PLAXIL 8 | Studio Valle Architetti Associati

Plaxil 8 is an industrial building housing a fully automated MDF (Medium Density Fiberboard) manufacturing line. The line consists of a fiber sorting and mat formation section, a continuous hot press section and an unloading and stacking section. This plant replaces the previous Plaxil 4 and Plaxil 5 press lines, retaining however their existing defibrators and warehouses. The building covers an area of about 8500 square metres within the Osoppo production site of the Fantoni group. It is situated among other buildings north of the Plaxil 5 “Cathedral” building, originally designed by Gino Valle in 1985. The building is 300 m long and 28 m wide. Its west side is over 50 m high, while the rest of the structure has an average height of 14.50 m. It is the largest press in Europe and the second largest in the World for the production of MDF boards, which are used for the manufacture of furniture, doors, interior panelling and soundabsorbing materials. The manufacturing plant housed in the building consists of three main areas: - The mat formation area, where the dried fiber and resin mixture enters the line and is conveyed through gravity sorters, cyclones, bunkers and forming heads by means of a complex system of pipes and blowers. In this section, stacks and cyclones reach heights in excess of 50 metres. - The continuous hot press, which is about 75 metres long and weighs over 3000 tonnes, presses the mat to the required thickness, while heating it to a temperature in the region of 240 °C by means of a heat transfer fluid system to cure the thermosetting resin mixed with the wood fiber and transform the mat into a board. This line is housed in the linear section of the building, which has a constant height of 14.50 metres. - The unloading line, where the boards are first cut to size using a continuous-cycle diagonal cutting machine, and then cooled by natural convection on two large star-shaped coolers. The boards are then stacked and directed to the automated warehouses by means of a 400 meter long overhead conveyor line or an inductiondriven ground conveyor line. The unloading line is located inside the 14.50 metre high section also. The conveyor lines are independent structures, joining the Plaxil 8 building to the other existing buildings across the separating spaces. The same structure supports both the building and the machinery. The challenge of the design was in specifying a load-bearing frame shared by both the plant and the architecture with overlapping erection times. In the resulting solution we have opted for a 28 metre wide, single span linear structure supported by lattice trusses, an internal concrete building housing the service areas, and a large metal frame supporting the various levels of the mat formation plant on the west side. On the long sides, two plenums intake air from the outside to create a natural convection cooling circuit, removing the heat generated by the machines and exhausting it as hot air to a vent located on the ridge of the roof of the 14.50 m high linear section. The design process of the building had to take a flexible, step-by-step approach, and be led by the gradual development and sizing of the machine, which had never been built before. Several types of building envelopes were assessed, including metal, prefab concrete, and one made entirely of wood. The machinery, located mainly inside the building, is complemented by additional stacks, cyclones, and connection lines located outside the building envelope, mainly on its south side so as not to interfere with rail and lorry transport activities for the wood, which take place in the yard adjacent to the north side of the building. The building envelope interfaces therefore with the internal and external plant, while supporting a range of processing equipment which remains visible and connects the Plaxil 8 plant to the facilities nearby, establishing a network more than a stand-alone building. While defining the envelope, we looked at first into partitioning the 300 m linear extension into a number of modular house-like divisions, surmounted by a metal cornice located on the top of the mat formation plant, and featuring a large diagonal slope connecting the higher section to the lower section. Using that approach, the visual order of the building could have served as a counterbalance to the apparent random placement of machinery and lines. The final decision, however, was that of not contrasting individual building shapes against the machinery, but rather to ensure that the building would act as a backdrop and as a screen to the machinery, creating several levels of depth in the campus landscape. In this process of clarification of the role of architecture in relation to machines, the concept of INTERFACE has developed: the building is no longer a container that encloses the production process and represents it with an autonomous envelope, but is instead a visual scaffolding that dialogues with the machinery, involving them in the creation of a new landscape that includes interior and exterior, structure and production structures, new envelope and existing plants. The entire lower section of the building is clad using prefab concrete panels cast onto corrugated sheet metal forms, to create a continuous fretted texture setting out the metal vectors entering and exiting the building. The sloped section of the roof is also covered by reflective metal panels, ribbed vertically to retain the large diagonal “fillet” that characterises the silhouette of the building against the sky. The stacks and the cyclones of the mat formation plant are enclosed instead and partially hidden by an expanded metal mesh structure. These three types of cladding counterbalance the sight of the naked machines, while never conflicting with them. The existing structures enter into a dialogue with the new stacks and lines, and create a congruent skyline within the campus, a backdrop with multiple elements and scenes. This counterpoint is implemented by the network of connections that the transport lines of the finished panels coming from Plaxil 8 create with the existing buildings. In particular, the Rack Sigmat, with its lining in ribbed metal panels, is a new airy building composed of linear sections and centralized blocks that fly over the existing warehouses and join the “cathedral” of Plaxil 5. The interior also interacts with the machinery, left exposed, creating a new visual scaffolding for the production process. It has been possible to leave the structure in metal carpentry visible thanks to a special exemption of the Fire Department, justified by the fact that stacks of MDF panels, packaged for the final transport, do not let fire propagate and extinguish in less than a minute. This has made it possible to build a crescendo of lightweight overlapping frames with beams and pillars in double-T profiles that position the machines on different levels, obtaining a new internal transparency. The frame of the various levels of the mat formation plant more than fifty metres high, creates a spectacular vertical stratification while the sequence of reticular portals that enclose the press and the unloading line create an infinite linear perspective. Here too, it is not only the visible structure that defines the character of the interior, but its relationship with the machines placed at various levels: the heavy is supported by a light transparent scaffolding that puts the machinery on stage, placing them as if on a stage formed by various levels of depth. Again, the concept of “interface” informs the spaces of Plaxil 8 and the relationship between architecture and machine. Doing so, Plaxil 8 more than exceeds the previous idea of multiple discrete envelopes, and suggests an architectural discourse made of a succession of surfaces, extending past multiple buildings and glimpsed through the textures of the covers and the visual transparency of the screens. This “interface” strategy extends to the experience of Studio Valle in experimenting with industrial buildings and creating interplays with the continuously evolving industrial landscape of the location was instrumental to the success of the project.

Project design team
Pietro Valle with Roland Henning, Marco Carnelutti, Luisa Foretich, Stefano Bindi

Structural design and construction supervision
Mg Progetti (Mario Gallinaro with Enrico Toninato, Davide Pastore, Silvia Turato)

Production plants design
Dieffenbacher