Question: Just purchased and had installed a large (40") Heatilator Direct Vent Fireplace - corner installation. The next step was to install jack stands to support 1" plywood shelf 4" above horizontal pipe jacket. This is the min combustible clearance that the mfg recommends. All is fine. However, the amount of radiated heat that still continues to come off of the top of the pipe will cause the TV to malfunction. I would like to insulate the small 8" vertical rise, the 90 degree elbow and the short horizontal run to the thru-wall so that it radiates little or no heat. I went to a marine supply (thinking exhaust insulation), purchased 40' of 2" fiberglass wrap and a quart of a liquid material called water class .. and made in affect what looks like a cast on a broken arm. This seemed to cut the radiated heat down about 1/2, but it is still too hot. I am also worried about the fiberglass maybe being combustible. Am on the right track? -- is there a better idea? Should I just add another layer of fiberglass wrap or perhaps use another material? Answer: Insulating this pipe could be dangerous. The testing that is done assumes normal radiation off of the pipe as a cooling mechanism. If it were me, I'd try the following: Hang a piece of sheet metal on spacers about 1" below the plywood shelf in the area above the pipe. Also, if you can provide any ventilation where air can enter and/or leave the dead space area above the fireplace this would help.