Optimisation of intumescent coatings
Use of advanced calculation methods
The aim of using parametric finite element models is primarily to eliminate the need for fire protection measures, depending on the application in combination with a natural fire simulation, as described in this article:
However, the models can also be used to determine the critical temperatures of various structural components - for example, steel columns as well as steel girders with or without reinforced concrete slab.
Designing the thickness by determining the critical temperature
The design of the thickness of intumescent fire coatings is carried out with the help of this critical temperature. The higher the critical temperature of the individual component, considering its utilisation due to the load and its boundary conditions, the lower the thickness of the fire protection coating can be designed. The critical temperature can be determined according to the simplified methods of EN 1993-1-2 by tables and nomograms.
Optimised coating using engineering methods
However, determining the same with the help of finite element models has decisive advantages. On the one hand, due to the generality of extended calculation methods, no restrictions on certain boundary conditions, such as constraint freedom of the component, need to be considered. On the other hand, the potential for smaller layer thicknesses can be used than by simplified methods.
For a reference example with a column HEB 340 with requirement R60 from the steeldoc 05/2017 of the Swiss Steel Construction Centre, the thickness of 503 μm according to the simplified method can be optimised again to 405 μm with extended calculation methods for an exemplarily selected product of an intumescent fire protection coating.