Ok, need a little advice. I'm building a home that the owner wants a gas insert that uses 4.5/7.5 twist lock secure vent installed in the basement. My only vent option is to go 4 foot vertical then elbow through block then 8 foot horizontal and terminate out the side of the brick porch. My problem is the horizontal run will be under ground under a concrete porch, to keep the vent pipe away from moisture dirt I have some 8inch pvc sewer pipe I can use to run it inside, any thoughts? Will the exterior of this exhaust pipe get too hot?