Inspection of Fire Dampers

Due to its very good technical properties asbestos was used in fire dampers until the end of the 1980s.

Apart from the damper blades and – depending on the manufacturer – other construction elements, mainly the stop gaskets consisted of asbestos-containing foamed material (product name “Litaflex”).

Asbestos-containing fire dampers are known from the following manufacturers, among other things:

Typical mounting conditions of fire dampers

Typical mounting conditions of fire dampers

Overview of the most important dates:

  • at the latest until 30 September 1984 (depending on the manufacturer), TROX until June 1981:
    asbestos-containing damper blades, stop gaskets and other construction elements
  • until 31 July 1988 (TROX, SCHAKO), until mid August 1988 (WILDEBOER):
    asbestos-containing stop gaskets (“Litaflex”) and sporadically fiber cement
  • at the latest from the beginning of 1989 (for all manufacturers): asbestos-free

All these construction elements are “friable asbestos products” in terms of TRGS 519 (“Technische Regeln für Gefahrstoffe: Asbest – Abbruch-, Sanierungs- oder Instandhaltungsarbeiten“). Since the late 1970s, the law requires all owners of existing buildings to obtain an expert assessment with regard to a possible need for remediation for asbestos-containing building materials.

So far this has been performed on the basis of the asbestos guideline (“Richtlinien für die Bewertung und Sanierung schwach gebundener Asbestprodukte in Gebäuden”) which, depending on the assessment results, requires immediate reconstruction or regular reassessment depending on the condition and use of the building.

Old fire damper with flap and gasket containing asbestos

New fire damper with asbestos-free seal

When it was introduced in 1989, the asbestos guideline specified a general classification of fire dampers containing asbestos (without individual inspection) in priority level III (“long-term reassessment necessary”, i.e. within a maximum of 5 years) without any direct need for remediation. The reason for this was that in normal operation it could be assumed that the damper blades and seals were not damaged and that, according to the assessment at the time, they hardly released any fibers.

Nowadays, about 500,000 of the old asbestos-containing fire dampers are still in operation. After a long period of operation, many of them show clear symptoms of aging (especially at the stop gaskets).

Often, the asbestos foam of the stop gaskets already decomposes due to aging processes and is further destroyed each time the damper is triggered. In addition to the possibly limited fire protection effectiveness, measurements have now shown that fire dampers damaged in this way can release asbestos fibers into the ventilation system when they are triggered (the blade hits the gasket). Damage to a damper blade containing asbestos can also contribute to the release of asbestos fibers. Currently, some companies therefore refuse to perform maintenance or testing on asbestos-containing fire dampers. As a result, some building owners are skipping testing/maintenance work and thus failing to fulfill their obligations under the law.

Severe damaged gasket (“Litaflex)” containing asbestos
with adhesions on the flap

 Heavily damaged asbestos-containing stop gaskets (“Litaflex”)

An evaluation of fire dampers with regard to their need for reconstruction (immediate reconstruction in the case of severe damage or periodical re-evaluation in the case of components with little or no damage) is therefore no longer appropriate in order to prevent a possible risk to users. In the current “LV 45 Guidelines on the Ordinance on Hazardous Substances” of the LASI (Länderausschuss für Arbeitsschutz und Sicherheitstechnik – State Committee for Occupational Safety and Safety Technology) of October 2018, the new knowledge about the fiber release potential, especially during inspection/maintenance work, is already taken into account.

Accordingly, the maintenance work on dampers containing asbestos is subject to an expert knowledge and notification requirement. In addition, clearance measurements are prescribed if asbestos fibers can enter the rooms connected to the ventilation system through the outlets of the ventilation system during inspections.
In addition, the protective measures listed in the Hazardous Substances Ordinance for asbestos exposure (multi-chamber airlocks with negative pressure maintenance, etc.), which correspond to the specifications of TRGS 519 for “Demolition and Restoration Work on Weakly Bound Asbestos Products” (Section 14), must also be taken into account.

Due to the current legal requirements, the overall cost of operating and maintaining (functional testing) fire dampers containing asbestos has increased significantly, so that in addition to the fire protection aspects, a reconstruction is now also recommended from an economic point of view.

Person-related measurements during maintenance work at fire dampers

The current state of the art is an individual assessment of the fire dampers with regard to their condition by an asbestos expert and the grading of the fire dampers into damage categories depending on the assumed risk of fiber release.

For this purpose, the Gesamtverband Schadstoffsanierung (GVSS) published in March 2021 the „Handlungsempfehlungen zum Umgang mit asbesthaltigen Brandschutzklappen“ (Recommendations for the handling of fire dampers containing asbestos) prepared by the working group “Asbesthaltige Brandschutzklappen” (Fire dampers containing asbestos), in which the LGA-IUA is also involved. The publication summarizes the current state of knowledge in the handling of fire dampers containing asbestos. It is aimed at operators and building owners, construction experts and specialist companies in the fields of fire protection and technical building equipment. The aim is to provide recommendations for the safe handling of fire dampers containing asbestos from an expert’s point of view, as long as there are no corresponding specifications from the state and/or the professional associations.

Since it is often not possible to replace all the fire dampers in a building at the same time for organizational and financial reasons, the “prioritization” by the asbestos expert with recommendation of the sequence of demolition or reconstruction introduced with the „Handlungsempfehlungen zum Umgang mit asbesthaltigen Brandschutzklappen“ (Recommendations for the handling of fire dampers containing asbestos) is useful. This also serves as a basis for coordination between the building owner, building authorities and fire protection experts.

During the inspection, the asbestos expert also documents the environment of the fire damper (access, room dimensions, etc.) and analyzes it for the presence of other materials suspected of containing asbestos (fire protection boards, mortar, fillers, flange gaskets, etc.) and other components containing harmful substances (e.g. old mineral wool). These aspects must also be taken into consideration during a demolition or reconstruction.

Our services to you include:

  • Expert assessment of fire dampers with analysis for evidence of asbestos
  • Assessment of the current condition and grading into damage categories / priority levels according to the GVSS recommendations for action
  • Technical investigation in the surrounding area of the fire dampers (collection and analysis of material samples)
  • Contaminant register
  • Renovation and disposal concepts
  • Occupational safety concepts
  • Bidding documents
  • Project management, remediation and dismantling supervision

The General Association of Hazardous Material Remediation (Gesamtverband Schadstoffsanierung, GVSS) has certified us as “Remediation experts for surveying and planning” for the remediation of buildings and plants impacted with contaminants.

Moreover the LGA-IUA is qualified as “Examination Center for Contaminated Building Materials and Construction Waste” to perform external quality controls and take on tasks as head technical expert.

The German Demolition Association (Deutscher Abbruchverband, DA) has officially recognized Dr. Kisskalt as an “expert advisor” for the categories “general demolition”, “hazardous building materials” and “waste management”.

Here you will find our summary on the subject of “fire dampers containing asbestos”.

Bernd Malkmus
Diplom Geologist

Phone: +49 911 12076 112
Telefax: +49 911 12076 110
Mobile: +49 151 16 76 50 43

Carmen Weiblen
Diplom Geographer

Phone: +49 911 12076 115
Telefax: +49 911 12076 110
Mobile: +49 160 53 72 365

LGA Institut für Umweltgeologie und Altlasten GmbH

Christian-Hessel-Str. 1
D-90427 Nürnberg

Phone:  +49 911 12076 100
Telefax:  +49 911 12076 110


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