rel="nofollow" href="#ulink_d06b302a-d6f3-53dc-82e6-6f70f547e5ad">2.7 Panel and Field Instrument Specifications
2.10 Equipment Location Drawings
2.11 Control System Architecture Diagram
3.0 PROCESS AND INSTRUMENTATION DIAGRAMS AS COMMUNICATION TOOLS
3.1 Contract Bid Documents
3.2 End User and Owner Feedback
3.4 Operator-Interface Graphics Development
3.6 Coordination with Other Design Disciplines
4.0 INTELLIGENT PROCESS AND INSTRUMENTATION DIAGRAMS
4.1 Streamlined Diagram Development
4.1.3 Integration with External Data Sources
4.1.6 Review and Navigation Tools
4.1.7 Component Management Tools
4.2 Automatically Generated Lists
4.3 Design History for As-Built Drawings
4.4 Construction, Startup, Operation, Maintenance, and Asset Management Uses
5.0 PROCESS AND INSTRUMENTATION DIAGRAMS FOR NONPROCESS SYSTEMS
1.0 INTRODUCTION
Instrumentation and controls (I&C) systems represent an integral part of designing a new or upgraded water resource recover facility (WRRF). As such, process and instrumentation diagrams (P&IDs) are an important part of the process.
Process and instrumentation diagrams are schematics that illustrate all the components of a WRRF. A P&ID typically provides enough information for the project team and stakeholders to understand how the treatment process will be measured and controlled, but leaves out details that require a specialist’s expertise. These details are covered in related specifications, data sheets, instrument lists, logic diagrams, and installation details.
Design engineers have various philosophies on how to use P&IDs in WRRF design. Some engineers, for example, use them to develop piping and equipment designs. However, this approach can make other design documents too dependent on P&IDs and can actually hinder their progress.
A more common approach is to use P&IDs to develop instrumentation and electrical designs. In this instance, P&IDs would include all instrumentation connections, control panels, workstations, signal lines, and electrical power needs. For example, it would show which instruments and control panels need 120 VAC and which control valves and other elements need air supply. It also might include other equipment’s power needs, motor control centers (MCCs), variable-frequency drives (VFDs), and power distribution. Electrical engineers would then use P&IDs to develop power-distribution drawings for all equipment.
Mechanical engineers use P&IDs to develop piping designs. (The precursor to P&ID development is a process flow diagram [PFD], which is described later in this chapter.) As such, they need the diagrams to show all wall-mounted, panel-mounted, and freestanding instruments, in addition to in-line devices (e.g., magnetic flow meters and pressure taps) mounted on the process equipment (e.g., tanks, centrifuges, and scrubbers). Analytical instruments such as water quality analyzers, gas detection analyzers, and so on are also included in P&IDs. Sometimes, P&IDs also include instruments that are part of a vendor-supplied skid-mounted package. These details are necessary to ensure that piping, including required straight runs before and after a meter, is configured properly. For more information on all the documents included in a complete automation design, see Chapter 3.
2.0 HOW TO CREATE A PROCESS AND INSTRUMENTATION DIAGRAM
When creating a P&ID, design engineers should follow these steps (see Figure 4.1 for an example of a typical P&ID):
1. Start with a PFD and expand into multiple sheets by breaking up the PFD into appropriate logical segments, if needed, to fully show all process, instrument, panel, and equipment details needed for a P&ID;
2. Create a legend sheet specific to the project, defining all symbols, abbreviations, numbering scheme, and other conventions to be used;
3. Develop an instrumentation numbering system based on the International Society of Automation (ISA) Standard ISA-5.1,
