P&ID Layout Styles

Grouped Equipment Layout
This layout style emphasizes processing interrelationships between closely associated, often interactive equipment. It is used for plants where several feed/product streams are processed concurrently, such as on-plot process facilities (the major manufacturing areas of plants, as opposed to off-plot, or support, areas), utility generation facilities, water and waste treating facilities, etc. (see Figure 200-3). To keep drawing lengths manageable, the facility is divided into essentially independent functioning elements. For a large processing plant these elements might include furnaces, reactors, distillation columns (towers), compressors, etc., that can be conveniently grouped on separate drawings. On the separate drawings, lines handling lighter products are drawn along the top, lines handling the heavier products along the bottom.

Serial Equipment Layout
This is a convenient layout for plants with a single major process stream that is acted upon sequentially at essentially independent stations, for instance, a packaging plant or production facility (see Figure 200-4). The P&IDs for plants laid out in this style can be many feet long when on a roll or multifold paper. When properly laid out, these may be broken down into individual drawings to more easily fit desktops or for inclusion in record books. Each segment holds usually one, sometimes two processing elements.

Serial-style P&IDs often have equipment information blocks along the top, process gas, relief, vent and flare headers just below, the equipment in the middle, interconnection lines just below the equipment, and pumps and compressors along the lower edge.

Geographical Layout
This layout is used for collections of independent processing elements that are not linked by process relationships, such as tankfields, utility distribution systems, plot limit manifolds, and interconnection diagrams. A roughly geographical layout is often the most logical way to present them. (See Figure 200-5).