stainless steel and or 16 gauge cold rolled steel an insulating material may be disposed between the front and back panels of the chute door to reduce the amount of heat transferred from the back panel of the chute to the front panel when the back panel of the chute is exposed to fire and extreme temperatures chute door 22 also includes two chute side panels 32 mounted near the intersection of chute back 36 and chute side 34 chute side panels 32 are incorporated onto chute door 22 to guide materials through the chute opening when chute door 22 is in the open position referring now to fig1 chute side 34 includes a latch bolt 80 slidably positioned between a face plate 82 face plate 82 is mounted to chute side 34 by two plate screws 88 latch bolt 80 slidably moves into and out of bolt housing 84 latch bolt 80 is biased in the outward position by bolt spring 86 latch bolt 80 includes a tapered end 81 tapered end 81 is positioned such that it faces away from the inner surface of frame 24 the operation of the latch bolt with respect to the opening and closing of chute door 22 will be described below chute door 22 also includes a flange 40 attached to the outer edge of chute front.