Instrumentation Drawings & Symbols

This Instrumentation Drawings and symbols course document was intended to help the reader comprehend the numerous codes and symbols used to depict instrumentation in facilities designed to produce oil, gas, and related hydrocarbon products. Technical diagrams such as Process Flow Schemes (PFD) and Pipeline and Instrumentation Drawings graphically represent instrument codes and symbols (P&ID).

Such drawings are very useful for operation and maintenance specialists who must comprehend the process control systems linked with an installation. However, challenges are frequently encountered, owing to the availability of multiple systems of instrument codes and symbols developed through time by owners and contractors that carry out the engineering design, construction, and operation of processing installations.

The Function of Codes and Symbols

The major goal of employing codes and symbols is to clearly and concisely express the numerous instrument functions required in a process on Process Flow Diagrams (PFD) and Pipeline and Instrumentation Drawings (P&ID). The function codes and symbols of the measuring instrument and control device indicate which process parameter is being measured, the relative locations of the measurement and control devices, and the allowed limits applicable to particular variable process conditions.

Special symbols are used to signify the computer and the instruments that are connected to it in circumstances when supervisory computer systems are placed in a system. Letter codes and symbols, for example, allow the following instrument's functions to be graphically represented.

Instrument Codes for Process Monitoring

Flow rate (F)

Flow level (L)

Pressure (P)

Quality (Q)

Speed (S)

Temperature (T)

These codes are used with various symbols to differentiate between indicators, recorders, and, in some situations, their geographic locations. There are numerous sheets at the conclusion of this section that offer a wide range of suitable instrument symbols and acronyms.

Objectives of the Instrumentation Drawings and Symbols Course.

At the completion of this module, the trainee will have an understanding of:

1. Instrumentation symbols and abbreviations,

2. Structure of instrument codes (Tag Numbers),

3. Process Block Diagram

4. Process Flow Diagram (PFD)

5. Piping and Instrumentation Drawing (P&ID)

6. Electrical Loop Drawing

7. DCS (I/O) Input & Output Loop Drawing

8. Pneumatic Loop drawing

9. Cause and Effect Diagram

10. Functional Logic Diagram

11. Instrument Installation Hook-Up Diagram (Pneumatic or Process)

Measurement of Pressure

The force exerted per unit area of the surface is described as pressure. Oil and gas production processes necessitate the regulation of system operating pressures to certain pressures in order for the system(s) to function properly.

Furthermore, for safety reasons, system operating pressures must be monitored and managed to ensure that the pressure limits of the equipment and piping are not exceeded. To achieve these goals, the industry relies on a range of devices to produce an output signal that can be utilized to regulate or vary the measured pressure. This document describes the equipment used in the oil and gas sector for sensing operating pressures and generating the required output signals.