Shutter

1. A shutter including:

an outer sheet of generally square or rectangular shape;

a non-combustible insulating panel of generally the same shape as the outer sheet; and

a frame,

the panel being positioned between the outer sheet and the frame so that the outer sheet overlies a first broad face of the panel and the frame is attached adjacent to a second broad face of the panel which is opposite the first face,

the outer sheet having edge regions and having a melting point of greater than or equal to about 840° C.,

the panel being operable to retard heat transmission from the first face thereof adjacent to the outer sheet to the second face opposite the first face, so that when the first face is exposed to a temperature of 730° C. for a period of 15 minutes, the temperature at the second face does not exceed 250° C.,

each of the outer sheet and the panel being secured to the frame, the frame including a lip, flange or channel within which the edge regions of the outer sheet are located and which allows the outer sheet to expand into the lip, flange or channel upon the temperature of the outer sheet increasing while maintaining the outer sheet overlying the first face of the panel, and the frame being substantially resistant to distortion up to a temperature of about 250° C.

2. The shutter according to claim 1 , the outer sheet being a metal sheet.

3. The shutter according to claim 2 , the outer sheet being a 0.5 mm thick steel sheet.

4. The shutter according to claim 1 , the panel being a plasterboard panel.

5. The shutter according to claim 4 , the plasterboard panel being between 10 to 16 mm thick.

6. The shutter according to claim 5 , the plasterboard panel being 13 mm thick.

7. The shutter according to according to claim 1 , the outer sheet and the insulating panel being fixed together by an adhesive.

8. The shutter according to claim 7 , the adhesive being selected to fail at a certain upper temperature.

9. The shutter according to claim 8 , the adhesive being selected to fail at about 200° C.

10. The shutter according to claim 1 , the lip, flange, or channel extending completely about a periphery of the outer sheet and the panel.

11. The shutter according to according to claim 1 , a seal being disposed between side edge regions of the shutter and facing surfaces of surrounds or frame portions of the window, door or opening within which the shutter is mounted.

12. The shutter according to claim 11 , the seal being an intumescent seal.

13. The shutter according to claim 1 , the shutter being a single shutter, a double shutter or a bi-fold shutter.

14. The shutter according to claim 1 , the lip, flange or channel being formed as a channel that includes a front lip, a rear lip and a base, wherein the front lip overlies the edge regions of the outer sheet.

15. The shutter according to claim 14 , the rear lip of the channel being fixed to a rear surface of the frame and the base of the channel extending about side edges of the frame, the panel and the outer sheet.

16. The shutter according to claim 1 , including a rear panel extending across the second face of the panel and the lip, flange or channel being formed as an extension of the rear panel which extends about side edges of the frame, the panel and the outer sheet and which forms a front lip that overlies the edge regions of the outer sheet.

17. The shutter according to claim 16 , the rear panel being spaced from the second face of the panel.

18. The shutter according to according to claim 1 , edge regions of the outer sheet being adhesively fixed to the portion of the lip, flange or channel that overlies the edge regions of the outer sheet.

19. The shutter according to according to claim 1 , the panel being fixed to the frame by adhesive.

20. The shutter according to according to claim 1 , edge regions of the panel being positioned within the lip, flange or channel.