Single-shell external chimney made of metal without an insulating layer. It is a simple exhaust pipe, usually made of high-quality stainless steel, which is routed outside the building on the outer wall or free-standing over the roof. Single-walled chimneys are mainly used in the industrial sector in Germany, usually with very high exhaust gas temperatures, both for under- and overpressure operation. In addition, they serve as a chimney for houses with an emergency generator or solid fuel fireplace, which is then only used in emergencies, but under no circumstances in continuous operation.
Due to the lack of an insulating layer, rapid cooling of the exhaust gases is favored, which reduces the draught effect and causes the precipitation of condensate if exhaust gas temperatures are not sufficiently high. A single-walled outdoor chimney is therefore fundamentally unsuitable for modern fireplaces in the domestic sector. Chimney systems generally require building authority approval.
Source: bauwion
