Fire Resistance in Externally Insulated Steel Plate Modules

Abstract: During recent years pre-fabricated lightweight elements, here used as 3D room modules, have become popular. There has also been an increased interest to place the fire protection outside of the room, in order to keep the production process simpler. Therefore, the only way to check the fire resistance is by using performance-based design. The combination of these two constrains creates the background for this work. A case study has been performed for lightweight 3D room modules constructed of steel cassettes, which are externally insulated. The modules will serve as student accommodations and have been analysed with respect to temperature development and bearing resistance. Following are the research questions raised at the beginning:

1. How does external insulation affect the fire- and steel temperature in the room and is it necessary to take this into account?
2. What is the modules’ resistance at elevated temperatures and how realistic can 3D effects be predicted by calculation?
3. Can the connections between wall and roof for self-supporting steel cassettes, be considered satisfactory at elevated temperature?
4. How well does simple calculation methods compare to advanced computer programs for these types of self-supporting lightweight modules?

Externally insulation of steel modules contributes to higher gas temperature in the room and therefore higher steel temperatures, which should be considered in performance-based design. Influence of a low degree of utilization on the bearing resistance, will be investigated by using two different types of methods for structural resistance (a simpler method and an advance method).

The standard fire curve ISO-834 and other fire scenarios are used to predict temperature development in the room.