IL103135A - Blast resistant window - Google Patents

Description

ViY a >33-i T»Dy ii n BLAST RESISTANT WINDOW BLAST RESISTANT WINDOW The present invention relates to windows designed to seal a protected space so as to prevent the leakage of gas into the protected space as well to eliminate the effects inside the protected space of blasts or explosions taking place outside the protected space.

The recently concluded Gulf War with its Scud attacks on civilian populations has emphasized the need to equip civilian residences with a protected space which will be capable of withstanding both a conventional attack using explosives and a non-conventional attack involving chemical or biological weapons .

Before the Gulf War it was generally accepted that the civilian population on the home front is sufficiently protected by air raid shelters, which are reinforced concrete structures located in the basement of an apartment building. Air raid shelters are designed primarily to protect civilians from conventional attacks with explosives. When so warranted by conditions, the residents of an apartment building would enter the shelter to seek protection from explosions.

The Scud attacks on civilian populations in the Gulf War of 1991 has demonstrated that conventional shelters have certain serious limitations. First, the possibility of the use of chemical and/or biological weapons against civilian populations has become more real. Second, it became clear that modern weapons delivery systems, such as ballistic missiles, require but a few minutes or less from the time they are launched until they reach their targets.

Conventional shelters are considered to be inadequate as against chemical or biological warfare for a number of reasons. First, conventional shelters are typically located at or below ground level. Since the released chemical and biological components of such non-conventional weapons are heavier than air, they would tend to accumulate and do most damage at or below ground level, i.e., precisely where the conventional shelters are located. Furthermore, the doors and windows of conventional shelters are designed mainly to withstand blasts.

Secondly, in the age of missiles which take but a minute or two from the time they are first detected until they reach their target, conventional shelters are simply located too far from most of the people they are designed to protect .

As a result of lessons learned in the Gulf War, there is now a move, stimulated by new regulations by the Israel Defense Ministry, to shift emphasis from conventional shelters and to replace them, at least in new residential construction, with protected spaces, or rooms, located in each apartment or, at least, on each floor of an apartment building .

The protected space will have characteristics which will make it suitable to withstand either a conventional explosive attack or a chemical or biological attack.

Each of these protected spaces will be provided with a door opening to the interior of the building which should be gas tight and which should resist blasts. In addition, those protected spaces which have an exterior wall as one of their walls may also have a window. This is especially true of individual protected spaces which, except in emergencies, serve as a room in an apartment. For example, one of the bedrooms in the house may be a protected space.

During normal times the bedroom, whose walls typically include one or two exterior walls, needs to function as a normal bedroom, which normally means having at least one window to the outside of the building.

Such a window arrangement must withstand anticipated direct explosion blasts and blast fragments while at the same time not allowing gases or biological organisms to entre the protected space. The blast resistance and the sealing functions may be carried out by the same components or each may be effected by different elements. In most of what follows, discussion is limited to that portion of the window arrangement which affords the blast resistance.

The blast resistant window must be easy to close in times of emergency and must allow even the most inexperienced and panic-stricken user, rudely awakened from sleep, to quickly and effectively seal the protected space against explosions occurring outside the protected space. In addition, the blast resistant window must be easy to maintain, including periodic repainting. Furthermore, the blast resistant window should be positioned during the, hopefully, very long periods between use so as not to interfere with the normal functioning of the ordinary window and so as not to adversely affect the aesthetics of the building exterior or that of the interior of the protected space.

Typical presently known blast windows consist of a leaf made of steel plate, roughly one square meter in area and made up of steel plate 18 mm thick. The plate is hinged so as enable the blast window to be swung out of the way during normal periods and to be swung into place during emergencies. Because the leaf must withstand blasts occurring outside the protected space, the leaf is hinged so as to open to the outside of the building. Thus, in its normally open position, the window leaf is located outside the building at a position adjacent the window opening.

The presence of such unsightly steel plates on the outside of buildings, including private homes, apartment buildings, schools, offices, and the like presents an aesthetic problem of major proportions.

More importantly, the location of the blast window outside the building for periods of years can lead to its deterioration and malfunction. To prevent rusting and 'freezing' of the hinges, the window must periodically be painted and the hinges oiled. Maintenance of such windows, especially those located on floors higher than the ground floor, could be complicated and expensive. This could lead to improper or inadequate maintenance and could result in the failure of the blast window in time of need.

To overcome the problems associated with externally located hinged blast windows, a number of sliding blast windows have been developed. It has been heretofore believed that such a sliding window cannot slide into an internal pocket built into the wall. This belief arose for two reasons. First, it was believed that forming a pocket in the wall significantly weakens the wall, reducing its blast and fragment resistance in the area around the pocket. Second, it was not known how to design a blast window, which can fit into a pocket and seal against blasts and fragments and which can, when desired, be easily removed from the pocket for maintenance.

As a result, sliding blast windows have been designed wherein the window slides through an external pocket formed by mounting a removable cover plate a few centimeters outside of, and adjacent to, or flush with, the window opening. The cover plate must be sufficiently large to allow the blast widow to slide into the pocket and to store the sliding blast window during the very long periods when the blast window is not in use. While this solution appears technically more satisfactory than the hinged blast window, it, like the hinged window, must still be maintained from the outside. Furthermore, the externally sliding window is more expensive than the hinged window and presents a relatively large cover plate area which could have adverse effect on the aesthetics of the structure.

There is thus a widely recognized need for, and it would be highly desirable to have, a blast resistant window which will be readily and easily closed when needed, which will have sufficient strength to resist blasts occurring outside the protected space, which will not interfere with the operation of the ordinary window, and which will not adversely affect the aesthetics of either the interior of the protected space or the interior of the building. More specifically, it would be desirable to have a blast window which is slidable within an internal pocket in the wall, the presence of which will not weaken the wall, and which will be easily removable to facilitate maintenance.

SUMMARY OF THE INVENTION According to the present invention there is provided a blast resistant window arrangement for an exterior wall, comprising: an interior pocket formed in the wall laterally of the window opening; and a blast resistant leaf slidably mounted either to a stored position within the interior pocket or to an operative position aligned with the window opening; the leaf being of larger dimensions than the window opening to provide a peripheral surface abutting against the wall to resist blasts taking place outside of the building; the leaf being made of a plurality of plates each of smaller dimensions than the window opening fastened together by bolts which are removable to permit the leaf to be removed from the window opening for maintenance purposes.

According to further features in the described preferred embodiment, the leaf is made of two pairs of plates, each pair including two plates welded together with 103135 2 - 7 -one plate of each pair projecting laterally from a side of the other plate of the pair, such that each pair defines a main section of two-plate thickness having a lateral projection of one-plate thickness; the two main sections being fastened together by aligning their lateral projections over each other and passing the bolts through the aligned lateral projections.

According to further features in preferred embodiments of the invention described below, the leaf is made of steel and the wall in the vicinity of the pocket is reinforced, for example by reinforcing bars.

The present invention successfully addresses the shortcomings of the presently known blast window configurations by providing a blast window arrangement which effectively resists blasts or fragments but which is easy to maintain from the interior of the building and which places the leaf of the window in a pocket inthe interior o the wall where it remains out of sight of viewers from either the inside or the outside of the building during the very long periods between uses, and which may be easily disassembled from the inside of the building for purposes of maintenance .

BRIEF DESCRIPTION OF THE DRAWINGS The invention is herein described, by way of example only, with reference to the accompanying drawings, wherein: 103135/1 - 7a - FIG. 1 is a top cross sectional view of a blast resistant window arrangement according to the present invention; FIG. 2 is a side cross sectional view of a blast resistant window arrangement according to the present invention; FIG. 3 is a top cross sectional expanded view of a structure of the leaf of a blast resistant window arrangement according to the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention is of a blast resistant window for use with a window opening in an exterior wall. The window can be easily and rapidly deployed when needed in time of emergency. Once deployed, the window offers 8 effective blast and fragment resistance. During the long periods when the blast window is not in use, the window is stowed out of sight in an interior pocket of the wall adjoining the window opening. The window is designed to be easily removable from the interior of the building which greatly facilitates maintenance.

The principles and operation of devices according to the present invention can be better understood with reference to the drawings and the accompanying descriptions.

Referring now to the drawings, Figures 1 and 2 are top' and side cross sectional views, respectively, of a window arrangement according to the present invention. The exterior of the building is toward the top of Figure and to the right in Figure 2 . Shown in Figure 1 is a portion of an exterior wall 1 0 . Exterior wall 1 0 features a window opening 1 2 .

Wall 1 0 features a pocket 1 4 which opens toward one side of window opening 1 2 and which extends away from window opening 1 2 . The height, width and length of pocket 1 4 are such as to allow pocket 1 2 to slidably receive and store a leaf 1 6 . Leaf 1 6 is able to slide into and out of pocket 1 4 in one or more tracks 1 8 .

When deployed to cover window opening 1 2 the interior peripheral surfaces of leaf 1 6 abut against wall 1 0 . This aids in resisting blasts taking place outside of the building. One or more blocks 20 are preferably placed on the exterior window sill to prevent leaf 1 6 from displacing 9 in an outward direction from its deployed position.

To strengthen wall 10 in the vicinity of pocket 12, it is preferable to reinforce wall 10 to give it the ability to better withstand blasts and flying fragments. This may be accomplished in a number of ways. Preferably, the interior surfaces of pocket 12 are lined with steel plate 22 about 5 mm in thickness and anchored into wall 10 with the aid of shear studs 24.

Preferably also, wall 10 in the vicinity of pocket 12 includes reinforcing bars 26 which serve to further strengthen the pocket area.

The pocket area thus forms a composite section made up of two solid layers and an air gap between them. Such an arrangement shows high strength in dynamic response to blast and fragmentation. In order to penetrate the interior of the building, a fragment or a projectile must penetrate through the layers of steel bar reinforced concrete. Should a fragment or projectile mange to penetrate the outside layer of concrete, it will likely be deflected by the second layer of concrete without penetrating it. The inner layer of the pocket thus acts as a deflecting surface for any incoming fragments or projectiles .

Leaf 16 may be made of any suitable material which is capable of withstanding blasts and fragments. Preferably, leaf 16 is made of a metal or alloy, such as a suitable steel .

To facilitate maintenance, leaf 16 is preferably made w y nnec each other. One example of such an arrangement is shown in partial top cross sectional view in Figure 3. Here leaf 1 6 is made of two pairs of plates, designated 30 , 32 and 34 , 36 , respectively. The two plates of each pair are welded or otherwise permanently connected to each other and secured to the two plates of the other pair to form a monolithic structure. Thus, plates 30 , 32 are welded together to form a main section of two-plate thickness, and a lateral projection of only one-plate thickness, i.e., that of plate 32 alone. Plates 34 and 36 are welded together to form a main section of two-plate thickness and a lateral projection of one-plate thickness.

The two pairs of plates are detachably connected to each other, preferably through the use of bolts 38 which pass through the overlying lateral projections of one-plate thickness as shown in Figure 3.

Such a detachable attachment of the two portions of leaf 1 6 makes it possible to disassemble leaf 1 6 from the inside of the building for purposes of maintenance. When the two portions are connected to each other, as by bolts, leaf 1 6 cannot be removed from the window.

A window arrangement according to the present invention may further include means 17 for preventing gas from passing through the window, when the blast window is closed. Any convenient such means may be used, including sealing material disposed about the inner surface of the periphery of leaf 1 6. Preferably, the window arrangement features gas sealing means which are independent of, and which are located interiorly of leaf 1 6. Such a configuration avoids damage to the sealing means during a 11 blast which may slightly deform or reshape leaf 16.

While the invention has been described with respect to one preferred embodiment, it will be appreciated that many variations, modifications and other applications of the invention may be made.

Claims (7)

103135/3 WHAT IS CLAIMED IS:

1. A blast resistant window construction for an exterior wall of a building, comprising: an interior pocket formed in the wall laterally of said window opening; and a blast resistant leaf slidably mounted either to a stored position within said interior pocket or to an operative position aligned with said window opening; said leaf being of larger dimensions than said window opening to provide a peripheral surface abutting against said wall to resist blasts taking place outside of the building; said leaf being made of a plurality of plates each of smaller dimensions than said window opening fastened together by bolts which are removable to permit the leaf to be removed from the window opening for maintenance purposes.

2. The window construction as in Claim 1 , wherein said leaf is made of two pairs of plates, each pair including two plates welded together with one plate of each pair projecting laterally from a side of the other plate of the pair, such that each pair defines a main section of two-plate thickness having a lateral projection of one-plate thickness; the two leaf sections being fastened together by aligning their lateral projections over each other and passing said bolts through said aligned lateral projections. 103135/3 - 13 -

3. The window construction according to either of Claims 1 or 2, wherein said interior pocket includes tracks slidably receiving said leaf for movement either to said stored position within said interior pocket, or to said operative position aligned with said window opening. I*.

4. T s-r A window construction as in any one of Claims 1 to 3, wherein said plates are made of steel.

5. The window construction as in any one of Claims 1 to 4, wherein said pocket is lined with steel.

6. A window construction as in any one of Claims 1 to 5 wherein the wall is reinforced by reinforcing bars externally of and aligned with said window.

7. The window construction as in any one of Claims 1 to 6 further including sealing means located interiorly of said leaf for preventing gas from passing through said window opening when closed by said leaf.