In any industrial process, and in our particular as manufacturers and installers of pressure equipment (thermal fluid heaters, vaporizers, steam boilers, heat exchangers, electric boilers …) often, we find sizeable facilities and with multitude of elements, materials and instruments that the facility includes.
To identify these equipment and instruments in a simple way and also to get an idea of the design conditions of any engineering project, we use a tool that is commonly known by the acronym P&ID.
P&ID is defined as a diagram of piping and instrumentation and it shows the process flow in pipes, as well as, the equipment installed and instrumentation.
Another possible name used for a P&ID is PFD which is a simplified form (Process flow diagram), although this is a less used.
These diagrams are composed of a series of symbols that allow us to identify all the components that make up a process, such as pipes, number of piping lines and their dimensions, valves, controls, alarms, equipment, levels, pressure switches, drains, purges, pumps etc..
The instrument standard symbols used in these diagrams are generally based on ISA S5.1. standard, society Automation and Instrumentation Systems.
This standard of symbols are used in both chemical and petrochemical industry, metallurgical, air conditioning industry, power generator industries and many other numerous industrial processes.
In addition to these symbols, different types of lines and circles are used to indicate how interconnected are the various elements of the process and functions of each instrument.