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Flue gas heat exchangers

Flue gas heat exchangers transfer the thermal energy from the heating appliance flue gas to the heating water. This increases the efficiency of the heating system.

Regulatory framework

In this work area, DIBt grants:

  • national technical approvals (abZ) for flue gas heat exchangers that are not covered by the applicable harmonised standards or a European Technical Assessment;
  • general construction technique permits (aBG) for the design and execution of the corresponding applications.

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 flue gas heat exchangers 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 technical rules to be observed for the application of flue gas heat exchangers include:

  • DIN EN 12828 – Heating systems in buildings – Design for water-based heating systems
  • 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

Please also note the relevant provisions of the federal states following MVV TB, Section B 3.2.1.31.

For the assessment of the above-mentioned construction products and techniques within the framework of the national procedures, DIBt prepares application-specific test plans. DIBt approval principles and preliminary test programmes form the basis for this.

The approval principles and preliminary test programmes are no conclusive technical rules, but rather compilations helping to speed up the procedure. They are not published, but are made available to the applicants during the approval or permit procedure.

The following preliminary test programme has been prepared up to now:

Preliminary test programme for flue gas heat exchangers for completing or retrofitting of firing systems with non-room-sealed heating appliances (Vorläufiges Prüfprogramm für Abgaswärmeübertrager zur Komplettierung von /oder zum nachträglichen Einbau in Feuerungsanlagen mit raumluftabhängigen Feuerstätten)

National procedure

To prepare an abZ/aBG for your construction product, we need an application from you. We recommend that you contact us prior to doing so. Feel free to send us your enquiry informally via email to dibt(at)dibt(.)de or to the competent technical contact listed in the top right.

For a first assessment, please send us the following information:

  • Description of the construction product and its intended field of use
    • e.g. material, configuration, number of sizes, variants, dimensions
    • e.g. use in walls, ceilings, interior construction, building services
  • Description of the construction technique and its field of application
    • e.g. design of walls, ceilings, elements, etc., and interaction of components
    • e.g. application in foundation engineering, reinforced concrete construction, building insulation; as load-bearing or non-load-bearing component; under static and quasi-static loading; fire exposure; other environmental exposures
  • Information regarding impact on regulatory concerns
    • in particular structural integrity, fire protection, health and environment protection, sound insulation as well as thermal performance
  • Explanation of need for an abZ/aBG
  • Contact details
    • preferably email address and/or telephone number, as well as name, organisation/company, and postal address

We will then contact you to clarify the next steps.

If you already hold a DIBt approval and/or construction technique permit and wish to apply for an amendment, supplement, or renewal, please use the form provided below.

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.

abZ+aBG

Z
new decision
E
supplement
Ä
amendment
V
renewal
G
valid until
Subject concerned Applicant Decision no. Validity
from / to
Abgaswärmeübertrager "ÖKO-Carbonizer" EISN GmbH Am Wall 9 89434 Blindheim Z-43.31-200 Z: 10.10.2023
V: 31.05.2024
G: 30.05.2029
Abgaswärmeübertrager mit der Bezeichnung "Juraflux" Metallbau Mayr GmbH Ottinger Ring 17 86704 Tagmersheim Z-43.31-220 Z: 02.01.2024
G: 02.01.2029
Abgaswärmeübertrager mit den Bezeichnungen "GPH AK 28", "GPH AK 50" und "GPH AK 75" sowie "GPH HP 28", "GPH HP 50" und "GPH HP 75" ATEC GmbH & Co. KG Abgastechnologie Liliencronstr. 55 21629 Neu Wulmstorf Z-43.31-222 Z: 14.05.2019
V: 31.05.2024
G: 19.06.2029
Abgaswärmeübertrager mit den Bezeichnungen "AWT - S1, AWT - S2" Ulrich Bachmann Innovative Klima- & Lufttechnik Hauptstraße 5 08237 Steinberg/OT Rothenkirchen Z-43.31-261 Z: 09.11.2021
G: 09.11.2026
Abgaswärmeübertrager mit der Bezeichnung "AWT - S3" Ulrich Bachmann Innovative Klima- & Lufttechnik Hauptstraße 5 08237 Steinberg/OT Rothenkirchen Z-43.31-262 Z: 10.11.2021
G: 10.11.2026
Abgaswärmeübertrager mit den Bezeichnungen "AWT" und "AWT-BP" Karl Schräder Nachf. Hemsack 11-13 59174 Kamen Z-43.31-300 Z: 27.11.2017
V: 28.11.2022
G: 28.11.2027
Abgaswärmeübertrager "TurbuFlex-System" Dipl.-Ing. Klaus Schmitt Konstruktion Abgaswärmetauschersysteme Siegenstraße 132a 44359 Dortmund Z-43.31-337 Z: 02.12.2022
G: 07.12.2027
Wärmeübertragerbausatz für Speicherfeuerstätten der Firma Tulikivi Oy mit der Bezeichnung "W10" Tulikivi Oyj Joensuuntie 1226B 83900 JUUKA FINNLAND Z-43.31-442 Z: 07.03.2024
G: 07.03.2029
Abgaswärmeübertrager mit der Bezeichnung "TurbuFlexS" K. Schräder Nachf. Inh. K.-H. Schräder Hemsack 11-13 59174 Kamen Z-43.31-462 Z: 16.07.2024
G: 14.08.2029
Abgaswärmeübertrager mit den Bezeichnungen "TurbuFlexS-600 Condens" und "TurbuFlexS-1200 Condens" für den Kondensationsbetrieb Karl Schräder Nachf. Hemsack 11-13 59174 Kamen Z-43.31-477 Z: 09.11.2021
G: 09.11.2026