EP0096308B1 - Fire-resistant layer - Google Patents

Abstract

1. A fire-protection strip, in particular for a roof covering, with a flame-proof strip (2) which is disposed directly on at least one side of a sealing strip (1) and which at elevated temperature gives off a non-combustible fluid particularly in vapour form, characterized in that the fire-protection strip (2) is laid on the upper side of the roof or the like and the flame-proof strip faces the upper side.

Description

The invention relates to a fire protection membrane, in particular for roof covering, according to the features of the preamble of claim 1 (DE-A-2 900 535).

Preventive fire protection is currently carried out with great effort in industrial construction. So smoke extraction systems, fire protection doors and sprinkler systems have long been state of the art. However, preventive measures are largely dispensed with, particularly when covering roofs and other areas. Ultimately, the reason for this is that no suitable measures are available to date. The installation of non-combustible insulation materials does not significantly improve the fire behavior. On the contrary, depending on the building material. B. with a fiber insulation by wicking the fire can be worsened. Added to this is the fact that one cannot usually do without combustible building materials, particularly with roof coverings. For example, a roof covering needs a sealing membrane to cover it against weather influences. Such sealing sheets are usually plastic films or bituminous sealing or roofing sheets which, for. B. also be called «roofing felt. But it is precisely for these geomembranes that insulating materials result in the dangerous wicking effect of the fire. Incidentally, insulation class A according to DIN 41 02, such as. As perlite, mineral fibers or foam glass can be used. For cost and weight reasons, you often have to be satisfied with insulation materials of fire class B according to DIN 41 02. These insulation materials are intended to ensure temperature insulation, especially, of course, if there is no fire. All of this applies particularly to roof coverings, such as those currently used in large-scale commercial buildings, e.g. B. for supermarkets, are common.

These buildings are all the more dangerous since they lack fire protection on the roof. The particular danger of such flat roofs lies in the fact that the supporting structure is burdened by the fire up to the point of collapse of the burning sub-area. Loading with gravel or other incombustible slab coverings also has a disadvantageous effect, especially since this significantly reduces the service life in the event of a fire.

This causes a burn through the collapsed roof; As a result, the flames from inside the building can reach and ignite the combustible roofing materials, especially the waterproofing membrane. But since it is in the roofing material, such as the waterproofing membrane. basically deals with petrochemical products, the roof fire will then proceed like an oil fire. Extinguishing water is usually not the appropriate means, so that only special extinguishing agents from special fire departments can be used, which means a further delay and complication in the event of a fire.

The prior art DE-A-2900535 relates to fire protection thermal insulation, which is characterized in that it contains or consists of a hardened thermosetting synthetic resin material in which an effective amount of a finely divided, crystalline, hydrated, inorganic salt extender dispersed, which is sufficient to achieve a predetermined level of fire resistance, determined in particular according to the ASTM method E-119-76 or another fire resistance test method. wherein the hydrated extender contains at least 35% by weight water of crystallization, the major portion of which is released when heated to a temperature within the range from about 93 ° C but below about 316 ° C (200 to 600 ° F). This insulation relates to sandwich structures in which adhesives are used to connect the layers.

The sandwich structure also includes a thermal barrier made of normal resin with hydrated salt and inorganic fillers. In such a sandwich panel, the individual layers are firmly connected to one another.

The arrangement of water-releasing products behind the outer layers is intended to provide a temperature barrier to protect the combustible hard foam core. Because they are firmly connected, these layers can only be effective at certain points (passive fire protection).

• Die Temperatur der punktuellen Beflammung wird allmählich durch die äußere Schicht hindurchgeschlagen. Die Kristalle werden Wasser abspalten. Aus dem Kristallwasser wird Wasserdampf werden. Der Dampfdruck wird allmählich das Sandwich trennen. Der Wasserdampf wird an irgend einer Stelle an die Atmosphäre entweichen und damit seine Wirksamkeit verlieren. Es handelt sich um punktuellen Brandschutz mit verzögernder Wirkung.

This sandwich element will function as follows in the event of selective fire exposure:

• The temperature of the selective flame is gradually passed through the outer layer. The crystals will split off water. Water vapor will become from the crystal water. The vapor pressure will gradually separate the sandwich. The water vapor will escape to the atmosphere at some point and thus lose its effectiveness. It is selective fire protection with a delaying effect.

Furthermore, the prior art includes DE-B-2349666 and DE-A-2 234 291 corresponding to FR-A-2 145 709.

DE-B-2 349 666 describes a plastic sheet, for example made of PVC soft, preferably for the sealing of unmarked, single-skin roofs or the like, with a fire protection layer, which is characterized in that the fire protection layer is embedded in the plastic sheet, in particular, that the fire protection layer is covered on all sides by the plastic sheet.

FR-A-2145709 relates to a non-combustible plate-shaped construction element consisting of seven layers, whereby Water is released in the event of a fire, which is used for foam formation.

The state-of-the-art fire protection membranes offer inadequate protection and do not guarantee that the fire will not spread.

• 1. Insgesamt eine wesentliche Verminderung der Brandlast ;
• 2. nach Möglichkeit keine Verwendung von brennbaren Klebemitteln ;
• 3. Abschottung zwischen brennbarer Dachdichtung und Dämmstoff ;
• 4. unterhalb des Dämmstoffes Dampfsperren, ohne, bzw. mit geringster Brandlast ;
• 5. Verhinderung des fortschreitenden Brandgeschehens durch geeignete Maßnahmen.

In contrast, the present invention is based on the following tasks:

• 1. Overall, a significant reduction in the fire load;
• 2. If possible, no use of flammable adhesives;
• 3. partitioning between combustible roof seal and insulation material;
• 4. Vapor barriers below the insulation, without or with the lowest fire load;
• 5. Prevention of the progressive fire by appropriate measures.

The most important of these is the fulfillment of the latter requirement, ie to effectively prevent progressive fire events; but it has not yet been resolved either. The invention is therefore based on the object of eliminating the risk of burn-through and progressive fire events such as a widespread conflagration in a fire protection membrane according to the preamble of claim 1. This object is achieved by the features specified in the characterizing part of claim 1.

It has now surprisingly been found that this core requirement is met by a fire protection membrane which consists of a sealing membrane of a known type, e.g. B. of the type mentioned above, on whose at least one side an additional flame retardant membrane is arranged. In principle, it is a two-layer fire protection membrane, consisting of a sealing membrane and a flame protection membrane. The type of flame retardant membrane is essential. According to the invention, such a flame retardant membrane is understood to mean one. which is an incombustible liquid, such as e.g. B. water, in vapor form; she can also do it. emitting gases, such as B. nitrogen. As a flame retardant membrane in the sense of the invention, for. B. a glass fiber fleece impregnated with water glass is particularly suitable. A fire protection membrane of this type is known from the prior art.

Fire protection membranes based on glass fiber fleece are generally suitable, in which crystalline water is embedded. So z. B. water-saturated diatomaceous earth as the base material for the flame retardant membrane in question. Such water-containing substances only release their loosely bound water at around 100 ° C; sometimes they also foam up. In the case of water-containing ammonium phosphates as the base material for the flame retardant membrane there is an additional advantage that fire-emitting gases, e.g. As nitrogen, are released. It has now surprisingly been found that this combined fire protection sheet completely prevents the fire from progressing on the combustible sealing sheet. One should actually believe that, especially in the case of foaming flame-retardant membranes, due to the wicking effect for the waterproofing membrane, they further worsen the fire. However, the opposite is the case. For example, DE-A-2 807 697 mentions ammonium phosphate as an example, which also has a foam-forming effect. There are also resins, for example urea-formaldehyde resin or the like, and carbohydrates or glue. This substance composition forms a tightly coherent, porous, carbon-containing foam in the flame. Such compositions of matter are also known from the following patents or documents relating to patent applications: DE-C-962 824, DE-B-1 061 011, DE-B-1065116. DE-A-1 644 780, DE-A-1 794 343 and DE-A-2200 104. According to this prior art it is also known to apply these substance compositions in pasty form to glass silk fabric or nonwovens; this results in flame retardant strips. As heat-decomposable organic nitrogen compounds for releasing heat-emitting gases, above all compounds of the type of urea, melamine or dicyandiamis are mentioned in this prior art, i. H. those containing nitrogen bound in amide-like form. According to this state of the art, however, the proportion of water or solvent is expressly only of importance for the processing of the compositions of matter and depends on the requirement that the mass must be spreadable, fillable or also flowable. (See e.g. DE-A-2 807 697 on page 6 in lines 13 to 16). Thus, according to the prior art, only the purely foaming effect of these substances is known, possibly together with the release of nitrogen. However, it cannot be understood from this state of the art that such flame retardant membranes, despite the wicking effect for the sealing membrane, actually worsen the fire.

One possible explanation for this is that in the case of water evaporated from the flame retardant membrane, it condenses on the sealing membrane. Due to its high evaporation heat, it therefore acts as a heat-absorbing layer, which prevents the sealing membrane from igniting. This effect is possibly enhanced by the fire-emitting gases.

Evidently, water vapor is drawn from the colder, not yet flamed parts of the sealing membrane into the flamed parts of the sealing membrane at a higher temperature; the same applies to the fire-emitting gases. As a result, the fire-retardant effect is concentrated precisely where it is most necessary. This seems to be the case for gases according to the relevant physical laws caused pressure differences due to temperature differences (Knudsen effect or thermal diffusion).

Such a fire protection membrane according to the invention can also be used for retrofitting conventional roof coverings; for this purpose, the fire protection membrane according to the invention is placed on the top of the roof covering with the flame protection membrane.

The retrofitting is already done. Experience has shown that a flame retardant membrane of approx. 1 mm thickness is sufficient; Flame retardants that are too thick are less and less suitable.

The fire protection sheet is completed by an insulation sheet which is arranged on at least one free side of the flame protection sheet. Any of the aforementioned insulation materials can be used as the base material for such an insulation sheet. In the event of a fire, the insulation membrane additionally provides heat insulation between the flame protection membrane with the sealing membrane and the remaining free side of the insulation membrane, which is the underside of the roof in the case of a roof. A foaming flame-retardant membrane can still act between the sealing membrane and the insulating membrane as a barrier for any combustible gases from the membrane.

For additional security, a further vapor barrier sheet can then be arranged on the remaining side of the insulation sheet.

• Aufbau I: Verzinktes Trapez-Blech, darauf Dampfsperre (Kunststoff beschichtete Aluminiumfolie) von 110 Mikrometern, darauf eine Mi- neralfaserplatte Brandschutzklasse A 1 von 100 Millimetern, darauf eine erfindungsgemäße Flammschutzbahn von 1 Millimeter und schließlich eine Abdeckfolie von 2 Millimetern ;
• Aufbau II : Wie Aufbau I jedoch ohne Dampfsperre ;
• Aufbau III: Trapez-Blech, Perlite-Platten von der Brandschutzklasse B 2, Flammschutzbahn wie bei Aufbau I und Abdeckfolie wie bei Aufbau I;
• Aufbau IV : Wie Aufbau 111 jedoch mit Dampfsperre.

In the case of a self-supporting roof, such a fire protection sheet can be arranged on a galvanized trapezoidal sheet known per se. The following roof structures were tested in detail:

• Structure I: Zinc-coated trapezoidal sheet metal, with a vapor barrier (plastic-coated aluminum foil) of 110 micrometers, a mineral fiber board with fire protection class A1 of 100 millimeters, a flame retardant membrane according to the invention of 1 millimeter and finally a cover foil of 2 millimeters;
• Structure II: Like Structure I but without a vapor barrier;
• Structure III: trapezoidal sheet, Perlite panels of fire protection class B 2, flame retardant membrane as in structure I and cover film as in structure I;
• Setup IV: Like setup 111, but with vapor barrier.

A conventional propane gas burner would be held at a distance of approx. 25 cm from above onto the cover film, i.e. the sealing membrane. In all superstructures, the outer cover sheet, i.e. the sealing membrane, burned outwards under the influence of the gas flame and went out after a maximum of 13 minutes at a distance of approx. 25 to 30 cm from the gas burner. The insulating material, i.e. the insulation sheet, was indeed annealed downwards in the shape of a cone; however, the sheet surface showed no changes. The size of the burn mark was a maximum of 58 cm in diameter for all structures. While the temperatures in the firing center reached values in the range of 1,000 ° C after approx. 2 to 3 minutes, they remained almost constant at this temperature over the test period. At a distance of 30 cm from the focal spot, only temperatures of maximum 100 ° C were measured. With insulation material of fire protection class B 2, the maximum temperature was 100 ° C at a distance of 45 cm. In all cases, the sheet temperatures deviated only slightly from the ambient temperature.

In summary, the tested superstructures only continued to burn independently for a maximum of 12 to 13 minutes despite constant flaming and were only destroyed with a maximum diameter of 58 cm. At a distance of 30 or 45 cm, only temperatures of a maximum of 100 ° C were measured. The temperature of the trapezoidal sheets did not change compared to the ambient temperature.

An independent fire propagation on the surface of the insulating layer, in particular on the sealing membrane, or the beads of the trapezoidal sheets was not observed.

This fulfills all of the original basic requirements. The fire load is significantly reduced; flammable adhesives are not required; the combustible roof seal, i.e. the sealing membrane, is sealed off from the insulation material; if necessary, there is a vapor barrier without or with the lowest fire load underneath the insulation material, i.e. the insulation membrane. The fire is practically completely hampered.

• Figur 1 die perspektivische Ansicht einer erfindungsgemäßen Brandschutzbahn ;
• Figur 2 eine erfindungsgemäße, selbsttragende Dacheindeckung nach der Brandschutzbahn.

An embodiment of the invention is shown in the drawings. Show it :

• Figure 1 is a perspective view of a fire protection membrane according to the invention;
• Figure 2 shows a self-supporting roof covering according to the invention after the fire protection membrane.

In Figure 1, an element of the fire protection membrane according to the invention is shown in a perspective view. The sealing membrane is identified by reference number 1. It is broken up in part of its surface so as to make the surface of the flame retardant membrane 2 visible. The fleece structure of the flame retardant membrane 2 is indicated by irregular patterns. The smooth nature of the sealing membrane 1, however, is indicated by a thin line hatching.

The sealing membrane 1 is arranged on the flame retardant membrane 2. In the case of water glass or silicate base materials of the flame retardant membrane, a one-piece connection between the sealing membrane and the flame retardant membrane can be achieved by simple water bonding; the adhesive properties of water glass have long been known.

FIG. 2 shows a section of a fire protection membrane for a roof covering. Again, the sealing membrane 1 is hatched by oblique lines; the flame-retardant membrane 2 is also illustrated with its non-woven structure by irregular hatching. Sealing membrane 1 and flame retardant membrane 2 are in the Broken open foreground of illustration; as a result, the insulating sheet 3 arranged on the remaining side of the flame retardant sheet 2 is then visible, which in turn has broken open again in order to make the trapezoidal sheet visible as a supporting part. The insulation sheet 3 is shown dotted to indicate its porous structure. Not shown is a possible vapor barrier film between the insulation sheet 3 and the trapezoidal sheet 4. The reference number 5 denotes a retaining tab which is held against the trapezoidal sheet by screws; ordinary sheet metal screws are particularly suitable as screws. This mechanical anchoring safely absorbs the wind loads and combustible parts under the flame retardant membrane are no longer required. The fire load is also reduced by saving on adhesive layers.

The roof covering shown in FIG. 2 can be brought onto the market in particular as a fully assembled roof covering element, that is to say as a multi-layer panel.

• 1 Dichtungsbahn
• '2 Flammschutzbahn
• 3 Dämmbahn
• 4 Trapez-Blech
• 5 Haltelasche
• 6 Blechtreibschraube

List of reference numerals:

• 1 sealing membrane
• '2 Flame retardant membrane
• 3 insulation sheet
• 4 trapezoidal sheet
• 5 retaining tab
• 6 self-tapping screw

Claims (8)

1. A fire-protection strip, in particular for a roof covering, with a flame-proof strip (2) which is disposed directly on at least one side of a sealing strip (1) and which at elevated temperature gives off a non-combustible fluid particularly in vapour form, characterised in that the fire-protection strip (2) is laid on the upper side of the roof or the like and the flame-proof strip faces the upper side.

2. A fire-protection strip according to Claim 1, characterised in that an insulating strip (3) is disposed on at least one free side of the flame-proof strip (2).

3. A fire-protection strip according to Claim 2, characterised in that a vapour barrier strip is disposed on the free side of the insulating strip (3).

4. A fire-protection strip according to any of the preceding Claims, characterised in that at high temperatures the flame-proof strip (2) also gives off fire-inhibiting gases.

5. A fire-protection strip according to any of the preceding Claims, characterised in that at high temperatures the flame-proof strip (2) gives of steam.

6. A fire-protection strip according to any of the preceding Claims, characterised in that at high temperatures nitrogen is liberated by the flame-proof strip (2).

7. A fire-protection strip according to any of the preceding Claims, characterised in that the flame-proof strip (2) contains crystalline water bound in water glass or diatomaceous earth.

8. A fire-protection strip according to any of the preceding Claims, characterised in that the flame-proof strip (2) contains hydrous ammonium phosphate.

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