Patent ID: 8517809

Claim:
A fire resistant louver system comprising a plurality of overlapping aligned and superimposed louvers which allow airflow from one side of the system to the other, said louvers each having a pair of legs, each leg having first and second opposed surfaces respectively spaced from the legs of the louvers immediately adjacent to them, the legs in each louver diverging from each other at an acute angle defining an apex between them to form circuitous passages between the adjacent leg surfaces for said air flow along the leg surfaces and between the spaced legs, and strips of intumescent material mounted on at least the entirety of the first surface of one leg of each of said louvers on alternate louvers on opposite sides of the apexes between the legs of the louver system whereby when said system is subjected to heat above a predetermined temperature said intumescent material expands to contact the second surface of the louver leg opposite the intumescent material to fill the spaces between said legs to close said circuitous passages.