A sheet-metal conduit connecting the boiler smoke boy with the base of the smokestack. It conveys the smoke and hot gases from the boiler to the stack and is usually made with double walls, with an air space between to prevent radiation of heat into adjacent spaces.
Icangci lesinyithi lombhobho weengcingo zombane ezidibanisa umsi webhoyila nesiseko setshimini. Lihambisa umsi nogesi oshushu ukusuka kwibhoyila ukuya kwitshimini kwaye yenziwe ngamadonga aphindwe kabini, ngesithuba somoya ngaphakathi ukunqanda ukunikeza ngobushushu kwizithuba ezimeleneyo.