425 ILCS 68/20

(a) The truss construction emblem shall have a bright and reflective color or be made of reflective material. The shape of the emblem shall be an isosceles triangle and the size shall be 12 inches horizontally by 6 inches vertically. The following letters shall be printed on the emblem in a conspicuous size and color: "F" to signify a floor with truss construction; "R" to signify a roof with truss construction; and "F/R" to signify both a floor and roof with truss construction. (b) The emblem shall be permanently affixed to the left of the main entrance door at a height between 4 and 6 feet above the ground and shall be installed and maintained by the building owner.