Explosion venting construction for buildings

Claim 1

A BUILDING HAVING A SIDE WALL PROVIDED WITH FRAME STRUCTURE DEFINING A GENERALLY RECTANGULAR OPENING THEREIN, A GENERALLY RECTANGULAR PANEL FORMED OF A FLEXIBLE, NONFRAGILE MATERIAL CLOSING SAID OPENING, THE INNER FACE OF THE PANEL BEING EXPOSED TO THE INTERIOR OF THE BUILDING, SAID PANEL COMPRISING TWO SPACED PLASTIC SHEETS MARGINALLY SECURED TOGETHER AROUND THEIR ENTIRE PERIPHERIES, SAID FRAME STRUCTURE HAVING MEANS FORMING A PAIR OF OUTWARDLY BOWED LEDGES ALONG TWO OPPOSITE SIDES OF THE OPENING, SAID OPENING BEING UNOBSTRUCTED IN AN OUTWARD DIRECTION AT SAID LEDGES, SAID FRAME STRUCTURE HAVING MEANS ALONG THE OTHER PAIR OF OPPOSITE EDGES OF THE OPENING FORMING GROOVES FOR RECEPTION OF OPPOSITE EDGE PORTIONS OF THE PANEL, SAID GROOVES BEING SPACED FROM ONE ANOTHER TO MAINTAIN SAID PANEL FLEXED INTO A BOWED CONTOUR IN AN OUTWARDLY CONVEX DIRECTION WITH ITS BOWED OPPOSITE EDGE PORTIONS SEATED AGAINST THE OUTER SURFACES OF SAID LEDGES AND WITH ITS OTHER PAIR OF OPPOSITE EDGES SEATED IN SAID GROOVES SUCH THAT UPON FURTHER BOWING OF THE PANEL IN AN OUTWARD DIRECTION IN RESPONSE TO THE APPLICATION OF PRESSURE TO THE INNER FACE OF THE PANEL SUCH AS MIGHT RESULT FROM AN EXPLOSIVE FORCE WITHIN THE BUILDING, SAID LAST MENTIONED EDGE PORTIONS OF THE PANEL, BY REASON OF SAID FURTHER FLEXING, ARE RETRACTED FROM SAID GROOVES TO PERMIT EJECTION OF THE PANEL AS A UNIT FROM THE WINDOW OPENING.