GB2144164A

GB2144164A - A glazed unit capable of withstanding the impact of an explosion

Info

Publication number: GB2144164A
Application number: GB08416264A
Authority: GB
Inventors: Heinrich Salzer
Original assignee: Individual
Current assignee: Individual
Priority date: 1983-07-28
Filing date: 1984-06-26
Publication date: 1985-02-27
Also published as: GB2144164B; TR22489A; ZA845840B; IT1176421B; GB8416264D0; IT8421941A0; BE900221A; ES289206U; IT8421941A1; ES289206Y; CH667127A5; FR2551796B1; FR2551796A1

Abstract

Two parallel panes 1 and 2 have a space 4 between which is connected by way of openings 33 to the atmosphere on the attack-endangered side of the unit. The openings 33 are located between a composite frame 10 mounting pane 1 and an outer frame 3 which receives the frames 5,6,9,10. If an excess pressure occurs in the space 4 which cannot be reduced to a sufficient degree by way of the openings 33, the excess pressure causes the members, 12 to burst off the snap-fittings 13. The panes may be of polycarbonate and may be laminated. <IMAGE>

Description

SPECIFICATION A glazed unit capable of withstanding the impact of an explosion This invention relates to a glazed unit capable of withstanding the impact of an explosion comprising two panes of glass which are each bordered by a respective frame and which are arranged parallel to one another and at a spacing from one another inside a common outer frame.

It is generally known to use laminated glass panes for such glazed units. The previously known laminated glass units do not, however, satisfy the extreme demands which are made on explosion-proof glazed units. For example, if an explosive charge is situated immediately adjacent the outer surface of the window, the resultant blast will destroy all the panes of glass and leave the window opening empty.

A glazed unit consisting of laminated glass which is designed to withstand explosive impacts and which is distinguished by an improved capacity for resistance to explosive blast pressure is known from German Offenlegungsschrift No. 3045 833. The improvement in the capacity for withstanding explosive impacts is achieved in that the glazed unit comprises at least two panes of laminated glass which are arranged with an air spacing therebetween and which are in each case surrounded by a closed frame consisting of steel profiles of L-shaped cross-section.The limb of the steel profile which forms the edge surface of the frame is directed towards the side of the unit remote from the site of explosion and a gap of at least 10 mm, which is filled up by a permanently-elastic plastics material with a Shore hardness of from 250 to approximately 600 Shore, exists between the inner surfaces of the steel frames and the glass surfaces.

The improved resistance to explosive impact achieved with the known glazed unit is attributed to the fact that a resilient intermediate layer with a minimum thickness of 10 mm is arranged between the frames which have high strength and the laminated glass panes. As a result of this elastic intermediate layer a resilient supportforthe laminated glass pane is supposed to be achieved, which is supposed to be particularly favourable and effective particularly in the case of brief explosive blasts of extremely high force. In the case of the known glazed unit, particular importance is also attributed to the arrangement of an air gap between two panes of laminated glass units, because in this way the pressure wave generated by an explosion is severely damped.

In tests, it has become apparent that a resilient support for the laminated glass panes in conjunction with the arrangement of an air gap between two glass panes does indeed, as compared with conventional glazed units, damp the pressure wave which occurs upon an explosion. However, this arrangement does not prevent destruction of the pane of glass spaced behind the one facing the explosive blast when an explosive charge is situated directly adjacent the latter pane because, despite the damping action, even reduced pressure is still so great that the second pane of glass cannot withstand this.

Of course, it is possible to make the panes of glass so large and to make the air space therebetween so wide that the glazed unit withstands even a scarcely damped pressure wave. The cost of doing this is, however, so considerable that it cannot economically be accepted.

The object of the present invention is to provide a glazed unit of the kind mentioned at the beginning hereof which does not require any panes of glass which are independently extremely resistant in order to guarantee a very high resistance to explosive impacts.

This object is achieved in that sealable openings are provided between the edge of the pane of glass which faces the attack-endangered side and the outer frame so as to connect the space between the two panes of glass to the space situated on the attack-endangered side of the unit.

As a result of the openings in accordance with the invention, which can be sealed with easily releasable covers, there arises, upon an explosive impact a connection of the space between two panes of glass with the space situated on the attack-endangered side. Thus, the pressure arising upon an explosion is able to destroy the pane of glass facing the attackendangered side, but the pressure peak is reduced, so that the maximum pressure cannot have an effect on the following pane or panes of glass units, all the more so since compression of the air inside the space between two panes of glass cannot on account of the openings rise to an extent which endangers the pane or panes of glass therebetween.

With the glazed unit in accordance with the invention it is even possible to arrange the pane or panes of glass not facing the attack-endangered side in a swivellable or rotatable frame, so that these panes of glass can be adjusted so that the openings provided for pressure relief in the event of an explosion can also be used for ventilation.

The openings may be provided in the frame of the pane of glass which faces the attack-endangered side and/or between this frame and the outer frame.

As a result of this the outer frame, which can be formed from brickwork, does not need any processing or precautionary measure in order to accommodate the openings. The openings, which can also have the form of slots also require no additional processing of the inner frames around the panes of glass insofar as the openings are, in accordance with the invention, provided between the inner frame or frames and the outer frame.

Preferably the frame which has the openings and/or bounds the openings, of the pane of glass facing the attack-endangered side includes frame portions which are connected by way of spacers or distance pieces to the frame of the adjacent pane of glass unit or the outer frame. These frame portions can also form seals of additional openings.

As a result of this developmert, a frame along the lines of blend frame, which is connectable by way of spacers or distance pieces to the frame of the adjacent pane of glass unit or to the outer frame, can be assembled from frame portions around the pane of glass facing the attack-endangered side. The frame portions can be so dimensioned that between these and the outer frame slot shaped openings remain, by way of which the space between two panes of glass is connected to the space at the attack-endangered side of the unit. The two spaces receives an enlargeable connecting cross-section when the frame portions are connected to the distance pieces in an easily releasable manner so that they can be blasted off by explosive pressure. In this way, the frame portions may be said to represent closures of additional openings.

The frame portions may advantageously consist of substantially U-shaped covering profiles which form a blend frame and which are releasably held by way of clamping parts which are fastened to the spacers or distance pieces or formed integrally with the spacers or distance pieces. As a result of this development, a comparatively slight excess pressure between the pane of glass facing the attackendangered side and the subsequent pane of glass is sufficient to loosen the frame portions from the spacers or distance pieces and thus reduce this excess pressure suddenly, insofar as it is not reduced by way of the openings which are already present between the blend frame and the outer frame.

In contrast to the U-shaped covering profiles, the clamping parts are fastened securely to the spacers or distance pieces, so that bands can be provided to hingedly connect the frame of the relevant pane of glass to clamping parts of frame portions at one side of a blend frame. As a result of this development, even the pane of glass unit facing the attackendangered side can be provided with a swingable or tiltable frame which is preferably smaller in its dimensions, as compared with the frame of a following pane of glass unit, by such an amount that the pane of glass facing the attack-endangered side can be swung into the interior of the building for example for cleaning purposes.

Each clamping part which is fastened by way of a spacer or distance piece to the outer frame or to the frame of the following glass unit or is formed integrally with the spacer or distance piece preferably consists of a substantially U-shaped profile piece which is fastened by its web to the respective spacer or distance piece or is integrally formed with same and has limbs directed towards the attackendangered side which are clasped by limbs of the covering profile which is similarly substantially U-shaped.

As a result of this design, the U-shaped covering profiles are given a sufficiently stable fixing and yet they can, nevertheless, in the event of an explosion burst off sufficiently reliably from the clamping parts.

An adequate fixing of the covering profiles along with maintenance of the ability to burst off in the event of an explosion is assisted if the limbs of the profile pieces forming the clamping parts, and the limbs of the covering profiles forming the blend frame have on contiguous surfaces engeagable and disengageable projections or depressions respectively.

Finally, it can additionally be advisable to arrange pressure elements, introduced under bias and aligned perpendicularly to the plane of the glazed unite between the frames and/or between the edge regions, adjacent to the frames, of the panes of glass.

These pressure elements, which can consist for example each of a pair of telescopic sleeves with a compression spring arranged therein, are suitable as an alternative to rigidly-designed distance pieces, By way of the pressure elements the pane of glass facing the attack-endangered side, together with its frame, in the event of an explosion initially yields elastically against the force of the pressure elements without an excess pressure which endangers the following pane of glass being able to build up inside the space between the panes of glass. Also as a result of this design the peak of a pressure wave can be intercepted, so that in the appropriate circumstances even the pane of glass facing the attackendangered side withstands the explosion, (unless of course this results from a so-called sticking charge which was securely connected directly to the pane of glass).

The invention will be described further, by way of example, with reference to the accompanying drawings, in which; Figure 1 is a partial cross-section of a first embodiment of the glazed united of the invention in which a frame of the glass pane facing the attackendangered side is connected to the frame of the other glass pane; Figure 2 is a similar view of a second embodiment of the invention in which the frame of the glass pane facing the attack-endangered side is fastened to an outer frame; Figure 3 is a similar view of a third embodiment of the invention in which the frames of the two glass panes are connected together by distance pieces which are designed as pressure elements; and Figure 4 is a similar view of a fourth embodiment of the invention in which the frame of the glass pane facing the attack-endangered side is connected by pressure elements to angle pieces fastened to the outer frame.

The glazed units shown in each case only in partial cross-section comprise of pane of glass 1 which faces the attack-endangered side and which can consist, for example, of polycarbonate, and a second pane of glass 2 which is averted from the attackendangered side and which is stronger in design.

The panes of glass 1 and 2 are arranged parallel at a spacing from one another inside an outer or soffit frame 3 and define, together with the outer frame 3, a space or chamber 4.

In all the exemplified embodiments, the pane of glass 2 is provided with a casement frame 5 and a combination or blend frame 6, which are connected to one another hingedly by way of bands 7. The combination or blend frame 6 is fastened by means of screws 8 to the outer frame 3.

The pane of glass 1 is provided, in the embodiments shown in Figures 1 and 2, with a casement frame 9 and a combination or blend frame 10 or 10' respectively which are also connected hingedly to one another by way of bands 11. The blend frames 10 and 10' consist of frame portions in the form of U-shaped covering profiles 12.

In the embodiment shown in Figure 1, the Ushaped covering profiles 12 are clamped onto similarly U-shaped profile pieces 13 which are seated on distance pieces 14 and are fastened by means of screws 15 to the blend frame 6 of the pane of glass 2.

In the embodiment shown in Figure 2, the Ushaped profile pieces 12 are clamped onto similarly U-shaped profile pieces 13' having integrally formed angle pieces 16. The profile pieces 13' are fastened by way of the angle pieces 16 by means of screws 17 directly to the outer frame 3. Also, in the web part of the U-shaped profile pieces 13' there are apertures 18 which are advantageous when the profile pieces 13' exceed a specific length.

In the embodiments shown in Figures 3 and 4, the pane of glass 1 is provided with a single fixed frame 19 which similarly consists of frame portions in the form of U-shaped covering profiles 20. The Ushaped covering profiles 20 are clamped to similarly U-shaped profile pieces 21, which are provided in their web parts with perfortions 22, insofar as they exceed a specific length.

In the embodiment shown in Figure 3, pressure elements 23 are fastened by means of screws 24 and 25 between the profile pieces 21 and the blend frame 6 of the pane of glass 2. The pressure elements 23 consist of two sleeve-like parts 26 and 27 which can be slipped telescopically one into the other and inside which a compression spring 28 standing under bias is arranged.

In the embodiment shown in Figure 4, the pressure elements 23 are arranged between the profile pieces 21 and angle pieces 29 which are fastened by means of screws 30 directly to the outer or soffit frame 3.

In all the illustrated embodiments the limbs of the U-shaped covering profiles 12 or 20 respectively are provided with projections 31 which engage into depressions 32 of the limbs of the U-shaped profile pieces 13, 13' or21 respectively.

Finally, the space 4 between panes of glass 1 and 2 communicates, in all the embodiments, by way of openings 33 with the space situated on the attack endangered side of the unit so that no excess pressure can build up in the space 4 to endanger the pane of glass 2. As shown in Figures 2 and 3 the openings 33 can be sealed by an easily releasable sealing profile 34.

If the cross-section of the openings 33 is not sufficient for adequate pressure relief of the space 4, upon a comparatively slight pressure rise in the space 4 the U-shaped covering profiles 12 or 20 respectively are burst off from the profile pieces 13, 13' or21 respectively and in this way enlarge the connecting cross-section between the space 4 and the space on the attack-endangered side of the glazed unit.

Claims

1. A glazed unit capable of withstanding the impact of an explosion comprising two panes of glass which are each bordered by a respective frame and which are arranged parallel to one another and at a spacing from one another inside a common outer frame, characterised in that sealable openings are provided between the edge of the pane of glass which faces the attack-endangered side and the outer frame so as to connect the space between the two panes of glass to the space situated on the attack-endangered side of the unit.

2. A glazed unit as claimed in Claim 1 wherein the openings are provided in the frame of the pane of glass which faces the attack-endangered side and/or between this frame and the outer frame.

3. A glazed unit as claimed in Claim 2 wherein the frame which has the openings or which bounds the openings includes frame portions which are connected by way of spacers or distance pieces to the frame of the adjacent pane of glass and which form seals of additional openings.

4. A glazed unit as claimed in Claim 3 wherein the frame portions consist of substantially U-shaped covering profiles which form a blend frame and which are releasably held by clamping parts which are fastened to the spacers or distance pieces or are formed integrally with the spacers or distance pieces.

5. A glazed unit as claimed in Claim 4 wherein a casement frame of the pane of glasss facing the attack-endangered side of the unit is hingedly connected to clamping parts for the frame portions at one side of the blend frame.

6. A glazed unit as claimed in Claims 4 and 5 wherein each clamping part consists of a substantially U-shaped profile piece which is fastened by its web to a respective spacer or distance piece or is formed integrally with a spacer or distance piece and has directed towards the attack-endangered side which are clasped by limbs of the covering profile which is similarly substantially U-shaped.

7. A glazed unit as claimed in Claim 6 wherein the limbs of the profile pieces forming the clamping parts and the limbs of the covering profiles forming the blend frame have projections or depressions on contiguous surfaces which can be engaged and disengaged.

8. A glazed unit as claimed in any preceding Claim wherein the spacers or distance pieces comprise pressure elements which are introduced under bias and which are aligned perpendicularly to the plane of the glazed unit are arranged between the frames and/or between the edge regions, adjacent to the frames, of the parallel panes of glass.

9. A glazed unit capable of withstanding the impact of an explosion substantially as hereinbefore described with reference to and as illustrated by Figure 1, or Figure 2 or Figure 3, or Figure 4 of the accompanying drawings.