13 L’ACCESSIBILITÀ è un tema relativamente recente e ha assunto una rilevanza sempre maggiore nel corso degli ultimi decenni. Gli edifici più vecchi, soprattutto nel caso di edifici storici o in centri storici, nati in epoche in cui l’attenzione all’accessibilità era scarsa o addirittura inesistente, spesso sono stati costruiti senza l’ascensore e frequentemente con spazi insufficienti a ospitarne uno. La struttura metallica è la soluzione che permette di rendere accessibile l’edificio migliorando la qualità della vita di quanti, a vario titolo, lo frequentano. La struttura metallica non trova una datazione precisa ma già nei primi disegni degli elevatori manuali inseriti al Colosseo vede la propria apparizione seppur con materiale e metodologie costruttive diverse. Oggi ha quasi perso la semplice funzione di supporto per l’impianto ascensore che va installato al proprio interno, diventando sempre più un elemento di arredamento del contesto ove va inserita. Le strutture metalliche per impianti elevatori sono tutte regolamentate dalla norma europea EN 1090 che ne definisce le caratteristiche e i requisiti minimi in base ai luoghi di installazione, la durata temporale e, cosa importantissima, la manutenzione regolare del manufatto sulla base delle indicazioni inserite nel manuale dal produttore. Abbiamo una prima suddivisione del prodotto a seconda che si tratti di installazione in ambiente interno o esterno e qui entra in gioco il trattamento specifico dei materiali. In ambiente esterno, peraltro come previsto dalla EN 1090, si deve includere il trattamento di zincatura superficiale al fine di proteggere il manufatto dalla possibile ossidazione. Chiaramente, ulteriori differenze sono date dalla tipoloACCESSIBILITY is a relatively recent topic and has become increasingly important over the past decades. Older buildings, especially in the case of historic buildings or in old town centres, born in times when attention to accessibility was scarce or even non-existent, were often built without a lift, and frequently with insufficient space to accommodate one. The metal shaft is the solution that makes the building accessible, improving the quality of life of those who, for various reasons, visit it. The metal shaft is not precisely dated, but already in the first drawings of the manual elevators inserted in the Colosseum it sees its appearance, albeit with different materials and construction methods. Today it has almost lost its simple function as a support for the lift system to be installed inside, becoming more and more a furnishing element of the context where it is to be inserted. The metal shafts for lift systems are all regulated by the European standard EN 1090 which defines their characteristics and minimum requirements based on the places of installation, the duration in time and, most importantly, the regular maintenance of the product based on the indications inserted in the manual by the manufacturer. There is an initial subdivision of the product according to whether it is to be installed indoors or outdoors, and this is where the specific treatment of materials comes into play. In an outdoor environment, as required by EN 1090, the surface galvanisation treatment must be included in order to protect the product from possible oxidation. Clearly, further differences are given by the type of covering that will provide for rainwater drainage rather than specific sealing to have a water-resistant product. A product installed outdoors also has important differences when it comes to technical calculation; apart from the calculation of the structure for the acting loads due to the system, one must consider, depending on the location, the loads due to the action of the wind rather than the snow load, obviously the seismic load if in a characteristic zone, as well as considering the specific temperatures depending on the area of installation. Here too, the anchoring system, which according to the standard will be indicated by the construction manager to the installer/manufacturer, is of fundamental importance to give the necessary stability to our structure. In the interior area, in addition to the installation loads, external loads come into play, which are fewer in number and do not interfere with the atmospheric environment, but are limited to the need to fix the structure. The metal shaft seems like a trivial task, but in reality it is not at all, as it is a container that requires a huge amount of knowledge about the lift products on the market, as well as up-to-date knowledge of the existing components. This is because the metal shaft are supplied with all the necessary predispositions to fix the system, and therefore the guide anchor brackets to the head beams and motor mounting predispositions when we are talking about electric traction, rather than the necessary predispositions to fix the floor doors or the portals that must comply with the specific regulations. Once the characteristics of
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