Balanced flue systems

Balanced flue systems are room-sealed appliances, meaning that instead of using the air of the heating room as combustion air, outside air is supplied to the appliance. Balanced flue systems convey combustion air from the inlet above roof level to several heating appliances which are operated independently of one another. The flue gases are discharged via a separate duct above roof level. The flue liner and air supply duct can be arranged concentrically (duct within a duct with annular gap) or side by side.

Soot-fire-resistant balanced flue systems are also known as room-sealed chimneys and are designed for connection of heating appliances for solid fuels.

In accordance with the legal provisions of the federal states following Section 7(10) of the Model Firing System Ordinance (MFeuV), room-sealed heating appliances may only be connected to the balanced flue system if the construction technique ensures that they are suitable for this mode of operation.

These firing systems meet stricter tightness requirements and may therefore also be operated in highly insulated buildings, including in combined operation with ventilation systems.

Regulatory framework

In this work area, DIBt grants:

  • national technical approvals (abZ) for balanced flue systems and/or parts of balanced flue systems that are not covered by a European Technical Assessment 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 balanced flue systems 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 balanced flue systems or parts of balanced flue systems 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.

For dimensionally stable insulation products used in the execution of custom-built chimneys, voluntary verification (e.g. DIBt evaluations) is currently recommended if the application temperature limit for the insulation product lies above the flue gas temperature of the flue liners.

The technical rules to be observed in the execution of chimneys 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).

Technical rules

Muster-Feuerungsverordnung (MFeuV)

Stand: September 2007, geändert durch Beschluss der Fachkommission Bauaufsicht vom 28.01.2016 und 27.09.2017; Fachkommission Bauaufsicht der Bauministerkonferenz

Application forms

National procedure

A national technical approval (abZ) and/or oder general construction technique permit (aBG) is granted upon application (see Model Building Code (MBO), Sections 16a(2) and18(2) and (4)). This also applies to amendments and supplements to, or renewals of existing approvals and/or construction technique permits.

No formal requirements apply. The following information is needed: name and address of the applicant, description of the product and/or construction technique and its field of use or application, type of decision required (new decision, amendment or supplement to, or renewal of, an existing decision).

Please feel free to use the template below.

Application for a national technical approval and/or construction technique permit (3 pages)

Version: January 2018; Application form

Application for amendment / supplementation / renewal of a national technical approval and/or construction technique permit (4 pages)

Version: January 2018; Application form

Guideline: How to provide drawings for national technical approvals and general construction technique permits (5 pages)

Version: July 2017

European Technical Assessment (ETA)

To start the ETA procedure, please submit the form below. We will then check if the prerequisites for issuing an ETA are met, i.e., in particular, if the product is not fully covered by an existing harmonised standard. If the prerequisites are met, we will check whether a European Assessment Document (EAD) covering the requested assessment scope already exists or still needs to be developed. If an EAD needs to be developed or amended, a complete technical file needs to be established before the procedure can begin.

Form for requesting a European Technical Assessment (ETA) (2 pages)

Last updated: 16 June 2022

Voluntary evaluations of fitness for use

Where the relevant harmonised standard is incomplete, economic actors can provide product performance information on a voluntary basis. DIBt offers independent validation and confirmation of such additional performance information in the form of a voluntary evaluation of fitness for use.

Order for an evaluation (4 pages)

of fitness for use of construction products

  • abZ/aBG
  • Z = new decision | E = supplement | Ä = amendment | V = renewal | G = valid until
    Subject concerned Applicant Decision no. Validity
    from / to
    Luft-Abgas-System "BOSCH" T120 P1 W 2 O00 LA90

    Bosch Thermotechnik GmbH

    Junkersstraße 20-24

    73249 Wernau

    Z-7.5-3059 Z: 06.05.2022
    G: 01.04.2023
    Bauarten von Luft-Abgas-Systemen

    Centrotherm Systemtechnik GmbH

    Am Patbergschen Dorn 9

    59929 Brilon

    Z-7.5-3122 Z: 20.01.2021
    G: 20.01.2026
    Bauarten von Luft-Abgas-Systemen

    Skoberne GmbH

    Ostendstraße 1

    64319 Pfungstadt

    Z-7.5-3256 Z: 07.10.2019
    G: 07.10.2024
    Bauarten zur Montage von Luft-Abgas-Systemen

    M&G Group B.V.

    Dr. A.F. Philipsweg 41

    9400 AB ASSEN


    Z-7.5-3321 Z: 29.04.2022
    G: 29.04.2027
    Bauarten von Luft-Abgas-Systemen

    ATEC GmbH & Co. KG


    Liliencronstr. 55

    21629 Neu Wulmstorf

    Z-7.5-3356 Z: 04.03.2019
    G: 04.03.2024
    Luft Abgas-System "eka complex P"

    eka-edelstahlkamine gmbh

    Robert-Bosch-Straße 4

    95369 Untersteinach

    Z-7.5-3473 Z: 21.04.2020
    G: 21.04.2025
    Luft-Abgas-System "almeva LBS PPeasy" T120 H1 W 2 O00 LA90

    Almeva AG

    Industriestraße 6



    Z-7.5-3497 Z: 05.02.2021
    G: 05.05.2026
    Bauarten von Luft-Abgas-Systemen mit Innenrohren oder Systemabgasanlagen aus Kunststoff

    Jeremias Abgastechnik GmbH

    Opfenrieder Straße 12

    91717 Wassertrüdingen

    Z-7.5-3548 Z: 18.05.2022
    G: 18.05.2027

Ronny Schmidt
Head of Section – Combustion Appliances, Chimneys, Building Services

Phone +49 30 78730-473
Email rsi(at)dibt(.)de

Legal reference documents

Testing, certification, inspection