Consideration of plot plan layout in this chapter is related to an Oil Refinery or Chemical Plant. However, the majority of Process Plants require a plot plan with somewhat less stringent and less complicated arrangements. Equipment spacing requirements will vary with the type of plant and location.
Plot plans are considered key documents to projects and are normally initiated in the pre-contract, conceptual and development stages of a proposal. After the contract is awarded for engineering, plot plans are developed at a rather rapid pace with very limited information. This early stage plot plan usually is very limited in detail, containing only enough dimensional data to define the outer limits of the available property selected for plant development. Located within the boundaries of the available property, rough equipment sizes and shapes are pictorially positioned, along with anticipated pipe rack configurations, structure shape and rough sizes.
Once approved by the client, almost every group including Engineering, Scheduling, Construction, Operations, Cost Control, Estimating and Material Control use the plot plan as a pictorial reference for their work. At this point, the plot plan becomes a universal document used by all groups to interface with one another and the client.
Development of the plot plan in the very early stages is usually accomplished through the use of preliminary project design data, approximate equipment sizes and a process flow diagram to establish rough sketches. These sketches are used to determine structure configuration and relative equipment positioning.
The plot plan is then "proven" by using a process flow diagram, marked up to depict the more expensive piping, such as alloy or large diameter piping. This "high dollar" piping is usually marked in a point-to-point fashion in a specific color on a print of the plot plan. The balance of the process piping is then point-to-point connected in another color to prove the cost effectiveness of the selected equipment arrangement.
