GB2154873A - Heat-escape device for buildings - Google Patents

Abstract

A heat-escape device is proposed which comprises an outer covering of an easily fusible material in a thickness of material or shape which withstands snow and wind stresses and at least one further covering disposed beneath the said outer covering, the lower covering likewise being formed from an easily fusible or a pre-stressed material. This makes possible a thermal action almost without delay upon the outer covering, so that the latter frees the outlet opening for the escape of smoke and heat in the case of risk by melting. <IMAGE>

Description

SPECIFICATION Heat-escape device for buildings The invention relates to a heat-escape device for buildings, comprising an outer covering element, which covers a roof opening with a preferably rectangular cross-section and which is mounted on a holding ring, and at least one further inner covering disposed below the outer covering element.

Heat-escape devices of this type are provided in order to ensure the escape of hot combustion gases when unacceptably high temperatures occur, for example in the event of fire. Such heat-escape devices for buildings are known, but they have the disadvantage that they open by swinging up the covering after triggering by way of a triggering mechanism which has an energy store and is susceptible to breakdown and is expensive to maintain.

Two-sheet coverings, such as for example light domes, have already been used as heatescape devices. In the case of these light domes, however, the melting of the light domes lasts too long on account of the heat produced, since the lower sheet which is similar in shape and thickness of material to the upper covering must first melt and only then can the upper sheet melt. One-sheet arrangements have in particular the disadvantage of poor thermal insulation, so that not only does a heat loss from the building occur, but there is also the risk of condensation occurring.

In principle, the demands made upon building coverings are that they withstand the stresses which occur such as snow and wind stress and are constructed in a thermally insulating manner, and this has led in practice to double-sheet designs.

The object of the invention is to provide a heat-removing device for buildings which, depending upon the temperature occurring in the interior of the building, leaves the roof opening as free from obstruction as possible for the escape of heat and which in the closed state both provides good protection against heat loss and withstands the external stresses acting upon the covering element. In addition, the heat-escape device should be ready for operation without mechanically operating components and should not require maintenance.Starting from the consideration that a maintenance-free, automatically operating heat escape is achieved with a substantial degree of safety when the covering of the roof opening melts as a consequence of the heat produced, the object is attained in that the outer covering element consists of a material which easily melts under the action of heat and is constructed in terms of shape and thickness of material in such a way that it withstands the snow and wind stresses acting upon the building, and the inner covering disposed beneath the outer covering element consists of a material which likewise easily melts under the action of heat and which has a thickness such that it is used only for separating air layers.

A device of this type ensures that, when a specific temperature occurs, the inner covering first of all frees the access to the outer covering element without delay, and when the raised temperature continues the outer covering element is then exposed to the heat present and can rapidly melt. This process occurs in a short period of time determined by safety considerations. In this connexion the outer covering element can be constructed in the form of light dome for example and can have such strength that it withstands the stresses acting from the outside, e.g. wind or snow stress. Nevertheless, on account of the corresponding arrangement of the inner covering an adequate thermal insulation is produced.

In order to improve the thermal insulation still further, it has proved to be expedient for the inner covering to comprise a plurality of covering elements arranged at a distance from one another. This ensures that a thermally insulating air cushion can be formed betweenthe individual covering elements of the inner covering, so as to improve the thermal insulation. According to a further development of the invention it can be provided that at least one of the covering elements comprises prestressed material which is torn apart when subjected to heat. This in turn has the advantage that the smoke passage can be freed more rapidly than in the case of the melting procedure. In this connexion the pre-stressing can be selected in such a way that the opening can be freed over its entire cross-section.

Expedient materials for producing the outer covering element have been found to be extruded acrylic glass. PVC or a comparable material. These materials have a suitable melting behaviour.

Embodiments are diagrammatically illustrated in a simplified manner in Figs. 1 to 3, in which Figure 1 shows an embodiment with an inner covering, Figure 2 shows an embodiment in which the inner covering consists of two covering elements, and Figure 3 shows an embodiment suitable for a corrugated asbestos cement roof or a profiled sheet metal roof and having an inner covering element.

In the embodiment illustrated in Fig. 1 a holding ring 3 is mounted on the roof closure 1 with the roof opening 2. The holding ring 3 supports a covering element 4 in known manner, which in the embodiment is a light dome.

The latter consists of an easily melting, translucent material, e.g. extruded acrylic glass of sufficient strength for it to withstand the exter nal stresses which occur. A further covering 5, which in the embodiment illustrated consists of a covering element adapted to the shape of the light dome, is disposed beneath this light dome. In this arrangement, thermal insulation is provided between the inner covering and the outer covering element by way of the air present between the covering elements. In addition, the inner covering ele ment consists of an easily melting or prestressed material and it is likewise translucent.

If, in the event of fire, hot gases pass through the roof opening 2 and act upon the inner covering 5, the said covering element will quickly melt and the hot gases will act upon the outer covering element 4 almost without delay and will likewise rapidly melt or tear the latter, so that the hot gases can immediately escape. In the case of the embodiment according to Fig. 2 the inner covering 5 com prises three covering elements 5a, 5b and 5c, as a result of which a greater degree of thermal insulation is produced with an only neglibly delayed opening of a passage by the hot gases. Finally, Fig. 3 shows a special embodiment for direct fitting in the case of a corrugated asbestos cement roof or a profiled sheet metal roof. In this case the edge is integrally formed in the outer covering 4 and is adapted on all sides in an angled manner to the structure of the roof. In this case the inner covering 5 in the area projecting beyond the roof opening is likewise adapted to the structure of the roof, so that it lies on the roof closure 1 with the outer roof covering 4 and is secured. In this case the mode of functioning is the same as in the embodiments described above. Here too it is possible for the covering 5 to be formed from a plurality of covering elements. A heat-escape device formed as a direct function of the hot gases to be removed is described with the arrangement according to the invention.

Claims (5)

1. A heat-escape device for buildings, comprising an outer covering element. for covering a roof opening and of a material which easily melts under the action of heat and is constructed in terms of shape and thickness of material in such a way that it withstands the snow and wind stresses acting upon the building, and at least one inner covering disposed beneath the outer covering element and of a material which likewise easily melts under the action of heat.

2. A heat-escape device according to claim 1, wheren the inner covering comprises a plurality of spaced covering elements.

3. A heat-escape device according to claim 1 or claim 2, wherein at least one of the covering elements comprises pre-stressed material which is torn apart when subjected to heat.

4. A heat-escape device according to any one of claims 1 to 3, wherein the covering elements comprise extruded acrylic glass or PVC.

5. A heat-escape device substantially as hereinbefore described with reference to and as illustrated in any one of the accompanying drawings.