Double wall chimney systems are usually used for fireplaces, heating, steam and hot oil boilers and for process or hood systems, through which high temperature gases flow. The system is double walled and mono block;rock wool insulation is inserted between the walls. It has low thermal conductivity, since the heat of the chimney gas is not considerably transferred to the environment, the chimney efficiency is high. It is manufactured with continuous TIG or PLASMA welding. The chimney connections are male-female joints and tightened with a stainless steel clamp from outside. The system is designed to compensate the expansion of the inner wall due to high chimney gas temperatures.

Double Wall Chimney Types are produced as RTKD, RTKD Mono, RTKA, RTKAS and RTKNAS series.