A normal door is not sufficient to prevent ingress of water when floodwater rises above the level of the threshold. Although it would be possible to design a closure to be completely watertight, it could not be opened even if the level of floodwater were just above the threshold.

The present invention provides a closure assembly for preventing ingress of floodwater, comprising a horizontally movable closure for sealingly closing a surround, wherein the closure is divided into two or more horizontally movable closure members arranged one above the other so as to provide progressively higher closure against rising floodwater.

Preferably, the lowermost closure member is of such a height to enable it to be stepped over when closed.

Thus, with low floodwater levels, the lowest closure member may be kept closed to prevent floodwater entry but access is still possible by opening the upper closure member or members.

Preferably, the closure assembly has at least three closure members, but four, five, six or even more closure members are possible, depending on the height of the closure member, although from a practical point of view three to six closure members would probably be sufficient in most circumstances. Obviously, the greater the number of closure members the greater the cost.

Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, wherein: Fig. 1 is a perspective view of a closure assembly in the form of a door having six closure members in a closed position, Fig. 2 is a view similar to Fig. 1 with only the lowermost closure member in the closed position, Fig. 3 is a perspective view of a closure assembly in the form of a door having three closure members in a closed position, Fig. 4 is a view similar to Fig. 2 with the middle and upper closure members in an open position, Fig. 5 is a perspective view of a further embodiment of a closure assembly in which the door is shown, and Fig. 6 is a perspective view of the closure assembly of Fig. 5 in which the door is closed, but two closure members are open.

In Figs. 1 and 2 a closure assembly comprises a door 1 formed from six closure members or sub-doors 2 arranged one above the other in a surround in the form of a door frame 3. The sub-doors 2 are attached to the door frame 3 by hinges 4, which may be of any suitable kind, but the sub-doors 2 could be sliding if door 1 were constructed as a sliding door.

Suitable sealing means (not shown) must be provided between the door 1 and the door frame 3 to prevent ingress of water when the floodwater rises above the threshold.

Similarly, there should be suitable sealing means between each sub-door 2.

Obviously, each of the sub-doors 2 should itself prevent, or at least substantially hinder, the ingress of floodwater. For example, each sub-door 2 could be made from metal, plastics or other water impermeable material. In theory, the sub-doors 2 could be made from wood, but only certain timber would be suitable and the construction would have to be adapted to prevent ingress of water. It may be possible to provide sub-doors of standard timber construction with a skin of metal, plastics or other material to provide water impermeability.

The use of the door of Figs. 1 and 2 will be apparent. With low-level flooding, only the lowermost sub-door 21 need be closed, as shown in Fig. 2. Its height is such, that it can easily be stepped over and would be approximately 70 cm or less, e. g. approximately 35 cm. As the floodwater rises, successively higher sub-doors 2 will be closed. Even with the two lowermost sub-doors closed i. e. with a total height of about 70 cm, it should still be possible to use the door to go in and out of the building by stepping over the two lowermost sub-doors without too much difficulty. When higher sub-doors are closed, i. e. when the floodwater rises still further, it will be necessary to use other means, e. g. a short ladder, table or chair to go in and out of the building.

Thus, the closure assembly will keep out the floodwater while still allowing access until the floodwater reaches the uppermost sub-door.

Since most floodwater clears in a fairly short period, e. g. hours or days, it may not be essential to construct the closure members, e. g. the higher closure members, so that they are permanently water resistant. It could be sufficient, e. g. for reasons of cost, to ensure water impermeability for a limited period only. If floodwater is expected never to reach the top of the door, it would be sufficient, e. g. for reasons of cost, for only the lower closure members to be water impermeable, with the upper closure members of standard construction.

The closure assembly shown in Figs. 3 and 4 is similar to that shown in Figs. 1 and 2 except that there are only three closure members or sub-doors 2. The lowermost sub- door 2'is as shown in Figs. 1 and 2, whereas the upper sub-doors 211 and 2... have glass panels 5. Obviously, the glass panels 5 must have sufficient strength, e. g. thickness, to withstand water pressure at that height.

In Figs. 3 and 4 the lowermost sub-door 2 is shown the same height as in Figs. 1 and 2, i. e. about 35 cm. However, the lowermost sub-door could be higher, e. g. about 40 cm, 50 cm or even 60 cm. A sub-door of 70 cm can be still stepped over by tall people, but might present difficulties for shorter people or for the elderly.

In Figs. 5 and 6 a door 1 is mounted in a door frame 3 acting as a surround. As can be seen from Fig. 6, the door 1 has an outer frame 6 in which the lowermost part 21 of the door 1 acts as the lowermost sub-door, but is here integral with the outer frame 6. The sub-doors 21l and 2Ii thereabove are attached by hinges 4 to the outer frame 6, not to the door frame 3 as in Figs. 1 to 4.

During normal operation of the closure assembly the sub-doors 211 and 2"1 are fixed closed in the outer frame 6, so that the door 1 opens and closes as a whole. However, during flooding the outer frame 3 with the integral sub-door 21 is firmly fixed to the door frame 3, e. g. by locking, and access can still be obtained by opening sub-doors 2" and 2 il. If the water level rises further sub-door 211 may be fixed closed in the door frame 3.

If desired, instead of being integral with the outer frame 6, the lowermost sub-door 21 could also be hinged to the outer frame 6 in a similar manner to the sub-doors 211 and 2 thereabove.

Suitable resilient sealing means should be provided where necessary, ie between at least the lowermost closure members, and between the lowermost closure members and the surround of Figs. 1 to 4 and between the outer frame and the surround of Figs. 5 and 6, to provide"swimming pool water tightness"during flooding. If floodwater is not expected to reach the upper closure members, for reasons of cost, the sealing means may be dispensed with at this level. The sealing means could be formed from strips (solid or hollow) or rubber, plastics or any other suitable material.

The constructions described with reference to Figs. 1 to 6 may be used for French windows and patio doors or even for windows.

The closure assembly of the present invention may be installed in domestic buildings, e. g. houses or flats, communal buildings, e. g. schools, libraries or places of worship or industrial or agricultural buildings, or anywhere where there could be a threat from floodwater.

The closure assemblies described may be fitted at reasonable cost into an existing building to render it secure against floodwater, provided the rest of the building is reasonably secure against floodwater, particularly against floodwater that will recede fairly quickly.

For reasons of security, and also to withstand the pressure of floodwater, each of the closure members of the closure assembly could be fitted with a lock, latch or other suitable fastening means. Preferably, these can also be operated from the outside to allow opening of the closure members, and hence access to the building from the outside, during flooding.

Although the above embodiments have all been described in relation to preventing ingress of floodwater, the closure assembly in accordance with the invention could also be used to prevent ingress of snow, (eg during a snowstorm), mud, sludge or even sand (eg during a sandstorm), and the term"floodwater"is to be construed accordingly.