【正文】 o the assembling of the Polypropylene Spheres on site, one job which needs highly specialized constructors on the specific activity and its value didn’t ever exceed the GDR.Although the preliminary studies made by the Owner related to the viability of its investment in the international environment were satisfied with the plant’s ability for production of tones polypropylene per year, later more mature and detailed studies were highlighting the need for higher production, in order the product to be cheaper and more petitive both to national and international markets.The main stages of the projectThe Project consists of the following main disciplines of works:Civil WorksUnder this discipline are included all earthworks, foundations, steel structures, industrial paving, erection of buildings, underground piping works and pits.Mechanical WorksUnder this discipline are included all piping works (prefabrication, erection, non destructive inspections and hydraulic or pneumatic tests), equipment erection (such as the reactor, the extruder, silos, vessels, flare, tanks, drums, pressors, valves, pumps etc.), fire fighting system, pneumatic haulage system and bagging system and the fabrication and erection of steel supports.Electrical WorksUnder this discipline are included all installations of power transformers, switchgears, telemunication systems, the motor connections, the laying of cables and the erection of all the cable trays, the earthing system, the lighting system, the electric heating system etc…Instrument WorksUnder this discipline are included all installations of instruments, their connections and terminations, the laying of the instrument cables, the wiring in the control room, the installation of cabinets, consoles and the installation of all the control room etc…Insulation WorksUnder this discipline is included the cold and hot insulation of all the piping elements, equipment and instruments of the project, wherever such an instruction is given by the specifications and the drawings.Painting WorksUnder this discipline is included the sandblasting and painting of all the steel supports, the sandblasting of many piping spools before their erection, the painting of erected piping and equipment, wherever this is instructed through the relevant specifications and the painting of all the steel structures of the Project.Pipeline (Underground laying and offshore utilities)Under this discipline was included the inspection of the existing pipeline system from the limits of the refinery up to its sea platform (which is established 800mt from the coast), the tracing of a new pipeline, the detailed design, all the required procurement of materials and equipment and final all the construction phase. The construction phase includes the fabrication and erection of one loading arm[1] in a sea platform terminal – 800mt from the coast – and the interconnection with the project through a plex of valves and of one 10 inches pipeline of almost m length, from which the 800mt are laid underwater and the rest are laid underground. For this part of the works only in the whole Project, Contractor in its scope of work had also the design, the procurement of all piping and equipment and the premissioning and missioning activities.In general, all works of the disciplines are separated in the following stages:The design, the procurement and delivery on the site of the materials and the equipment, the construction period, and the premissioning and missioning period. Contractor as the Main Subcontractor of the Project had in its scope of the work, only the erection activities and the procurement of all building materials, such as bricks, cement, rebars, road bitumen, a part of the steel structures, all the steel supports and cable trays and the materials for insulation and painting.All the equipment, piping, cables, instruments, the major part of the steel structures were procured and delivered on site by the Engineering pany.The project for planning and progress monitoring only was divided by Engineer into the following 13 main functional units as shown below: Polymerization Other Building (Office Building Catalyst Storage) Warehouse / Silos / Bagging Area Concrete Foundations for the Steel Structures and construction of other buildings, like Electrical Substation, Control Room, Administration Buildings, Warehouses etc. Cable Trays erection. Laying of electrical cables. Hydraulic and Pneumatic tests of piping and final reinstatement of all pipe lines and of all the instruments connected on them.Critical ActivitiesNot all of the above activities are critical for the start of the posterior activities. But for instance the erection of the main steel structures is essential for the start of the rest of the activities. All the pipes (small and large bore) are connected with some kind of equipment, like a vessel, a pressor, a pump