Construction products detail

Chimneys for solid fuels serve to discharge flue gases from the combustion of solid fuels into the outside atmosphere via an outlet above roof level. They can also be used to discharge flue gases from the combustion of oil and gas.

During the combustion of solid fuels, soot may accumulate on the insides of the building components carrying the flue gas and may lead to soot fires with temperatures exceeding 1,000 °C. For this reason, chimneys for solid fuels must be designed to be resistant to soot fire.

The chimneys must be designed in such a way that no flue gases can escape into living areas and surrounding building components are not exposed to excessive temperatures. In cases where resistance-to-fire requirements exist in accordance with the Building Codes of the federal states (Landesbauordnungen), it must also be ensured that the fire cannot spread to other storeys.

Chimneys for solid fuels can be designed as system chimneys or as custom-built chimneys.

System chimneys are characterised by the fact that a single manufacturer is responsible for all of the different components included in the modular design. System chimneys can be designed with multiple walls; the term 'wall' referring to the flue liner carrying the flue gases, possibly an insulation product and/or an air/annular gap and an outer wall.

Custom-built chimneys are assembled at the place of use from components that are either covered by harmonised technical specifications (harmonised standard or ETA) or for which national technical approvals (abZ) have been granted. The individual components can originate from different manufacturers and bear either the CE marking in accordance with the relevant harmonised technical specification or the German national conformity mark (Ü-Zeichen) in accordance with the relevant abZ.

Regulatory framework

In this work area, DIBt grants:

• national technical approvals (abZ) for chimneys and/or parts of chimneys that are not covered by an ETA or the applicable harmonised standards for chimneys (system chimneys) or for parts of chimneys (custom-built chimneys);
• general construction technique permits (aBG) for the execution of chimneys not covered by the execution standard DIN 18160-1.

National technical approvals and general construction technique permits can be granted together in a single decision ('combined decision').

European Technical Assessments (ETAs) can also be issued for chimneys or parts of chimneys that are not (fully) covered by a harmonised standard. For construction products covered by an ETA, a general construction technique permit for the application may be pertinent.

The harmonised technical specifications for chimneys do currently not include requirements and assessment methods for resistance to fire. For this reason, DIBt issues verifications for this essential requirement.

DIBt also grants general construction technique permits for chimney applications in highly insulated buildings which are not covered by the European test standards with respect to the determination of the distance to combustible building materials.

Voluntary verification (e.g. DIBt evaluations) is currently recommended for dimensionally stable insulation products used in the execution of custom-built chimneys.

The technical rules to be observed in the execution of flue liners include:

• DIN EN 13384-1 – Chimneys – Thermal and fluid dynamic calculation methods – Part 1: Chimneys serving one heating combustion
• DIN EN 13384-2 – Chimneys – Thermal and fluid dynamic calculation methods – Part 2: Chimneys serving more than one heating appliance
• DIN V 18160-1 – Chimneys – Part 1: Design and performance

Please also note the relevant provisions of the federal states following MVV TB, Annex 8, Section 8.3 (2017/1) or Annex 14 (2019/1 and following).