Thermal insulating element for fire protection of building equipment and fire-resistant ventilation duct system

Abstract

Main subject of the invention is a thermal insulating element (1) for fire protection of building equipment and industrial installations, the element (1) being in the form of a mineral wool wired mat, comprising a mineral wool mat (3) covered with a wire mesh (4) and an aluminum foil (2), especially as part of an intermediate layer (5) comprising the aluminum foil (2), on a major surface of the mat (3). To increase the fire resistance of the thermal insulating element (1) the aluminum foil (2) and / or the intermediate layer (5) as such is perforated.

Description

[0001] Thermal insulating element for fire protection of building equipment and fire-resistant ventilation duct system

[0002] Main subject of the invention is a thermal insulating element for fire protection of building equipment and industrial installations, the element being in the form of a mineral wool wired mat covered with a wire mesh and an aluminum foil, especially as part of an intermediate layer comprising the aluminum foil on a major surface of the mat. Furthermore, main subject of the invention is a fire-resistant ventilation duct system comprising a sheet metal air duct and a layer of at least one thermal insulating element for fire protection, the element being a mineral wool wired mat as described above.

[0003] Fire protection of building equipment, such as ventilation ducts, are required to have a fire resistance corresponding to the fire compartments the ventilation ducts pass through in a building. Fire insulated ducts are tested according to the European standard EN 1366- 1 :2014+A1 :2020. Ventilation duct systems can run in vertical or horizontal direction in the building and according to the before mentioned standard the system has to be tested both for vertical and horizontal ducts, as well as for internal and external fire exposure. An internal fire exposure on ventilation systems can occur due to several incoming and outgoing valves in the same fire compartment.

[0004] Respective mineral wool thermal insulating elements or mineral wool thermal insulation products for fire protection of building equipment and industrial installations are stipulated and specified according to European standard EN 14303:2015 "Thermal insulation products for building equipment and industrial installations - Factory made mineral wool (MW) products - Specification”.

[0005] The term mineral wool is used to describe insulation made from minerals. This includes stone, silica and other materials that are extremely resistant to heat. The raw materials are heated to a high temperature and, once molten, spun into fibers. These fibers are then formed into finished insulation products, such as slabs, mats, rolls, pipe sections etc.

[0006] Two of the most common types of mineral wool are stone wool, made from volcanic rock, and glass wool, which is made from silica or glass cullet. Glass wool is also referred to as glass fiber. From the prior art different products are well known to be arranged outside a ventilation duct such as “CONLIT Fire Board” or “CONLIT Fire Mat”, both products commercially available from ROCKWOOL A / S. The CONLIT Fire Board is made of non-combustible, moist and water repellent stone wool and designed to provide maximum fire protection. The front of the product is covered with a black reinforced aluminum foil. The back of the product is uncovered. These boards are used for fire protection of rectangular ventilation ducts and are tested and approved for fire classes EI30 to El 120.

[0007] CONLIT Fire Mat is made from non-combustible, moist and water repellent stone wool and specifically designed to provide maximum fire protection. The CONLIT Fire Mat is available inter alia in fire class EI30 and having a front being finished with a black reinforced aluminum foil and a galvanized wire mesh or wire netting. CONLIT Fire Mat is preferably used for fire protection of ventilation ducts with circular cross section. Nevertheless, these mats can also be used with rectangular and rounded ventilation ducts.

[0008] Although these products have proofed its worth in practice there seem to be some requirements for increased fire protection.

[0009] Furthermore, WO 93 / 21061 discloses a mineral wool fabric or mat with wire mesh coated on, preferably one side thereof, particularly for paneling walls and / or ceilings of ships and boats. Under the aspect of cost efficiency and weight reduction this well-known mineral wool fabric or mat is characterized in that a non-flammable protective layer is provided between the fabric or mat and the wire mesh. The protective layer is made of a glass fabric. With respect to fire protection, a glass fabric has several drawbacks and is of disadvantage.

[0010] These surface layers are difficult to dedust and clean, and the market prefers or even demands surfaces in the form of a reinforced aluminum foil which is easy to dedust and clean.

[0011] The problem associated with the prior art relates to the fire resistance testing for service installations according to European standard EN 1366-1 :2014+A1 :2020, specifically when testing for fire class EI60 and better. Testing of wired mats finished with a reinforced aluminum foil and a wire mesh revealed a problem as indicated above and as will be described in more detail here below.

[0012] It appears that by a fire exposure over 60 minutes or above the pyrolytic gases from the organic content of the mineral wool cannot escape freely through the aluminum facing of the product, but only through small holes made by a sewing machine used for fixing the wire mesh and any such facing on a major surface of a respective mineral wool wired mat. Oxygen can penetrate through the holes into the mat and can get into contact with the combustible pyrolytic gases inside the mat. As caused by the fire, the temperature inside the mat raises and a smoldering combustion can take place which might lead to sintering of the fibers. By this the temperature on the unexposed surface is increasing over the limited temperatures that is given in the test standard (EN 1366-1). The most important organic content in the mat is an organic binder.

[0013] Another aspect is that using a layer different from a glass fabric has the advantage that it is easier to dedust and clean the outside surface of the mat as it is necessary in certain rooms like professional kitchens, certain areas in hospitals or other buildings where clean top surfaces are necessary also in the areas of the ventilation duct systems. Cleaning the layer of glass fabric results in a lot of dust from fibers being loosen from the surface of the fabric.

[0014] To use an aluminum foil instead of a glass fabric solves the problem of cleaning the top surfaces but causes the problem described before with respect to the fire resistance of the insulation elements provided outside on the ventilation ducts.

[0015] It is therefore an object of the invention to provide a fire-resistant thermal insulating element for the protection of building equipment and industrial installations which can be easily cleaned at its outer surfaces and which avoids the problems associated with the prior art as described before.

[0016] Furthermore, it is an object to provide a fire-resistant ventilation duct system fulfilling requirements of at least EI30 according to EN 1366-1 :2014+A1 :2020, preferably of at least EI60, more preferably of EI90, even El 120.

[0017] The object with respect to the thermal insulating element is advantageously accomplished in that the aluminum foil as such is perforated, e. g. micro-perforated. The aluminum foil can be part of an intermediate layer being arranged between the mineral wool mat and the wire mesh. In this embodiment the intermediate layer as such is perforated, e. g. microperforated. With respect to the fire-resistant ventilation duct system the object is advantageously accomplished by providing an aluminum foil, especially as part of an intermediate layer comprising the perforated aluminum foil, on a major surface of the mat. The aluminum foil as such is perforated, e. g. micro-perforated, which means that this aluminum foil already is provided with small holes before fixing it to the thermal insulating element, respectively to the mineral wool wired mat. In case the aluminum foil is part of the intermediate layer, the intermediate layer as such is perforated, which means that all parts of the layer are perforated before connecting the layer to the surface of the mat or product made from mineral wool.

[0018] With respect to the present invention, when referring to a thermal insulating element for fire protection of building equipment and industrial installations, it is meant to in particular cover mineral wool products as specified further above. More specifically, a mineral wool wired mat is addressed. Such wired mats are typically covered with a wire mesh and optionally an intermediate layer or facing.

[0019] The base mineral wool mat or product according to the invention comprises a thickness typically in the range of 60 mm to 120 mm, preferably 80 mm to 100 mm, and a density in the range of 60 kg / m3to 100 kg / m3, preferably 70 kg / m3to 80 kg / m3.

[0020] The intermediate layer of the present invention typically will be a composite element with at least a perforated aluminum foil, a reinforcement layer of bi-directional fiberglass and a heat seal co-polymer as a film. The intermediate layer with the perforated aluminum foil is applied to the base mineral wool mat by a sewing process with which the layer is fixed to the mat using a wire and / or a thread running through the layer and the mat. Such layer with a perforated aluminum foil and as used herein, will typically be a reinforced aluminum foil in the form of a laminate comprising a base polymer film, a reinforcement, an aluminum foil and optionally a coating. The parts of the intermediate layer as such are perforated, too.

[0021] An example for such a layer comprises the base polymer film having a thickness of 10 microns to 15 microns, preferably 12,7 microns and being perforated and the perforated aluminum foil having a thickness of 15 microns to 18 microns, preferably of 16,5 microns. The reinforcement being part of the layer is a bi-directional fiberglass with 20 threads on 100 mm length in machine direction and transverse to the machine direction building up openings between the threads of approx. 5 mm length and 5 mm width.

[0022] The wire mesh and the ‘wire for fixing the mesh to the mineral wool mat or product will typically be made of steel, preferably galvanized steel, or stainless steel.

[0023] By replacing an aluminum foil with a micro-perforated aluminum foil or a micro-perforated intermediate layer comprising the micro perforated aluminum foil, the smoldering combustion can be avoided and a result close to or comparable to an unfaced mat can be obtained. Moreover, the outside surface of the thermal insulating element is provided and protected by a layer being easy to dedust and to clean and which makes it possible to use such thermal insulating elements for fire protection of building equipment and industrial installations in areas of buildings requiring high degree of purification as for example in canteen kitchens, hospitals or the like. The fire resistance can be prolonged compared to a non-perforated foil.

[0024] According to a feature of the invention, the perforated aluminum foil or the perforated intermediate layer has a perforation patern with 6 holes per cm2to 60 holes per cm2, preferably with 9 holes per cm2to 50 holes per cm2. Such a pattern has the advantage that on the one hand most of the surface of the foil or layer is closed and can easily be dedusted and cleaned and the specific number of holes per cm2allows to remove pyrolytic gases resulting from the organic content of the mineral wool through the facing of the product so that the increase of temperature inside the product can be limited avoiding sintering of the fibers.

[0025] Preferably, the holes have a diameter between 0,1 mm and 0,5 mm, further preferably of 0,2 mm. These diameters assure especially in connection with the specific number of holes per cm2the reduction of the temperature inside the product. A higher number of holes per cm2allows to reduce the diameter of the holes which is of advantage with respect to the cleanability of the surface of the insulating element. On the other hand, less holes provide surfaces with larger closed areas which also allows an easy cleaning of the insulation element surrounding the duct without the problem of a high ingress of fluid into the mineral wool mat or board.

[0026] Preferably, the aluminum foil has an outer surface being provided with a coating preferably made of a lacquer. Preferably, a blackened aluminum foil is used.

[0027] According to a further feature of the invention the wire mesh is connected to the mat by sewing with a thin wire and / or a thread. If a thread is used the thread should be made fire resistant for example by using threads made of ceramic fibers being heat resistant up to 1973 K .

[0028] Preferably, the aluminum foil or the intermediate layer comprising the aluminum foil and the wire mesh are fixed to the mat by the same thin wire and / or thread. By using the same thin wire and / or thread the production of the thermal insulating element can be done within one sewing step.

[0029] It has been found of advantage to use a coating being applied to the aluminum foil or the intermediate layer comprising the aluminum foil with a surface weight between 9,0 g / m2and 11 ,4 g / m2. Furthermore, the aluminum foil to be used has a thickness between 15 microns and 20 microns, preferably of 16,5 microns.

[0030] Finally with respect to the thermal insulating element it is a further feature of the invention that the holes of the patern are arranged in a regular patern with identical distances to each other in the machine direction of the foil or intermediate layer and transverse to it. This allows to discharge possible pyrolytic gases from inside of the mineral wool element via the whole surface independently from an allocation of the organic content, especially a binder content in the mineral wool mat or product.

[0031] The advantages of the invention can also be achieved in that the intermediate layer is replaced by an aluminum foil being perforated. The before described advantages of the features of the invention with respect to the thermal insulating element are also valid with respect to the fire-resistant ventilation duct system according to the invention.

[0032] Samples of the thermal insulating element according to the present invention have been tested for their performance when exposed to fire and for indicative purposes.

[0033] It is possible to test specimens in large-scale tests being costly but relevant for approval of the properties of the specimen with respect to their fire resistance. However, it is possible and for cost reasons preferable to use small-scale chamber tests according to former German standard DIN 4102-8 which are performed in particular for product development and routine control, to determine fire protection properties. Small-scale chamber tests are of advantage, as being a quick and affordable testing method, whereby the results can be correlated to those of the large-scale tests. The element to be tested is exposed on one surface with the temperature curve according to a test model. Regulations and construction are defined by the specific standard e. g. described in ISO 834 or EN 1363-1. The temperature increase over time is measured at the surface opposite to the surface being exposed to the temperature curve. To comply with the classification at defined intervals of usually 30, 60, 90 and 120 minutes, the average temperature increase of a number of metering points may not exceed typically 140 K and at no single metering point the temperature increase may typically exceed 180 K. Otherwise, fire resistance grading is not achieved. The small-scale chamber tests are operated in an electric heated furnace as described herein later.

[0034] Further features or advantages of the invention will be described herein after with respect to the drawing. In the drawing shows:

[0035] Fig. 1 a thermal insulating element for the protection of building equipment and industrial installations in a perspective view;

[0036] Fig. 2 the element according to fig. 1 in a section view along the line ll-ll of fig. 1 ;

[0037] Fig. 3 a first embodiment of the element according to fig. 1 in a plan view on the noncovered surface after 66 minutes of fire exposure;

[0038] Fig. 4 a second embodiment of the element according to fig. 1 in a plan view on the noncovered surface after 66 minutes of fire exposure;

[0039] Fig. 5 a third embodiment of the element according to fig. 1 in a plan view on the noncovered surface after 66 minutes of fire exposure and

[0040] Fig. 6 an element according to the prior art in a plan view on the non-covered surface after 66 minutes of fire exposure.

[0041] Fig. 1 shows a thermal insulating element 1 for fire protection of building equipment and industrial installations, especially of fire-resistant ventilation duct systems with at least one ventilation duct (not shown). The element 1 has the form of a mineral wool wired mat, comprising a mineral wool mat 3 covered with a wire mesh 4 and an intermediate layer 5 in the form of a composite element with an aluminum foil 2, a reinforcement layer 10 of bi- directional fiberglass and a heat seal co-polymer film 11 , the layer 5 being arranged on one major surface of the mat 3. The intermediate layer 5, namely the composite element with the aluminum foil 2 as such is perforated and has several small holes 6 penetrating the layer 5 in a direction rectangular to a major surface of layer 5.

[0042] The intermediate layer 5 with the perforated aluminum foil 2 has a perforation pattern with 50 holes per cm2whereby the holes 6 have a diameter of 0,2 mm, and whereby the holes 6 of the patern are arranged in a regular patern with identical distances to each other in the machine direction of layer 5 and transverse to it.

[0043] Furthermore, the layer 5 with the aluminum foil 2 has an outer surface 7 being provided with a coating 9, namely a black lacquer. The coating 9 applied to the aluminum foil has a surface weight of 10 g / m2.

[0044] Moreover, the perforated aluminum foil 2 has a thickness of 16,5 microns.

[0045] It can be seen from fig. 2 that the wire mesh 4 is connected to the mat 3 of mineral wool by thin wires 8 running through the layer 5 and the mat 3 whereby the wires 8 are provided to the thermal insulating element 1 by sewing.

[0046] The thermal insulating element 1 for fire protection of building equipment and industrial installations is provided as a mineral wool wired mat 3. The mat 3 can be delivered as a coil or winded roll and might be applied to rectangular, circular or rounded ventilation ducts in the known manner.

[0047] Fig. 3 shows a first example of a thermal insulating element 1 after 66 minutes of fire exposure to a surface 12 being arranged opposite the surface 7 with the layer 5 and the wire mesh 4. The aluminum foil 2 being part of the layer 5 is equipped with 50 holes 6 per cm2each hole 6 having a diameter of 0,2 mm. The exposed surface is still fibrous and no signs of sintering inside the mineral wool mat 3 can be detected. The holes provided by the stitching of the wire mesh 4 are not visible.

[0048] As a first example a thermal insulating element 1 with a nominal thickness of 70 mm and with a nominal density of 80 kg / m3has been used. The temperature increase after 60 minutes has been measured with 103 K in average at four different areas on the surface 12 with 4 type K thermocouples.

[0049] Fig. 4 shows an example of a thermal insulating element 1 comparable to the element 1 of fig. 3 but with 10 holes 6 per cm2each hole 6 having a diameter of 0,2 mm. After 66 minutes of fire exposure to the surface 12 the exposed surface 12 is still fibrous and no signs of sintering inside the mineral wool mat 3 can be detected but the holes provided by the stitching of the wire mesh 4 are slightly visible.

[0050] As a second example a thermal insulating element 1 with a nominal thickness of 70 mm and with a nominal density of 80 kg / m3has been used. The temperature increase after 60 minutes has been measured with 95 K in average at four different areas on the surface 12 with 4 type K thermocouples.

[0051] Fig. 5 shows a further example of a thermal insulating element 1 comparable to the element 1 of figures 3 and 4 but with 2,5 holes 6 per cm2each hole 6 having a diameter of 0,2 mm. After 66 minutes of fire exposure to the surface 12 the exposed surface 12 is slightly sintered. The sintering inside is more intensive near the holes provided by the stitching of the wire mesh 4 to the mineral wool mat 3. The sintering is even more severe and deeper in the thermal insulating element 1 compared to the examples of figure 3 and 4.

[0052] As a third example a thermal insulating element 1 with a nominal thickness of 70 mm and with a nominal density of 80 kg / m3has been used. The temperature increase after 60 minutes has been measured with 96 K in average at four different areas on the surface 12 with 4 type K thermocouples.

[0053] Just for a comparison fig. 6 shows a thermal insulating element 1 according to the prior art which means with an aluminum foil with no perforation on the surface 7. The surface 12 being exposed to a fire for 66 minutes is heavily sintered with a large amount of mineral wool being burnt and no more present. The dark color in fig. 6 indicates an incomplete combustion of the mineral wool.

[0054] As an example of a thermal insulating element 1 according to the prior art an element 1 with a nominal thickness of 80 mm and with a nominal density of 80 kg / m3has been used. The temperature increase after 60 minutes has been measured with 109 K in average at four different areas on the surface 12 with 4 type K thermocouples. All the testing has been conducted as small-scale chamber test horizontally on an electric heated furnace, with heat exposure from below, applied for a minimum of 66 minutes according to a standard time-temperature curve specified in ISO 834-1 and EN 1363-1. The furnace has an opening of 500 mm length and 500 mm width, Each example of an element 1 is cut with outer dimensions of approximately 595 x 595 mm as to fit in a metal frame placed above an opening of the furnace. The metal frame has a length and a width of 595 mm, each. At a bottom of the metal frame a galvanized steel plate with a thickness of 1 mm is placed matching with the inner dimensions of the metal frame. The material used is identical or at least very similar to the material used for ventilation ducts. Each example of the element has been secured to the metal frame by four welded pins running through the mineral wool and washers being arranged on the surface 7 of the element 1 . Therefore, the fire tests are performed simulating the upper face of a ventilation duct.

[0055] Reference list

[0056] 1 thermal insulating element

[0057] 2 aluminum foil

[0058] 3 mineral wool mat 4 wire mesh

[0059] 5 layer

[0060] 6 hole

[0061] 7 outer surface

[0062] 8 wire 9 coating

[0063] 10 reinforcement

[0064] 11 heat seal co-polymer / polymer film

[0065] 12 surface

Claims

Claims1. Thermal insulating element for fire protection of building equipment and industrial installations, the element (1) being in the form of a mineral wool wired mat, comprising a mineral wool mat (3) covered with a wire mesh (4) and an aluminum foil (2), especially as part of an intermediate layer (5) comprising the aluminum foil (2), on a major surface of the mat (3), characterized in that the aluminum foil (2) as such is perforated and / or the intermediate layer (5) as such is perforated.

2. Thermal insulating element according to claim 1, characterized in that the perforated aluminum foil (2) or the perforated intermediate layer (5) has a perforation pattern with 6 holes (6) per cm2to 60 holes (6) per cm2, preferably with 9 holes (6) per cm2to 50 holes (6) per cm2.

3. Thermal insulating element according to claim 1 or 2, characterized in that the holes (6) have a diameter between 0,1 mm and 0,5 mm, preferably of 0,2 mm.

4. Thermal insulating element according to claim 1, characterized in that the aluminum foil (2) and / or the intermediate layer (5) has an outer surface being provided with a coating (9) preferably made of a lacquer.

5. Thermal insulating element according to claim 1, characterized in that the wire mesh (4) is connected to the mat (3) by sewing with a thin wire (8) and / or a thread,6. Thermal insulating element according to claim 1, characterized in that the aluminum foil (2) or the intermediate layer (5) and the wire mesh (4) are fixed to the mat (3) by the same thin wire (8) and / or thread.

7. Thermal insulating element according to claim 4, characterized in that the coating (9) is applied to the aluminum foil (2) and / or the intermediate layer (5) with a surface weight between 9,0 and 11 ,4 g / m2.

8. Thermal insulating element according to claim 1 , characterized in that the aluminum foil (2) has a thickness between 15 and 20 microns, preferably of 16,5 microns.

9. Thermal insulating element according to claim 1 , characterized in that the aluminum foil (2) is part of a composite intermediate layer (5) comprising a film of a heat-seal co-polymer (11) and a reinforcement (10) of bi-directional fiberglass.

10. Thermal insulating element according to claims 1 or 2, characterized in that the holes (6) of the pattern are arranged in a regular patern with identical distances to each other in the machine direction of the aluminum foil (2) and / or the intermediate layer (5) and transverse to it.11 . Fire-resistant ventilation duct system comprising a sheet metal air duct and a layer formed of at least one thermal insulating element (1) for fire protection according to any preceding claims 1 to 10, characterized in that the overall fire resistance of the ventilation duct system fulfils requirements for at least EI30 according to EN 1366-1 :2014+A1 :2020, preferably at least EI60, more preferably EI90, even El 120 by providing an perforated aluminum foil (2), especially as part of an intermediate layer (5) comprising the perforated aluminum foil (2), on a major surface of the mat (3).

12. System according to claim 11 , characterized in that the perforated aluminum foil (2) and / or the intermediate layer (5) has a perforation patern with 6 holes (6) per cm2to 60 holes (6) per cm2, preferably with 9 holes (6) per cm2to 50 holes (6) per cm2.

13. System according to claim 11 or 12, characterized in that the holes (6) have a diameter between 0,1 mm and 0,5 mm, preferably of 0,2 mm.

14. System according to claim 11 , characterized in that the aluminum foil (2) and / or the intermediate layer (5) has an outer surface being provided with a coating (9) preferably made of a lacquer.

15. System according to claim 11, characterized in that the wire mesh (4) is connected to the mat (3) by sewing with a thin wire (8) and / or a thread.

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