If the exhaust system is operated dry, the temperature on the inner surface of the exhaust pipe is planned to be above the dew point of the exhaust gas when the system is in operation. This means that no condensate precipitates in the exhaust pipe when operated properly. The system does not have to be condensate-resistant.
See also encyclopedia article Exhaust system, condensate resistance classes according to DIN V 18160-1
Source: bauwion
