outer side corresponds to a cold side of the
building (1), wherein the method comprises the steps of: occurring of a
moisture accumulation in the region of the fabric (42), extensively
distributing the moisture due to the capillary-active property of the
fabric (42) for increasing the area of evaporation, guiding off the
moisture by evaporation and thus drying the area concerned of the fabric
(42).
13. The method according to claim 12, characterized in that the moisture
is guided off by means of diffusion through the diffusion-open insulating
body (41).
14. The method according to claim 12, characterized in that the moisture
is guided off by evaporation from the side of the fabric (42) which faces
away from the insulating body (41).
15. Use of a heat insulating element according to claim 1 for an interior
insulation, a facade insulation, a roof insulation, or the like at a
building (1).
Description
BACKGROUND OF THE INVENTION
[0001] The invention relates to a heat insulating element for an interior
insulation, a facade insulation, a roof insulation, or the like at a
building, comprising an insulating body which is of diffusion-open
design. The invention relates further to a building construction in
accordance with the preamble of claim 7, to a method for avoiding
moisture damage at a building in accordance with claim 12, and to the use
of a heat insulating element of this type in accordance with claim 15.
[0002] Nowadays, when constructing buildings, the application of a heat
insulation belongs to standard so as to avoid the loss of energy through
the shell of the building. Accordingly, roofs are regularly provided with
an insulating layer which may be disposed at the inside or else at the
outside. The same applies for the outer walls of the building which can,
as a rule, not enfold sufficient heat insulation from their intrinsic
structure. Usually, insulating layers are arranged here at the outside in
the kind of a heat insulation compound system. If this is not possible,
such as for instance in the case of buildings having listed facades, it
is, however, also known to insulate the wall elements at the inner side.
[0003] The walls and roof structures, however, basically have to be
protected from moisture penetration. Especially when diffusion-open
insulating materials such as mineral wool are used, it is important to
prevent the entry of moisture preferably right from the start. Among
experts, very precise requirements exist in the normative guidelines,
which regulate, for instance, the designing of the water vapor diffusion
resistances at the sides of a mineral wool insulation at a steep roof, so
that no damage may occur in the long run. In practice, suitable systems
for roof structures and/or facade designs have been developed in this
respect.
[0004] These normative requirements can, however, not deal with any case
of damage, for instance, at a sarking membrane of a steep roof. Then, the
entry of moisture in a roof structure, for example due to rain, can no
longer be prevented reliably.
[0005] While the problem of the entry of moisture from the outside at roof
structures and facades has traditionally been mastered very well, there
are, especially in the heating period, problems at the insulating layers
within the wall and/or the roof structure due to the forming of
condensation water. This is especially problematic in the case of an
interior insulation of the building. Here, the outer walls are not within
the thermal sheath, i.e. the insulating plane. If the interior is heated,
for instance, in the winter, a large temperature difference will appear
across the insulating plane. In this case, however, the wall element does
not absorb the temperature of the warm inner side, but is cooled through
at the outside air. Due to the warm, moist air impinging on the cool
outer wall, condensation water may be produced at this place between the
insulating plane and the outer wall, which may result in consequential
damage at the building. It is essential that this be avoided.
[0006] Condensation water is produced in relation with the temperature
profile in the building, for instance, an outer wall, and the saturated
vapor pressure at different temperatures. The amount of humidity to be
absorbed maximally by the air depends on the existing temperature. For
the water vapor diffusion through a building component the water vapor
pressure difference is the driving force. The water vapor pressure
depends on the temperature and the relative air humidity. With a constant
temperature the vapor pressure is a linear function of the relative air
humidity. If a temperature difference exists in addition, this results in
the appearance of a vapor diffusion stream as a rule from high to low
temperatures, even if the relative air humidity at warm temperatures,
i.e. at the inner side, related to the cold temperatures, i.e. at the
outer side, is identical or even lower. From a certain point on, the
difference of the water vapor concentration can no longer be borne by the
cooler air and precipitates as condensation water. If this area in which
liquid water is produced is within a building component, damage of the
building component may occur.
[0007] Among experts, numerous proposals have already existed for
eliminating moisture problems of this kind. In some proposals the
capillary-active effect of substances is used in order to guide
penetrated water and/or produced condensation water off the area
concerned, and to thus dry the corresponding area. Examples thereof
result from DE 101 46 174 A1, EP 1 657 496 A2, DE 10 2007 025 303 A1, DE
20 2009 008 493 U1, DE 10 2008 035 007 A1, EP 2 186 958 A2, DE 10 2011
113 287 A1, EP 2 666 625 A1, DE 10 2012 018 793 A1, DE 10 2012 219 988
A1, and EP 3 031 992 A1. In these cases the insulating layer itself is
designed to be capillary-active, or it is penetrated by capillary-active
elements. In the capillary-active areas the moisture is thus sucked in,
guided off the wall and/or the roof structure, and taken to an area where
the moisture may evaporate. EP 3 031 992 A1, for instance, uses such
capillary-active segments penetrating the insulating material, and a
wall-side coating to guide liquid by means of capillary guidance from the
one side to the other side of the insulating layer.
[0008] It has, however, turned out in practice that such systems work
insufficiently only. Specifically, it is by no means the case that the
capillary activity would be effective in one direction only, which is why
the moisture indeed distributes across the insulating layer, but then an
equilibrium is reached, so that a substantial share of moisture remains
in the critical area nevertheless.
[0009] Moreover, such capillary-active elements are complex and expensive
to produce. Their processing when being installed at the building
construction is also more difficult than with conventional systems.
[0010] It is therefore an object of the invention to provide an improved
heat insulating element for avoiding moisture damage at a building, by
means of which drying of the area concerned can be accelerated with
simple means if water, especially condensation water, accumulates.
Furthermore, it is an object of the invention to provide an appropriate
building construction in which moisture damage can be avoided more
reliably, and to provide an improved method for avoiding moisture damage
at a building.
[0011] In accordance with a first aspect of the present invention the
object is solved by a heat insulating element with the features of claim
1. It is characterized in particular in that the heat insulating element
further comprises a fabric, especially a fleece, of capillary-active
design, and that the fabric is arranged on a surface of the insulating
body.
[0012] The invention is based on the finding that the drying of water
penetrated in a building construction or accumulated therein can be
accelerated substantially if a distribution of the moisture on a larger
area is achieved by means of a capillary-active fabric. The water
distributes in the layer formed by the fabric and then dries at the
substantially larger surface. The evaporation of the water is moreover
supported substantially by the fact that the insulating body is at the
same time of diffusion-open design and thus permits the moisture to be
carried off.
[0013] The active principle can be explained illustratively by means of a
heat bridge in a building corner of an interior insulation. During the
winter period, condensation water may occur directly in the heat bridge
in the plane between the brickwork and the interior insulation. This
condensation water remains naturally in the building corner and takes a
long time to dry again since exactly in these corner regions a very small
surface is available for discharging the water vapor into the ambient
air. With the use of the capillary-active fabric in accordance with the
invention in the condensation plane, i.e. in the layer between the wall
and the interior insulation, accumulating condensation water is now
absorbed and distributed in correspondence with the capillary
transporting properties of the fabric. Thus, the area across which the
amount of condensation water may dry toward the inner face is increased.
This increase of the drying face thus results in substantially quicker
drying and hence in a long-term higher damage freedom of the building
construction.
[0014] The accelerated drying process may, however, also be used equally
if, due to damages to a sarking membrane of a steep roof, a facade or the
like, rain water, melt water, etc. penetrates into the building
construction. Here, too, the capillary-active design of the fabric causes
an immediate distribution of the moisture to a larger area and allows for
quick drying thereof.
[0015] Moreover, this can be done with a particularly low constructional
effort. The arrangement and/or application of fabrics on an insulating
body is possible with approved means in production-technical respect. It
is not necessary to penetrate the insulating body with a capillary-active
element. In accordance with the invention the fabric is merely disposed
on a large surface of the insulating body.
[0016] By means of the heat insulating element in accordance with the
invention it is thus possible to achieve in a very simple and quick
manner a suitable building construction for avoiding moisture damage.
Moreover, the capillary-active fabric protects the building construction
in a reliable manner in the long term.
[0017] Apart from the low effort for providing the heat insulating element
in accordance with the invention, such construction of a building can be
implemented in a particularly cost-efficient and time-saving manner. At
the same time, this does not require any additional processing steps or
measures that would be unusual for the operator.
[0018] From practice, insulating elements with a fabric lamination have
indeed become known, which are, for instance, used for interior
insulation. The fabric lamination, however, is available always toward
the side of the interior and serves as a trickle protection for the
mineral wool material or the like. Therefore, it cannot contribute to the
avoiding of condensation water accumulation and to the elimination
thereof.
[0019] Advantageous further developments of the heat insulating element in
accordance with the invention are the subject matter of the dependent
claims 2 to 6.
[0020] It has turned out to be advantageous if the fabric comprises a
capillarity for water with a capillary rise of more than 15 cm. It
applies basically that the distribution of the condensation water or the
like takes place the more efficiently the larger the capillarity of the
fabric is. With a capillary rise of more than 15 cm very good drying
results could already be achieved in practical tests. Preferably, the
capillary rise for water is more than 20 cm, which results in an even
larger and better distribution of the moisture and hence even better
evaporation thereof.
[0021] It is per se irrelevant of which material the fabric is made. It
merely has to have a structure which admits capillary activity. However,
fabrics of glass fibers or plastic fibers have turned out to be
particularly suited for the common use at a building. They are of
sufficiently diffusion-open, homogeneous, and robust design for the usual
purpose of application.
[0022] It is of further advantage if the fabric is laminated on the
insulating body. Then, it can be connected reliably with the insulating
body with an approved method and need not be handled separately.
[0023] The diffusion openness of the insulating body is of further
importance for evaporation. It has turned out to be advantageous if it
has a .mu. value of .ltoreq.3. With this water vapor diffusion resistance
number the resistance is expressed with which a body counteracts the
diffusion of water vapor. The smaller the value, the less resistance is
thus offered to the water vapor diffusion, and the better can the
moisture be guided off by the insulating body. Preferably, the insulating
body has a .mu. value of .ltoreq.2, which corresponds to an even better
diffusion openness.
[0024] If the insulating body is made of mineral wool, a material is used
which has been very approved in insulation technology. Mineral wool has
good insulating values, is flame-retardant, and diffusion-open.
Alternatively, natural fibers such as in particular soft wood fibers may
also be used for the insulating body, which is, for ecologic reasons,
also frequently desired in building construction. These materials are
also of diffusion-open design.
[0025] In accordance with a further aspect of the present invention,
according to claim 7 a building construction is provided with a separator
between an inner side and an outer side of a building, wherein the inner
side corresponds to a warm side of the building and the outer side
corresponds to a cold side of the building, and with a plurality of heat
insulating elements which each comprise an insulating body of
diffusion-open design. This building construction is characterized in
that a fabric which is of capillary-active design is arranged on a
surface of the insulating body, and that the fabric is arranged to face
the cold side of the building.
[0026] In the case of a building construction of such design it is thus
reliably possible to guide moisture off the construction. Due to the
capillary-active fabric a large-face distribution of the moisture is
achieved, which promotes the evaporation thereof.
[0027] Due to the fact that the fabric is arranged to face the cold side
of the building, it is moreover available at a position at which the
accumulation of moisture and/or the entry of moisture is to be expected.
Thus, this measure is effective exactly in the region in which the demand
is highest.
[0028] In this manner, i.e. by the increased drying potential, it is
advantageously possible to avoid moisture damage at the building
construction in a very reliable and permanent manner. At the same time,
this may be implemented with little provision effort, processing
requirements, and hence also costs.
[0029] Advantageous further developments of the building construction in
accordance with the invention are the subject matter of the dependent
claims 8 to 11.
[0030] Thus, the separator may be a wall element, and the heat insulating
elements may form an interior insulation, wherein the fabric is arranged
to face the wall element. Then, the classical problem of an interior
insulation exists, which may lead to condensation water between the
insulating layer and the wall. In this case, the fabric is thus available
between the heat insulating elements and the wall element and absorbs
possible water in this place and/or distributes same to a larger face.
The moisture may then diffuse through the diffusion-open insulating
bodies of the heat insulating elements and be dissipated to the interior
of the building. Moisture damage such as the formation of mold or the
like can thus be avoided in a particularly reliable manner.
[0031] Alternatively, it is also possible that the separator is a wall
element and the heat insulating elements form a facade insulation,
wherein the fabric is arranged to face away from the wall element toward
the outer side. Then, moisture occurring at this place may, also in this
embodiment, be distributed reliably to a larger face and be dissipated
above all to the outside, e.g. into a plaster layer. A temporary
accommodation of the moisture in the diffusion-open insulating bodies of
the heat insulating elements is also possible, so that a water congestion
at this place may be avoided. Thus, moisture damage at the building can
be avoided reliably.
[0032] In a further alternative it is also possible that the separator is
a roof structure and the heat insulating elements form a roof insulation,
wherein the fabric is arranged to face away from the roof structure
toward the outer side. Like in the foregoing variant it is thus possible
to avoid the accumulation of moisture at one place by the moisture being
distributed across a larger area due to the capillary effect of the
fabric. Evaporation of the moisture and drying of the building
construction in this area is thus possible in a particularly reliable
manner.
[0033] Moreover, the heat insulating element may also be further developed
in correspondence with the features of claims 2 to 6, so that the
building construction takes direct advantage of the effects of the heat
insulating element in accordance with the invention.
[0034] In accordance with yet another aspect of the present invention a
method for avoiding moisture damage at a building is provided in
accordance with claim 12. The building comprises a separator such as a
wall element or a roof structure and is equipped with heat insulating
elements. The separator is arranged between an inner side and an outer
side of the building, wherein the inner side corresponds to a warm side
of the building and the outer side corresponds to a cold side of the
building. The heat insulating elements each comprise an insulating body
which is of diffusion-open design and comprises a fabric on a surface,
wherein the fabric is of capillary-active design, and wherein the fabric
is arranged to face the cold side of the building. The method in
accordance with the invention comprises the steps of: occurring of a
moisture accumulation in the area of the fabric, extensively distributing
the moisture due to the capillary-active properties of the fabric for
increasing the area of evaporation, guiding off the moisture by
evaporation and thus drying the area concerned of the fabric.
[0035] With the method in accordance with the invention it is possible to
achieve the above-explained advantages with respect to the heat
insulating element according to claim 1 and/or the building construction
according to claim 7 in an analogous way. Specifically, moisture damage
at a building can thus be avoided reliably and permanently in a simple
and cost-efficient manner.
[0036] Advantageous further developments of the method in accordance with
the invention are the subject matter of the dependent claims 13 and 14.
[0037] Thus, the moisture may be guided off by means of diffusion through
the diffusion-open insulating body. This is expedient above all in the
case of interior insulation since the wall element here acts as a kind of
barrier body and the air at the warm inner side is moreover better suited
to absorb moisture.
[0038] Alternatively it is also possible that the moisture is guided off
by evaporation from the side of the fabric which faces away from the
insulating body. This is expedient above all with insulating layers
arranged at the outer side. Then, reliable removal of the moisture may be
achieved by the larger evaporation face of the capillary-active fabric.
[0039] In accordance with yet another aspect of the invention the use of a
heat insulating element according to the invention is claimed in
accordance with claim 15 for an interior insulation, a facade insulation,
a roof insulation, or the like at a building.
[0040] A heat insulating element used in this manner is of advantage for
all these different insulation variants at a building in that moisture
damage is avoided in a particularly reliable manner. Moreover, with the
use of the heat insulating element in accordance with the invention a
cost-efficient measure may be chosen for this purpose.
BRIEF DESCRIPTION OF THE DRAWINGS
[0041] In the following, the invention will be explained in detail in
embodiments by means of the Figures of the drawing. There show:
[0042] FIG. 1 a section through a roof structure of a building which is
designed in accordance with the invention;
[0043] FIG. 2 a section through a roof structure of a building which is
designed conventionally as compared to FIG. 1;
[0044] FIG. 3 a section through a wall element with exterior insulation
designed in accordance with the invention;
[0045] FIG. 4 a section through a wall element in accordance with the
invention pursuant to a further embodiment with an interior insulation;
[0046] FIG. 5 a perspective view of a heat insulating element in
accordance with the invention with accumulated moisture; and
[0047] FIG. 6 a diagram for comparing the drying period of heat insulating
elements with and without capillary-active fabric.
DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION
[0048] FIG. 1 illustrates a building 1 with a roof structure 2 designed in
accordance with the invention. For comparison, a conventional roof
structure D is illustrated in FIG. 2. FIGS. 3 and 4 illustrate wall
elements 3 and 3' which are designed in accordance with the invention.
[0049] Pursuant to the sectional illustration in FIG. 1 the roof structure
2 comprises a roof covering 21 and a sub construction 22 therefor.
Therebelow is positioned a sarking membrane 23 which covers an over
rafter insulation formed of heat insulating elements 4. At the outer side
the over rafter insulation rests on rafters 24 between which a between
rafter insulation 25 is disposed. A vapor barrier 26 and a sheathing 27
form the inner-side termination.
[0050] Each heat insulating element 4 comprises an insulating body 41 of
mineral wool and a capillary-active fabric, in particular a fleece 42 of
glass fibers. The fleece 42 is laminated on the insulating body 41 and is
available at the outer side in the direction of the sarking membrane 23.
[0051] In the illustrated embodiment the sarking membrane 23 comprises a
defect S through which moisture may penetrate onto the over rafter
insulation.
[0052] For comparison, FIG. 2 illustrates the conventional roof structure
D which differs from the structure of the building construction pursuant
to FIG. 1 only by the fact that, instead of the heat insulating element
4, a conventional, non-laminated mineral wool plate is disposed as an
element of the over rafter insulation. Also in the arrangement pursuant
to FIG. 2 a defect S is available in the sarking membrane.
[0053] As is shown in the illustration in FIG. 2, moisture enters through
the defect S into the mineral wool of the over rafter insulation and
damages the structure thereof. The moisture distributes conventionally in
correspondence with the usual behavior of water substantially in a
drop-shaped manner and is accumulated in the region of the defect S.
Therefore, the water can dry only very slowly.
[0054] In the roof structure 2 in accordance with the invention pursuant
to the illustration in FIG. 1 the insulating body 41 is, on the contrary,
laminated with the fleece 42 which is of capillary-active design. The
water entered through the defect S distributes along the fleece 42 and
covers accordingly a larger area than in the state of the art. No water
accumulation as it is known from the state of the art will occur. For
this reason, the moisture dries from the heat insulating element 4
substantially more quickly and diffuses on a large face to the outside
through the sarking membrane 23.
[0055] FIG. 3 illustrates a section through the wall element 3 of the
building 1 which is provided with an exterior insulation. It comprises at
the inner side a plaster layer 31 which is applied on a supporting wall
32. At the outer side there follows the exterior insulation of heat
insulating elements 4. The insulating body 41 rests on the wall 32 while
the capillary-active fleece 42 laminated thereon is arranged on the side
of the insulating body 41 which faces away from the wall 32. On the
fleece 42, finally, an exterior plaster 33 is arranged.
[0056] The illustration in FIG. 3 further illustrates by means of a line A
the temperature profile in the wall element 3 during the heating period
across the wall thickness. With the line B the dew point in the wall
element 3 is further illustrated. Since the insulating plane of this
exterior wall insulation is available outside of the wall 32, no
accumulation of condensation water will occur here as a rule.
[0057] It is, however, possible that the exterior plaster 33 is damaged
due to external influences or the like and that moisture may thus
penetrate into the wall element 3. There, however, this moisture
encounters first of all the capillary-active fleece 42 which distributes
the moisture directly to a larger face and thus favors the drying
thereof. Since the moisture entry typically takes place here and there
and only in the case of rain showers, for instance, the time of rain
breaks will frequently suffice to achieve a uniform dissipation of
moisture across a larger area into the exterior plaster and thus to the
environment. Damage of the insulating body 41 can thus be avoided
reliably.
[0058] FIG. 4 shows the wall element 3' provided with an interior
insulation. Here, too, a plaster layer 31' is available at the inner
side, which is, however, followed by the interior insulation formed of
heat insulating elements 4. The insulating body 41 is positioned adjacent
to the plaster layer 31' while the capillary-active fleece 42 is arranged
at the side of the insulating body 41 which faces a wall 32'. At the
outer side the wall structure is terminated by an exterior plaster 33'.
[0059] Also in this illustration is the temperature profile through the
wall element 3' shown by means of a line A'. Likewise, the dew point is
plotted by means of a line B'. As is shown in the illustration, the
temperature drops strongly within the interior insulation while it
experiences only little cooling in the wall 32'. The wall 32' is
available outside of the insulating plane, which results in that
condensation water may accumulate at the boundary surface between the
wall 32' and the fleece 42 especially during the heating period.
Conventionally, the condensation water would accumulate in this area
especially at corners and places of joint, and would lead to mold
formation or the like.
[0060] By the capillary-active fleece 42 possibly existing moisture is,
however, distributed across a large face, so that it can dry easily and
quickly. This takes place through the diffusion-open insulating body 41
via the plaster layer 31' into the interior of the building 1.
[0061] FIG. 5 illustrates a perspective view of a portion of the heat
insulating element 4. In the foreground, the capillary-active fleece 42
is illustrated, which is only laminated on a large face on the insulating
body 41. As a fleece 42 the product known under the brand name EVO 170 is
used.
[0062] In the illustrated example the heat insulating element 4 rests
against a corner region, for instance, in a window reveal where
condensation water T accumulates. The water accumulates directly in the
corner, but is then sucked in by the capillary-active fleece 42 and
distributed across a larger face F. From there it may dry quickly and may
be discharged through the diffusion-open insulating body 41.
[0063] Laboratory tests concerning the drying behavior in the corner
region of a window reveal as a "worst case" scenario have shown that in
this manner a quite substantial acceleration of the drying process may be
achieved. FIG. 6 illustrates in a diagram the drying period in hours,
wherein a sample with a fleece 42 is plotted with the line M and a sample
without the fleece 42 with the line O. The drying period was ascertained
by determining the change in mass of the sample since this proceeding
appeared suitable to be able to reliably ascertain the remaining moisture
content of the sample. The qualitative difference between the sample with
the fleece 42 and the sample without the fleece 42 can be recognized
directly.
[0064] The success of the distribution of moisture on a large face depends
predominantly on the capillarity of the fleece 42. The suction distance
and the suction velocity of the fleece 42 play an important role here.
These parameters depend less on the material of the fleece, but rather on
the weaving technique and/or the geometry of the fibers which cooperate
here.
[0065] Capillarity describes the rising or sucking process of a liquid
when getting into contact with narrow tubes (capillaries) or small
cavities. The liquid will in this case distribute to a larger face and
rise even against gravity. This effect occurs due to the molecular forces
in the liquid and the surface tension involved therewith. In the instant
application this liquid is as a rule water which is characterized by a
large surface tension. Two factors play a quite substantial role here,
namely cohesion and adhesion.
[0066] Cohesion is the "cohering force" of the molecules in a body. In a
liquid the cohesive forces are so small that the molecules may move
within the liquid. Adhesion is the "attraction force" between the
molecules of two different substances.
[0067] If the liquid meets a solid surface and the adhesive forces between
this surface and the liquid are stronger than the cohesive forces of the
liquid, the liquid will attempt to wet the surface. In this process the
molecules of the liquid are attracted by the adhesive forces by the
surface of the solid body. Due to the cohesive forces, molecules which
were attracted by the surface will drag along the remaining molecules.
Thus, a meniscus will form at the contact face, i.e. the liquid will rise
at the wall.
[0068] The capillary rise of a liquid may be calculated by means of the
following equation:
h=2.sigma. cos .theta./.rho.gr
wherein: [0069] h=capillary rise of the liquid [0070] .sigma.=surface
tension [0071] .theta.=contact angle [0072] .rho.=density of the liquid
[0073] g=gravitational acceleration [0074] r=radius of the capillaries
[0075] At 20.degree. C. the surface tension .sigma. for water is 72.75
mN/m. Apart from this the density of water and the acceleration are also
constant. If one assumes a contact angle of 0.degree., a value of 1 will
result for the factor cos .theta.. Thus, the radius of the capillaries r
remains as the only variable in this equation.
[0076] In the fleece 42 this factor r is determined by the cavities and
the weaving structure, from which appropriate capillary rises of water
can as a rule be determined by experiments for different fleeces. In the
instant embodiments fleeces with a capillarity for water with a capillary
rise of more than 15 cm have turned out suitable. If a higher value is
chosen, the effect of distribution of the liquid on a larger face is the
more distinct.
[0077] In addition to the embodiments explained, the invention allows for
further design approaches.
[0078] Thus, it is not mandatorily necessary that the capillary rise of
the fleece 42 is more than 15 cm. For some applications a lower capillary
rise of e.g. 10 cm may also be sufficient.
[0079] Furthermore, the fleece 42 need not be made of glass fibers.
Instead, plastic fibers or mixtures of different kinds of fibers may also
be used. Also the kind of weaving of the fleece 42 may be arbitrary per
se as long as it is of capillary-active design. Thus, the fleece 42 may,
for instance, also be a fleece EVO 130, an Ortmann fleece, or any other
suitable capillary-active fleece.
[0080] Furthermore, it is not necessary that the fleece 42 is laminated on
the insulating body 41. It may also be connected therewith by a needling
process or simply be arranged loosely next to it.
[0081] The insulating body 41 comprises a water vapor diffusion resistance
.mu. of .ltoreq.3. In order to improve the diffusion capacity, a lower
.mu. value may, however, also be chosen, for instance, .mu. equal to 2.
[0082] In the illustrated embodiment the insulating body 41 is formed of
mineral wool. Instead, other types of fiber and especially natural fibers
such as, for instance, soft wood fibers or the like, may also be used.
Mixtures of such fibers are also possible.
* * * * *