Fucich LLC has been replacing the round exhaust AO42 duct for GE in several combined cycle plants.

We remove the exhaust flex seal and the aft expansion joint then we cut the existing round exhaust duct into four pieces and fly those out.

The new round exhaust duct comes in four linear sections. We rig the bottom piece in first and set it on temporary supports. We rig the two side pieces in place and align them to the bottom piece, tack them together and set that assembly on the existing supports. We rig the top piece in and fit it to the rest of the assembly then make the four outside linear welds. We insulate the inside joints, install new rolled liner sheets over the insulation and weld washers to studs to hold the liners in place. We install new exhaust flex seal components and a new aft expansion joint.