I have a pool heater with a 6" vent pipe that is routed through a wood picket fence. I am concerned that the heat from the pipe will damage the wood and potentially be a fire hazard. Is there a recommended insulation material that I can use around the hole in the fence that the pipe passes through to insulate the wood? I'm thinking of something like a pool noodle that I can slip over the edges of the fence boards, but made of a heat resistant ceramic/silicone material. Any suggestions?