【正文】 ntrol Room Area Other Building (Office Building Catalyst Storage) Spheres Area Interconnecting Pipe racks (ISBL Area) Interconnecting Pipe racks (OSBL Area) Warehouse / Silos / Bagging Area Underground AreaFor someone not familiar with the petrochemical and in general the industrial construction activities, it should be remarked here that the ordinary series of activities between the main categories of the activities are the following: Mobilization on site, Excavations Concrete Foundations for the Steel Structures and construction of other buildings, like Electrical Substation, Control Room, Administration Buildings, Warehouses etc. The steel structures which include interconnecting pipe racks or buildings on which they will be seated the equipment. Prefabrication of large bore Piping (pipes with more than 2 inches diameter). Erection of Equipment. Cable Trays erection. Fabrication and erection of pipe supports. Erection of large bore piping. Erection of small bore piping (pipes with equal or less than 2 inches diameter) and erection of additional supports. Laying of electrical cables. Laying of instrument cables. Installation of Junction Boxes, DCS, Cabinets, erection of instruments, wiring on control room etc. Connections and terminations of 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, the reactor, the extruder etc. Notwithstanding to what is expected, the installation of the equipment is not crucial for the fabrication or even the erection of the large bore pipes because the location of the large bore pipes on site is in accordance to the drawings and not with the final position of the equipment and it is not required in any specification the prior installation of the equipment, on the contrary the small bore pipes have to be located after the installation of the equipment, because their exact position and alignment with the equipment (especially with those having rotary parts, such as the pumps and the pressors) and it has always to be checked in the field prior to their erection.Furthermore, there are dozens of other similar prerequisites that an experienced project management and planning team should have taken into account during the issue of the planning schedule of the project and follow closely during the whole construction phase.It should be noticed here also the following: that each area of the plant was discrete from the others (with the exception of the interconnecting pipe racks, which they were covering parts of all the areas of the Project) and the activities that were taking place in one area were not critical for the start of the activities in another area until the mechanical pletion of the works.Coclusions: Problems that created delays and disruption to the progress of the works.Premature start of premissioning and missioning activities had detrimental consequences and caused extensive delay and disruption to Contractor’s works: Engineer was working concurrently in the same area with Contractor. Engineer was drawing on Contractor’s resources to assist Engineer in its premature activities. Engineer had forced Contractor’s attention to support Engineer in clearing minor defects related to premissioning and missioning activities instead of Contractor concentrating its efforts on achieving the overall Mechanical Completion, which was Contractor’s primary and preceding contractual obligation. The earlier mencement of Engineer’s premissioning and missioning activities unveiled numerous problems in Engineer’s engineering that led to instructions for changes, even to tested sections of Works. Engineer’s Commissioning Team as well as other subcontractors employed by Engineer for missioning purposes caused extensive damages to Contractor’s pleted works. In many instances these works had not yet been handedover to Engineer, increasing Contractor’s rework. Furthermore, extensive modifications were executed to Contractor’s pleted works by Engineer’s missioning team and other subcontractors, without notice to Contractor and without its consent. The lack of munication prevailing between Engineer’s construction and missioning departments resulted in conflicting instructions being issued to Contractor.figure 1figure 2figure 3Figure 4Fishbone AnalysisCause and Effect Diagram – Fishbone Analysis of theCOSTCause and Effect Diagram – Fishbone Analysis of the DELAYS