LIGHTING FIXTURE ASSEMBLY SEALED AT OPPOSITE ENDS WITH DUST COVERS

A lighting fixture assembly includes a lighting fixture having a mounting member, a pair of end plates, an elongated lamp and an elongated lens, and a pair of dust covers fittable over opposite ends of the lighting fixture. Each end plate is mounted to one of the opposite end of the mounting member and is substantially comprised of a first material having a first coefficient of thermal expansion. The lamp is mounted adjacent to the mounting member and extends between the end plates and has opposite ends disposed adjacent to the end plates. The lens is mounted adjacent to the mounting member and extends between the end plates and has opposite ends disposed adjacent to the end plates. The lens together with the mounting member and end plates substantially encloses the lamp. The lens is substantially comprised of a second material having a second coefficient of thermal expansion different from the first coefficient of thermal expansion of the first material of the end plates such that when the lens and end plates are heated during illumination of the lamp a difference in expansion of the second material of the lens and the first material of the end plates occurs creating gaps between the opposite ends of the lens and end plates. Each dust cover securably fits over one of the end plates, one of the opposite ends of the mounting member and one of the opposite ends of the lens for covering the gaps therebetween and thereby sealing the assembly at the locations of the gaps to prevent foreign matter from entering the assembly through the gaps.