The Executive Design of the Technical Interfaces According to Performance Under Fire Loads

The study of the envelope systems examines the methodologies directed towards fulfilling the requirements with respect to the actions caused by fire loads, considering the contents related to both components and connections and fixing surfaces. The objective is to identify the containment and interruption criteria towards the development and propagation modes of the fire loads: on this basis, the study focuses on the technical interfaces with respect to the fire behaviour. The design study involves the specific sections of separation with respect to the fire compartments: this is to limit the propagation of a fire originating inside the building, the fire of a façade and its propagation, the fall of the façade elements. The attention is focused on non-load-bearing external façade systems, independent of the main elevation structures and, in general, fixed in projection with respect to the perimeter surfaces of the horizontal structures and transversal enclosures: for these systems, the application of a fire resistance strip is indicated in correspondence with each floor and each transversal wall, with a compartmentalization function. In the particular case of non-inspectable double envelope systems, supplemented by mechanical or natural air circulation in the cavity, it is examined the type consisting of the closed external wall and the type consisting of the open external wall. In addition, for the double envelope systems that can be inspected, the type consisting of the closed external wall, with the cavity interrupted by the fire-resistant inter-floor elements, the type consisting of the closed external wall, with the cavity with no horizontal interruptions, and the type consisting of the open external wall, for which the internal wall must have the similar fire resistance requirements to “simple façade” systems, are considered. The analysis implies the applications and interfaces for the main types of enclosures, specified by fire resistance classes, observing compliance through the methods based on tests, calculations and, finally, model solutions.