FromAWV (Holland, OH), the TFD-75 heavy-duty fire damper is a flanged frame, airfoil-bladed damper that has been stringently tested to meet British Standard BS476, Part 20 requirements as well as the operability requirements of NFPA 130. The standard damper is offered in an 8 in. Deep channel frame, and is certified with frames up to 12 in. Deep. The unit is available with silicone or stainless steel seals, stainless steel sleeve bearings, 3/16 in. Linkage arms, 1/4 in. Linkage bars, and UL555S Class I and Class II leakage options.