Intumescent coating after the short-term weathering (left) and during the fire test (right)
Source: BAM
Certain environmental and climatic factors cause intumescent coatings to age. To achieve the required thermal protection in the case of fire, the products must maintain their durability throughout the intended working life. However, the ageing process is complex and not fully understood. Established durability assessment procedures target a working life of 10 years. For a longer period, the procedure and the specifications to justify the durability are not specified.
In the completed IGF project No. 20470N (Research Association: Deutscher Ausschuss für Stahlbau DASt), BAM collaborated with the Institute for Steel Construction of the Leibniz Universität Hannover to assess the ageing behaviour of intumescent coatings for the fire protection of steel members. The research not only summarises existing knowledge on the ageing of intumescent coatings, but also comprises an extensive experimental testing programme.
Two types of intumescent coatings were tested by various demanding weathering approaches. The aged coatings were analysed by thermos-analytical methods and fire tests. Moreover, formulations with a reduced amount of functionally relevant components were investigated to gain insight into the associated effects. With the help of the results of an extensive literature research, experimental investigations, and enhancements of numerical models, a proposal for a reliable test concept for the proof of a working life of intumescent coatings of more than 10 years was derived. Recommendations are based on short-term weathering tests and a combination of verifications. This approach has already been adopted by the Deutschen Institut für Bautechnik (DIBt) and was used as the basis for extending the working life of intumescent coatings to 25 years. The main findings of the research project were published in the Fire Safety Journal article: “Durability of intumescent coatings and recommendations for test concepts for a working life of more than 10 years”.
Durability of intumescent coatings and recommendations for test concepts for a working life of more than 10 years
Dr.-Ing. Dustin Häßler, Dr.-Ing. Maximilian, Dr.-Ing. Lars-Hendrik Daus, Dr.-Ing. Sascha Hothan, Prof. Dr.-Ing. Peter Schaumann, Prof. Dr. rer. nat. habil. Bernhard Schartel
Fire Safety Journal, 2024