I have a metal pole barn that i would like to install a woodstove in. I have placed the stove where i want it and have run the black single wall pipe up to the location i will exit the pipe through the metal wall. I installed a Clay Thimble that is surrounded by brick. This installation was done between the 4x4 posts. Can i run the same single wall pipe through the Clay Thimble and to the outside?. If so should i place fire proof insulation around the single wall pipe inside the Clay Thimble to reduce the heat transfer to the clay thimble and brick. If not, the inside diameter of the clay thimble is approx 7 3/4 inches. Will a double or triple wall pipe fit inside this clay thimble and if so would a double wall pipe be suitable to run as a outside chimney. I really do not want to remove the work that i have already done, my goal is to make it safe. The stove will not be used all the time and only will be used on occasion