by The process unit plot plan is an arrangement drawing that consists the equipments ,pipe racks and buildings.These are required for a given process integrated within a common battery limit area ,usually designed for independent operation and shutdown.The final plot plan contains all the components by designated numbers and shows to scale ,the basic shape of the equipments and supporting facilities ,locating them in both the vertical and the horizontal planes.Plot plans developed with three dimensional models have the advantage of producing multiple plans,elevations and isometric views.
The plot plan is used for various purposes by departments as per below mentioned,
Piping design – Plot plan is used to produce equipment arrangement studies for the interconnection of above-ground and below-ground process and utility piping systems and to estimate piping material quantities
Civil engineering – Plot plan is used to develop grading and drainage plans, holding ponds, diked areas, foundations and structural designs and all bulk material estimates.
Electrical engineering – Plot plan is used to locate switchgear and the incoming substation and motor control center ,to route cables and to estimate bulk materials.
Instrument engineering – Plot plan is used to lacate analyzer houses and cable trays ,the main control house and to estimate bulk materials.
Process engineering – Plot plan is used for hydraulic design ,line sizing and utility block flow requirements.
Scheduling – Plot plan is used to schedule the orderly completion of engineering design.
Construction – Plot plan is used to schedule the erection sequence of all equipments which includes large lifting studies,constructibilty reviews,and laydown areas throughout the entire construction phase.
Estimating – plot plan is used to estimate the overall cost of the plant.
Client use – Plot plan is used for safety ,operator and maintenance reviews and to develop as-built record of the plant arrangement.
PLOT PLAN DEVELOPMENT:
For developing the plot plan the designer must assemble the below mentioned information.
Equipment list – This list contains all the items of equipments and buildings by number and description to be included within the process battery limits.
Process flow diagram – Process flow diagram is required by the designer and the most important document to position the equipments.It indicates the flow rates,temperatures and pressures and how the various equipments are interconnected.
Block flow diagram – Block flow diagram shows all primary interconnecting lines between process units,utility plants and storage facilities.
Specifications – Plant layout specifications indicates the maintenance ,operator access,clearances and equipment spacing.
Process design data – Process design data indicates the location and extent of real estate available for the new facility or expansion and indicates the site weather conditions, temperatures ,rainfall records and pervailing winds and it also provides the plant elevation datum and reference coordinates for plant location.
Equipment sizes as the phase of the projects will be provided by supporting departments to update the same in the plot plan which it has been developed with preliminary information only.
BASIC INFORMATION FOR DEVELOPING A PLOT PLAN
Process units and capacities
Process Flow diagram (PFD)
Utility requirements
Storage facilities if any
Product despatch and transportation
Operating and maintenance philosophy
Technical and non -technical buildings
Site location map
Prevailing wind direction
Area topography contour map
Electrical supply source and direction of entry
Plant raw material entry
Operating and maintenance philosophy
Approach to main plant entry
Before starting the detailed engineering activity with the plot plan the above considerations shall be followed.
