Any suggestions on how to fireblock around flexible ducting? Here is my situation. My basement has it's own forced air heatpump system. The HVAC contractor ran a number of small diameter (6-8") flexible ducts to each of the registers. Since the ducts run perpendicular to the ceiling joist, they are hung with straps below the joists. I am going to put a suspended ceiling just below the ducts. I framed a utility room around the air handler. The ducts are perpendicular to the utility room wall and run just under the top plate. I put blocking between the studs just below the ducts. I can drywall up to the blocking beneath the duct which will be the approximate height of the ceiling. My understanding is that I need fireblocking between the utility room and the space above the syspended ceiling. I need to figure out how to fill the voids between the round ducts and the square opening between the studs and blocking. Since the flex ducts crush and move easily, I am not sure what would work best. Thanks.

i bought my house a year ago. The previous owner had sheetrocked half the basement but he did not box any pipes, so they are beneath the sheetrocked ceiling. The pipe that run along the outer side I am planning on having a plumber move over so that i only have to box out maybe 6 inches instead of a foot. There is one pipe that runs parellel with the joists.Iservicing castiron baseboard in hallway above) if i cut out the sheetrock above and have the plumber put the pipe between the joists would I have to fabricate a 16 inch access across the basement or just a couple of access panels? If there was a leak and i sheetrocked it after moving pipe up of course i would have to re-spackle and paint cieling. Or would it be best to use sanded plywood and screw in with white screws in attempt to blend in?? boxing in pipes on side of basementthat run perpendicular is it best to sheetrock or frame out with pine and paint?? It will end up being maybe 3 inches down and four inches out to conceal pipe.