This project is done by the need to contain the damage from a possible fire ignition in the phase of casting of aluminium alloys . The presence of Mg , fires that can reach develop a temperature of about 800 ° C. This study was carried out in particular for the area of casting.
The factory Agusta Westland site in the province of Benevento (Italy).
All the technical evaluation and economic evaluation is based on devising systems to rapid recovery of environments subject to possible fire. Focusing all too an easy supply of materials for the rapid restoration of the environment.
To be underlined that the problems due to triggering of fire, to the conditions referred to above, lead to considerable deterioration of the materials, for which it should take to isolate the booth with suitable materials, of which “ceramics” and / or refractory, but with considerably high costs which they would require, and still is, even though partial restoration of booths.
THE AIM OF PROJECT
The area of casting is divided into eight workstations, slaved by means of roller conveyors for the casting mold. Shuttle which proceeds to pour out the molten metal in the casting mold. The project aims to isolate the n.8 locations, in eight separate rooms of casting, as shown below.
In the n.8 booths, will be applied to the sliding doors, both in front side which in rear side of the booth. For to isolate the booths after having carried out the casting. It is assumed that the doors must allow the insertion and removal of the casting mold from the rear side. Interfacing with the shuttle for casting from the front side Moreover, for each booth must be provided to insert the extinguishing fire with powder.
TYPICAL ELEMENTS COMPOSING THE PROJECT
We have to create a system recovery and a rapid restoration of damaged items due to possible fire. Below an overview of some peculiarity which need to be the focus of the project. Frames, walls, roof and doors. The booths will be designed with a supporting frame in welded steel and painted. The frame will not be visible. It will be protected by shielding panels steel. The panels will be made of stainless steel, and fixed to the structure by means of longitudinal guides at labyrinth.
The same typology of panelling, is repeated for the roof and doors.
The system designed in this way: providing an air chamber between the inner and outer walls with a type similar to that applied to the roof and doors. Allow a normal flow of air due to the heat of the wall. Acting as a natural cooling system for the walls and for the supporting structure, without causing damage to the same support structures.
It is chosen a system of labyrinth seal between the modules of stainless steel panels, for the following reasons:
1) the high temperature that would destroy the classic joint seals;
2) will create the whirling movement of air that does not allow air to pass through it and it the advance of the fire;
3) simple module replacement of damaged panels.
For the sliding doors, the same will be realized in the typology in normal ventilation air, and will be assembled on automatic trolleys.
All guides and wheels, on which it bases the doors, should be made with graphite bushings.
OTHER ELEMENTS THAT MAKE UP THE SYSTEM
All the electromechanical elements that make up the booths and the enslavement systems, such as roller conveyors and suction for plant fumes casting. Must be designed in function immediate restoration.
For example, the assembly of the motorization of the roller tables will be redesigned for an immediate replacement. It’s provided with wired cable with connector, to be inserted in the appropriate socket protected.
The rule also applies to systems such as photocells and sensors.
All cable conduits must be of the ventilated type. Especially modular, with disconnectors for the interruption of the voltage in case of fire, and with systems and connections of bundle type. So as to perform a quick replacement of cables.
A system of this type can be applied in all those cases where the fire ignition could be quite frequent.
Our Team, taking as a sample the factory AGUSTA WESTLAND, has already established a calculation method for the application of the system and for air circulation.
It remains important that all systems will be modular, not only the structural part but also the electrical and electronics.
All this is transformed into a greater cost for design. That will never be as high as the cost of a system in ceramic booths or refractory, over to low cost of realization of the works.
It remains more convenient to restore of a modular booths in steel.